diff --git a/Cargo.lock b/Cargo.lock
index a4697493..14f0bbbf 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3875,6 +3875,20 @@ dependencies = [
  "yansi",
 ]
 
+[[package]]
+name = "prometheus"
+version = "0.13.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d33c28a30771f7f96db69893f78b857f7450d7e0237e9c8fc6427a81bae7ed1"
+dependencies = [
+ "cfg-if",
+ "fnv",
+ "lazy_static",
+ "memchr",
+ "parking_lot",
+ "thiserror 1.0.69",
+]
+
 [[package]]
 name = "psl-types"
 version = "2.0.11"
@@ -5824,12 +5838,14 @@ dependencies = [
  "mini-moka",
  "num-derive",
  "num-traits",
+ "once_cell",
  "opendal",
  "openidconnect",
  "openssl",
  "pastey 0.2.1",
  "percent-encoding",
  "pico-args",
+ "prometheus",
  "rand 0.9.2",
  "regex",
  "reqsign",
diff --git a/Cargo.toml b/Cargo.toml
index 9d54590e..62def08c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -37,6 +37,8 @@ vendored_openssl = ["openssl/vendored"]
 # Enable MiMalloc memory allocator to replace the default malloc
 # This can improve performance for Alpine builds
 enable_mimalloc = ["dep:mimalloc"]
+# Enable Prometheus metrics endpoint
+enable_metrics = ["dep:prometheus"]
 s3 = ["opendal/services-s3", "dep:aws-config", "dep:aws-credential-types", "dep:aws-smithy-runtime-api", "dep:anyhow", "dep:http", "dep:reqsign"]
 
 # OIDC specific features
@@ -77,6 +79,9 @@ rmpv = "1.3.1" # MessagePack library
 # Concurrent HashMap used for WebSocket messaging and favicons
 dashmap = "6.1.0"
 
+# Lazy static initialization
+once_cell = "1.20.2"
+
 # Async futures
 futures = "0.3.31"
 tokio = { version = "1.49.0", features = ["rt-multi-thread", "fs", "io-util", "parking_lot", "time", "signal", "net"] }
@@ -182,6 +187,9 @@ semver = "1.0.27"
 # Mainly used for the musl builds, since the default musl malloc is very slow
 mimalloc = { version = "0.1.48", features = ["secure"], default-features = false, optional = true }
 
+# Prometheus metrics
+prometheus = { version = "0.13.1", default-features = false, optional = true }
+
 which = "8.0.0"
 
 # Argon2 library with support for the PHC format
diff --git a/README.md b/README.md
index c84a9c40..3835968f 100644
--- a/README.md
+++ b/README.md
@@ -52,6 +52,7 @@ A nearly complete implementation of the Bitwarden Client API is provided, includ
      [Duo](https://bitwarden.com/help/setup-two-step-login-duo/)
  * [Emergency Access](https://bitwarden.com/help/emergency-access/)
  * [Vaultwarden Admin Backend](https://github.com/dani-garcia/vaultwarden/wiki/Enabling-admin-page)
+ * [Prometheus Metrics](https://github.com/dani-garcia/vaultwarden/wiki/Metrics) - Optional monitoring and observability with secure endpoint
  * [Modified Web Vault client](https://github.com/dani-garcia/bw_web_builds) (Bundled within our containers)
 
 <br>
diff --git a/docker/Dockerfile.alpine b/docker/Dockerfile.alpine
index 95aae642..0658a9e0 100644
--- a/docker/Dockerfile.alpine
+++ b/docker/Dockerfile.alpine
@@ -82,7 +82,7 @@ ARG CARGO_PROFILE=release
 
 # Configure the DB ARG as late as possible to not invalidate the cached layers above
 # Enable MiMalloc to improve performance on Alpine builds
-ARG DB=sqlite,mysql,postgresql,enable_mimalloc
+ARG DB=sqlite,mysql,postgresql,enable_mimalloc,enable_metrics
 
 # Builds your dependencies and removes the
 # dummy project, except the target folder
diff --git a/docker/Dockerfile.debian b/docker/Dockerfile.debian
index 113304b8..bbc952aa 100644
--- a/docker/Dockerfile.debian
+++ b/docker/Dockerfile.debian
@@ -116,7 +116,7 @@ COPY ./macros ./macros
 ARG CARGO_PROFILE=release
 
 # Configure the DB ARG as late as possible to not invalidate the cached layers above
-ARG DB=sqlite,mysql,postgresql
+ARG DB=sqlite,mysql,postgresql,enable_metrics
 
 # Builds your dependencies and removes the
 # dummy project, except the target folder
diff --git a/docker/Dockerfile.j2 b/docker/Dockerfile.j2
index f745780e..2f55843d 100644
--- a/docker/Dockerfile.j2
+++ b/docker/Dockerfile.j2
@@ -144,10 +144,10 @@ ARG CARGO_PROFILE=release
 
 # Configure the DB ARG as late as possible to not invalidate the cached layers above
 {% if base == "debian" %}
-ARG DB=sqlite,mysql,postgresql
+ARG DB=sqlite,mysql,postgresql,enable_metrics
 {% elif base == "alpine" %}
 # Enable MiMalloc to improve performance on Alpine builds
-ARG DB=sqlite,mysql,postgresql,enable_mimalloc
+ARG DB=sqlite,mysql,postgresql,enable_mimalloc,enable_metrics
 {% endif %}
 
 # Builds your dependencies and removes the
diff --git a/src/api/identity.rs b/src/api/identity.rs
index 9eaa6b36..cca87ea0 100644
--- a/src/api/identity.rs
+++ b/src/api/identity.rs
@@ -32,7 +32,7 @@ use crate::{
     error::MapResult,
     mail, sso,
     sso::{OIDCCode, OIDCCodeChallenge, OIDCCodeVerifier, OIDCState},
-    util, CONFIG,
+    util, CONFIG, metrics,
 };
 
 pub fn routes() -> Vec<Route> {
@@ -60,7 +60,8 @@ async fn login(
 
     let mut user_id: Option<UserId> = None;
 
-    let login_result = match data.grant_type.as_ref() {
+    let auth_method = data.grant_type.clone();
+    let login_result = match auth_method.as_ref() {
         "refresh_token" => {
             _check_is_some(&data.refresh_token, "refresh_token cannot be blank")?;
             _refresh_login(data, &conn, &client_header.ip).await
@@ -104,6 +105,10 @@ async fn login(
         t => err!("Invalid type", t),
     };
 
+    // Record authentication metrics
+    let auth_status = if login_result.is_ok() { "success" } else { "failed" };
+    metrics::increment_auth_attempts(&auth_method, auth_status);
+
     if let Some(user_id) = user_id {
         match &login_result {
             Ok(_) => {
diff --git a/src/api/metrics.rs b/src/api/metrics.rs
new file mode 100644
index 00000000..a244f053
--- /dev/null
+++ b/src/api/metrics.rs
@@ -0,0 +1,98 @@
+use rocket::{
+    request::{FromRequest, Outcome, Request},
+    response::content::RawText,
+    Route,
+};
+
+use crate::{auth::ClientIp, db::DbConn, CONFIG};
+
+pub fn routes() -> Vec<Route> {
+    if CONFIG.enable_metrics() {
+        routes![get_metrics]
+    } else {
+        Vec::new()
+    }
+}
+
+pub struct MetricsToken {
+    _ip: ClientIp,
+}
+
+#[rocket::async_trait]
+impl<'r> FromRequest<'r> for MetricsToken {
+    type Error = &'static str;
+
+    async fn from_request(request: &'r Request<'_>) -> Outcome<Self, Self::Error> {
+        let ip = match ClientIp::from_request(request).await {
+            Outcome::Success(ip) => ip,
+            _ => err_handler!("Error getting Client IP"),
+        };
+
+        let Some(configured_token) = CONFIG.metrics_token() else {
+            return Outcome::Success(Self { _ip: ip });
+        };
+
+        let provided_token = request
+            .headers()
+            .get_one("Authorization")
+            .and_then(|auth| auth.strip_prefix("Bearer "))
+            .or_else(|| request.query_value::<&str>("token").and_then(|result| result.ok()));
+
+        match provided_token {
+            Some(token) => {
+                if validate_metrics_token(token, &configured_token) {
+                    Outcome::Success(Self { _ip: ip })
+                } else {
+                    err_handler!("Invalid metrics token")
+                }
+            }
+            None => err_handler!("Metrics token required"),
+        }
+    }
+}
+
+fn validate_metrics_token(provided: &str, configured: &str) -> bool {
+    if configured.starts_with("$argon2") {
+        use argon2::password_hash::PasswordVerifier;
+        match argon2::password_hash::PasswordHash::new(configured) {
+            Ok(hash) => argon2::Argon2::default().verify_password(provided.trim().as_bytes(), &hash).is_ok(),
+            Err(e) => {
+                error!("Invalid Argon2 PHC in METRICS_TOKEN: {e}");
+                false
+            }
+        }
+    } else {
+        crate::crypto::ct_eq(configured.trim(), provided.trim())
+    }
+}
+
+/// Prometheus metrics endpoint
+#[get("/")]
+async fn get_metrics(_token: MetricsToken, mut conn: DbConn) -> Result<RawText<String>, crate::error::Error> {
+    if let Err(e) = crate::metrics::update_business_metrics(&mut conn).await {
+        err!("Failed to update business metrics", e.to_string());
+    }
+
+    match crate::metrics::gather_metrics() {
+        Ok(metrics) => Ok(RawText(metrics)),
+        Err(e) => err!("Failed to gather metrics", e.to_string()),
+    }
+}
+
+/// Health check endpoint that also updates some basic metrics
+#[cfg(feature = "enable_metrics")]
+pub async fn update_health_metrics(_conn: &mut DbConn) {
+    // Update basic system metrics
+    use std::time::SystemTime;
+    static START_TIME: std::sync::OnceLock<SystemTime> = std::sync::OnceLock::new();
+    let start_time = *START_TIME.get_or_init(SystemTime::now);
+
+    crate::metrics::update_uptime(start_time);
+
+    // Update database connection metrics
+    // Note: This is a simplified version - in production you'd want to get actual pool stats
+    crate::metrics::update_db_connections("main", 1, 0);
+}
+
+#[cfg(not(feature = "enable_metrics"))]
+pub async fn update_health_metrics(_conn: &mut DbConn) {}
diff --git a/src/api/middleware.rs b/src/api/middleware.rs
new file mode 100644
index 00000000..4e43c78b
--- /dev/null
+++ b/src/api/middleware.rs
@@ -0,0 +1,176 @@
+/// Metrics middleware for automatic HTTP request instrumentation
+use rocket::{
+    fairing::{Fairing, Info, Kind},
+    Data, Request, Response,
+};
+use std::time::Instant;
+
+pub struct MetricsFairing;
+
+#[rocket::async_trait]
+impl Fairing for MetricsFairing {
+    fn info(&self) -> Info {
+        Info {
+            name: "Metrics Collection",
+            kind: Kind::Request | Kind::Response,
+        }
+    }
+
+    async fn on_request(&self, req: &mut Request<'_>, _: &mut Data<'_>) {
+        req.local_cache(|| RequestTimer {
+            start_time: Instant::now(),
+        });
+    }
+
+    async fn on_response<'r>(&self, req: &'r Request<'_>, res: &mut Response<'r>) {
+        let timer = req.local_cache(|| RequestTimer {
+            start_time: Instant::now(),
+        });
+        let duration = timer.start_time.elapsed();
+        let method = req.method().as_str();
+        let path = normalize_path(req.uri().path().as_str());
+        let status = res.status().code;
+
+        // Record metrics
+        crate::metrics::increment_http_requests(method, &path, status);
+        crate::metrics::observe_http_request_duration(method, &path, duration.as_secs_f64());
+    }
+}
+
+struct RequestTimer {
+    start_time: Instant,
+}
+
+/// Normalize paths to avoid high cardinality metrics
+/// Convert dynamic segments to static labels
+fn normalize_path(path: &str) -> String {
+    let segments: Vec<&str> = path.split('/').collect();
+    let mut normalized = Vec::new();
+
+    for segment in segments {
+        if segment.is_empty() {
+            continue;
+        }
+
+        let normalized_segment = if is_uuid(segment) {
+            "{id}"
+        } else if is_hex_hash(segment) {
+            "{hash}"
+        } else if segment.chars().all(|c| c.is_ascii_digit()) {
+            "{number}"
+        } else {
+            segment
+        };
+
+        normalized.push(normalized_segment);
+    }
+
+    if normalized.is_empty() {
+        "/".to_string()
+    } else {
+        format!("/{}", normalized.join("/"))
+    }
+}
+
+/// Check if a string is a hex hash (32+ hex chars, typical for SHA256, MD5, etc)
+fn is_hex_hash(s: &str) -> bool {
+    s.len() >= 32 && s.chars().all(|c| c.is_ascii_hexdigit())
+}
+
+/// Check if a string looks like a UUID
+fn is_uuid(s: &str) -> bool {
+    s.len() == 36
+        && s.chars().enumerate().all(|(i, c)| match i {
+            8 | 13 | 18 | 23 => c == '-',
+            _ => c.is_ascii_hexdigit(),
+        })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_normalize_path_preserves_static_routes() {
+        assert_eq!(normalize_path("/api/accounts"), "/api/accounts");
+        assert_eq!(normalize_path("/api/sync"), "/api/sync");
+        assert_eq!(normalize_path("/icons"), "/icons");
+    }
+
+    #[test]
+    fn test_normalize_path_replaces_uuid() {
+        let uuid = "12345678-1234-5678-9012-123456789012";
+        assert_eq!(
+            normalize_path(&format!("/api/accounts/{uuid}")),
+            "/api/accounts/{id}"
+        );
+        assert_eq!(
+            normalize_path(&format!("/ciphers/{uuid}")),
+            "/ciphers/{id}"
+        );
+    }
+
+    #[test]
+    fn test_normalize_path_replaces_sha256_hash() {
+        // SHA256 hashes are 64 hex characters
+        let sha256 = "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef";
+        assert_eq!(
+            normalize_path(&format!("/attachments/{sha256}")),
+            "/attachments/{hash}"
+        );
+    }
+
+    #[test]
+    fn test_normalize_path_does_not_replace_short_hex() {
+        // Only consider 32+ char hex strings as hashes
+        assert_eq!(normalize_path("/api/hex123"), "/api/hex123");
+        assert_eq!(normalize_path("/test/abc"), "/test/abc");
+        assert_eq!(normalize_path("/api/abcdef1234567890"), "/api/abcdef1234567890"); // 16 chars
+        assert_eq!(normalize_path("/files/0123456789abcdef"), "/files/0123456789abcdef"); // 16 chars
+    }
+
+    #[test]
+    fn test_normalize_path_replaces_numbers() {
+        assert_eq!(normalize_path("/api/organizations/123"), "/api/organizations/{number}");
+        assert_eq!(normalize_path("/users/456/profile"), "/users/{number}/profile");
+    }
+
+    #[test]
+    fn test_normalize_path_root() {
+        assert_eq!(normalize_path("/"), "/");
+    }
+
+    #[test]
+    fn test_normalize_path_empty_segments() {
+        assert_eq!(normalize_path("//api//accounts"), "/api/accounts");
+    }
+
+    #[test]
+    fn test_is_uuid_valid() {
+        assert!(is_uuid("12345678-1234-5678-9012-123456789012"));
+        assert!(is_uuid("00000000-0000-0000-0000-000000000000"));
+        assert!(is_uuid("ffffffff-ffff-ffff-ffff-ffffffffffff"));
+    }
+
+    #[test]
+    fn test_is_uuid_invalid_format() {
+        assert!(!is_uuid("not-a-uuid"));
+        assert!(!is_uuid("12345678123456781234567812345678"));
+        assert!(!is_uuid("123"));
+        assert!(!is_uuid(""));
+        assert!(!is_uuid("12345678-1234-5678-9012-12345678901")); // Too short
+        assert!(!is_uuid("12345678-1234-5678-9012-1234567890123")); // Too long
+    }
+
+    #[test]
+    fn test_is_uuid_invalid_characters() {
+        assert!(!is_uuid("12345678-1234-5678-9012-12345678901z"));
+        assert!(!is_uuid("g2345678-1234-5678-9012-123456789012"));
+    }
+
+    #[test]
+    fn test_is_uuid_invalid_dash_positions() {
+        assert!(!is_uuid("12345678-1234-56789012-123456789012"));
+        assert!(!is_uuid("12345678-1234-5678-90121-23456789012"));
+    }
+}
diff --git a/src/api/mod.rs b/src/api/mod.rs
index ecdf9408..5d40c064 100644
--- a/src/api/mod.rs
+++ b/src/api/mod.rs
@@ -2,6 +2,8 @@ mod admin;
 pub mod core;
 mod icons;
 mod identity;
+mod metrics;
+mod middleware;
 mod notifications;
 mod push;
 mod web;
@@ -22,6 +24,8 @@ pub use crate::api::{
     core::{event_cleanup_job, events_routes as core_events_routes},
     icons::routes as icons_routes,
     identity::routes as identity_routes,
+    metrics::routes as metrics_routes,
+    middleware::MetricsFairing,
     notifications::routes as notifications_routes,
     notifications::{AnonymousNotify, Notify, UpdateType, WS_ANONYMOUS_SUBSCRIPTIONS, WS_USERS},
     push::{
diff --git a/src/api/web.rs b/src/api/web.rs
index d1ca0db4..3c33a779 100644
--- a/src/api/web.rs
+++ b/src/api/web.rs
@@ -179,7 +179,9 @@ async fn attachments(cipher_id: CipherId, file_id: AttachmentId, token: String)
 // We use DbConn here to let the alive healthcheck also verify the database connection.
 use crate::db::DbConn;
 #[get("/alive")]
-fn alive(_conn: DbConn) -> Json<String> {
+async fn alive(mut conn: DbConn) -> Json<String> {
+    // Update basic health metrics if metrics are enabled
+    let _ = crate::api::metrics::update_health_metrics(&mut conn).await;
     now()
 }
 
diff --git a/src/config.rs b/src/config.rs
index 4fb103fa..7d0d89f2 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -918,6 +918,16 @@ make_config! {
         /// Auto-enable 2FA (Know the risks!) |> Automatically setup email 2FA as fallback provider when needed
         email_2fa_auto_fallback: bool,  true,   def,      false;
     },
+
+    /// Metrics Settings
+    metrics {
+        /// Enable metrics endpoint |> Enable Prometheus metrics endpoint at /metrics
+        enable_metrics:         bool,   true,   def,    false;
+        /// Metrics token |> Optional token to secure the /metrics endpoint. If not set, endpoint is public when enabled.
+        metrics_token:          Pass,   true,   option;
+        /// Business metrics cache timeout |> Number of seconds to cache business metrics before refreshing from database
+        metrics_business_cache_seconds: u64, true, def, 300;
+    },
 }
 
 fn validate_config(cfg: &ConfigItems) -> Result<(), Error> {
@@ -1266,6 +1276,30 @@ fn validate_config(cfg: &ConfigItems) -> Result<(), Error> {
         println!("[WARNING] Secure Note size limit is increased to 100_000!");
         println!("[WARNING] This could cause issues with clients. Also exports will not work on Bitwarden servers!.");
     }
+
+    // Validate metrics configuration
+    if cfg.enable_metrics {
+        if let Some(ref token) = cfg.metrics_token {
+            if token.starts_with("$argon2") {
+                if let Err(e) = argon2::password_hash::PasswordHash::new(token) {
+                    err!(format!("The configured Argon2 PHC in `METRICS_TOKEN` is invalid: '{e}'"))
+                }
+            } else if token.trim().is_empty() {
+                err!("`METRICS_TOKEN` cannot be empty when metrics are enabled");
+            } else {
+                println!(
+                    "[NOTICE] You are using a plain text `METRICS_TOKEN` which is less secure.\n\
+                    Please consider generating a secure Argon2 PHC string by using `vaultwarden hash`.\n"
+                );
+            }
+        } else {
+            println!(
+                "[WARNING] Metrics endpoint is enabled without authentication. This may expose sensitive information."
+            );
+            println!("[WARNING] Consider setting `METRICS_TOKEN` to secure the endpoint.");
+        }
+    }
+
     Ok(())
 }
 
diff --git a/src/db/models/cipher.rs b/src/db/models/cipher.rs
index b28a25cd..497e8d8b 100644
--- a/src/db/models/cipher.rs
+++ b/src/db/models/cipher.rs
@@ -135,6 +135,24 @@ use crate::db::DbConn;
 use crate::api::EmptyResult;
 use crate::error::MapResult;
 
+#[derive(QueryableByName)]
+struct CipherCount {
+    #[diesel(sql_type = diesel::sql_types::Integer)]
+    atype: i32,
+    #[diesel(sql_type = diesel::sql_types::BigInt)]
+    count: i64,
+}
+
+#[derive(QueryableByName)]
+struct CipherOrgCount {
+    #[diesel(sql_type = diesel::sql_types::Integer)]
+    atype: i32,
+    #[diesel(sql_type = diesel::sql_types::Text)]
+    organization_uuid: String,
+    #[diesel(sql_type = diesel::sql_types::BigInt)]
+    count: i64,
+}
+
 /// Database methods
 impl Cipher {
     pub async fn to_json(
@@ -967,6 +985,56 @@ impl Cipher {
         }}
     }
 
+    pub async fn count_by_type_and_org(conn: &DbConn) -> std::collections::HashMap<(String, String), i64> {
+        use std::collections::HashMap;
+        db_run! { conn: {
+            // Count personal ciphers (organization_uuid IS NULL)
+            let personal_results: Vec<CipherCount> = diesel::sql_query(
+                "SELECT atype, COUNT(*) as count FROM ciphers WHERE deleted_at IS NULL AND organization_uuid IS NULL GROUP BY atype"
+            )
+            .load(conn)
+            .expect("Error counting personal ciphers");
+
+            // Count organization ciphers (organization_uuid IS NOT NULL)
+            let org_results: Vec<CipherOrgCount> = diesel::sql_query(
+                "SELECT atype, organization_uuid, COUNT(*) as count FROM ciphers WHERE deleted_at IS NULL AND organization_uuid IS NOT NULL GROUP BY atype, organization_uuid"
+            )
+            .load(conn)
+            .expect("Error counting organization ciphers");
+
+            let mut counts = HashMap::new();
+            for result in personal_results {
+                let cipher_type = match result.atype {
+                    1 => "login",
+                    2 => "note",
+                    3 => "card",
+                    4 => "identity",
+                    _ => "unknown",
+                };
+                counts.insert((cipher_type.to_string(), "personal".to_string()), result.count);
+            }
+            for result in org_results {
+                let cipher_type = match result.atype {
+                    1 => "login",
+                    2 => "note",
+                    3 => "card",
+                    4 => "identity",
+                    _ => "unknown",
+                };
+                counts.insert((cipher_type.to_string(), result.organization_uuid), result.count);
+            }
+            counts
+        }}
+    }
+
+    pub async fn find_all(conn: &DbConn) -> Vec<Self> {
+        db_run! { conn: {
+            ciphers::table
+                .load::<Self>(conn)
+                .expect("Error loading ciphers")
+        }}
+    }
+
     pub async fn get_collections(&self, user_uuid: UserId, conn: &DbConn) -> Vec<CollectionId> {
         if CONFIG.org_groups_enabled() {
             db_run! { conn: {
diff --git a/src/db/models/organization.rs b/src/db/models/organization.rs
index 0b722ef6..035402a7 100644
--- a/src/db/models/organization.rs
+++ b/src/db/models/organization.rs
@@ -403,6 +403,16 @@ impl Organization {
         }}
     }
 
+    pub async fn count(conn: &DbConn) -> i64 {
+        db_run! { conn: {
+            organizations::table
+                .count()
+                .first::<i64>(conn)
+                .ok()
+                .unwrap_or(0)
+        }}
+    }
+
     pub async fn get_all(conn: &DbConn) -> Vec<Self> {
         db_run! { conn: {
             organizations::table
diff --git a/src/db/models/user.rs b/src/db/models/user.rs
index e88c7296..bcafd548 100644
--- a/src/db/models/user.rs
+++ b/src/db/models/user.rs
@@ -409,6 +409,28 @@ impl User {
         None
     }
 
+    pub async fn count_enabled(conn: &DbConn) -> i64 {
+        db_run! { conn: {
+            users::table
+                .filter(users::enabled.eq(true))
+                .count()
+                .first::<i64>(conn)
+                .ok()
+                .unwrap_or(0)
+        }}
+    }
+
+    pub async fn count_disabled(conn: &DbConn) -> i64 {
+        db_run! { conn: {
+            users::table
+                .filter(users::enabled.eq(false))
+                .count()
+                .first::<i64>(conn)
+                .ok()
+                .unwrap_or(0)
+        }}
+    }
+
     pub async fn get_all(conn: &DbConn) -> Vec<(Self, Option<SsoUser>)> {
         db_run! { conn: {
             users::table
diff --git a/src/main.rs b/src/main.rs
index 8eef2e8c..d74ae5cc 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -54,6 +54,7 @@ mod crypto;
 mod db;
 mod http_client;
 mod mail;
+mod metrics;
 mod ratelimit;
 mod sso;
 mod sso_client;
@@ -89,6 +90,17 @@ async fn main() -> Result<(), Error> {
     db::models::TwoFactor::migrate_u2f_to_webauthn(&pool.get().await.unwrap()).await.unwrap();
     db::models::TwoFactor::migrate_credential_to_passkey(&pool.get().await.unwrap()).await.unwrap();
 
+    // Initialize metrics if enabled
+    if CONFIG.enable_metrics() {
+        metrics::init_build_info();
+        info!("Metrics endpoint enabled at /metrics");
+        if CONFIG.metrics_token().is_some() {
+            info!("Metrics endpoint secured with token");
+        } else {
+            warn!("Metrics endpoint is publicly accessible");
+        }
+    }
+
     let extra_debug = matches!(level, log::LevelFilter::Trace | log::LevelFilter::Debug);
     launch_rocket(pool, extra_debug).await // Blocks until program termination.
 }
@@ -567,14 +579,21 @@ async fn launch_rocket(pool: db::DbPool, extra_debug: bool) -> Result<(), Error>
 
     // If adding more paths here, consider also adding them to
     // crate::utils::LOGGED_ROUTES to make sure they appear in the log
-    let instance = rocket::custom(config)
+    let mut instance = rocket::custom(config)
         .mount([basepath, "/"].concat(), api::web_routes())
         .mount([basepath, "/api"].concat(), api::core_routes())
         .mount([basepath, "/admin"].concat(), api::admin_routes())
         .mount([basepath, "/events"].concat(), api::core_events_routes())
         .mount([basepath, "/identity"].concat(), api::identity_routes())
         .mount([basepath, "/icons"].concat(), api::icons_routes())
-        .mount([basepath, "/notifications"].concat(), api::notifications_routes())
+        .mount([basepath, "/notifications"].concat(), api::notifications_routes());
+
+    // Conditionally mount metrics routes if enabled
+    if CONFIG.enable_metrics() {
+        instance = instance.mount([basepath, "/metrics"].concat(), api::metrics_routes());
+    }
+
+    let mut rocket_instance = instance
         .register([basepath, "/"].concat(), api::web_catchers())
         .register([basepath, "/api"].concat(), api::core_catchers())
         .register([basepath, "/admin"].concat(), api::admin_catchers())
@@ -583,9 +602,14 @@ async fn launch_rocket(pool: db::DbPool, extra_debug: bool) -> Result<(), Error>
         .manage(Arc::clone(&WS_ANONYMOUS_SUBSCRIPTIONS))
         .attach(util::AppHeaders())
         .attach(util::Cors())
-        .attach(util::BetterLogging(extra_debug))
-        .ignite()
-        .await?;
+        .attach(util::BetterLogging(extra_debug));
+
+    // Attach metrics fairing if metrics are enabled
+    if CONFIG.enable_metrics() {
+        rocket_instance = rocket_instance.attach(api::MetricsFairing);
+    }
+
+    let instance = rocket_instance.ignite().await?;
 
     CONFIG.set_rocket_shutdown_handle(instance.shutdown());
 
diff --git a/src/metrics.rs b/src/metrics.rs
new file mode 100644
index 00000000..8a486dbb
--- /dev/null
+++ b/src/metrics.rs
@@ -0,0 +1,456 @@
+use std::time::SystemTime;
+
+#[cfg(feature = "enable_metrics")]
+use once_cell::sync::Lazy;
+#[cfg(feature = "enable_metrics")]
+use prometheus::{
+    register_gauge_vec, register_histogram_vec, register_int_counter_vec, register_int_gauge_vec, Encoder, GaugeVec,
+    HistogramVec, IntCounterVec, IntGaugeVec, TextEncoder,
+};
+
+use crate::{db::DbConn, error::Error};
+#[cfg(feature = "enable_metrics")]
+use crate::CONFIG;
+#[cfg(feature = "enable_metrics")]
+use std::sync::RwLock;
+#[cfg(feature = "enable_metrics")]
+use std::time::UNIX_EPOCH;
+
+// HTTP request metrics
+#[cfg(feature = "enable_metrics")]
+static HTTP_REQUESTS_TOTAL: Lazy<IntCounterVec> = Lazy::new(|| {
+    register_int_counter_vec!(
+        "vaultwarden_http_requests_total",
+        "Total number of HTTP requests processed",
+        &["method", "path", "status"]
+    )
+    .unwrap()
+});
+
+#[cfg(feature = "enable_metrics")]
+static HTTP_REQUEST_DURATION_SECONDS: Lazy<HistogramVec> = Lazy::new(|| {
+    register_histogram_vec!(
+        "vaultwarden_http_request_duration_seconds",
+        "HTTP request duration in seconds",
+        &["method", "path"],
+        vec![0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10.0]
+    )
+    .unwrap()
+});
+
+// Database metrics
+#[cfg(feature = "enable_metrics")]
+static DB_CONNECTIONS_ACTIVE: Lazy<IntGaugeVec> = Lazy::new(|| {
+    register_int_gauge_vec!("vaultwarden_db_connections_active", "Number of active database connections", &["database"])
+        .unwrap()
+});
+
+#[cfg(feature = "enable_metrics")]
+static DB_CONNECTIONS_IDLE: Lazy<IntGaugeVec> = Lazy::new(|| {
+    register_int_gauge_vec!("vaultwarden_db_connections_idle", "Number of idle database connections", &["database"])
+        .unwrap()
+});
+
+// Authentication metrics
+#[cfg(feature = "enable_metrics")]
+static AUTH_ATTEMPTS_TOTAL: Lazy<IntCounterVec> = Lazy::new(|| {
+    register_int_counter_vec!(
+        "vaultwarden_auth_attempts_total",
+        "Total number of authentication attempts",
+        &["method", "status"]
+    )
+    .unwrap()
+});
+
+// Business metrics
+#[cfg(feature = "enable_metrics")]
+static USERS_TOTAL: Lazy<IntGaugeVec> =
+    Lazy::new(|| register_int_gauge_vec!("vaultwarden_users_total", "Total number of users", &["status"]).unwrap());
+
+#[cfg(feature = "enable_metrics")]
+static ORGANIZATIONS_TOTAL: Lazy<IntGaugeVec> = Lazy::new(|| {
+    register_int_gauge_vec!("vaultwarden_organizations_total", "Total number of organizations", &["status"]).unwrap()
+});
+
+#[cfg(feature = "enable_metrics")]
+static VAULT_ITEMS_TOTAL: Lazy<IntGaugeVec> = Lazy::new(|| {
+    register_int_gauge_vec!("vaultwarden_vault_items_total", "Total number of vault items", &["type", "organization"])
+        .unwrap()
+});
+
+#[cfg(feature = "enable_metrics")]
+static COLLECTIONS_TOTAL: Lazy<IntGaugeVec> = Lazy::new(|| {
+    register_int_gauge_vec!("vaultwarden_collections_total", "Total number of collections", &["organization"]).unwrap()
+});
+
+// System metrics
+#[cfg(feature = "enable_metrics")]
+static UPTIME_SECONDS: Lazy<GaugeVec> =
+    Lazy::new(|| register_gauge_vec!("vaultwarden_uptime_seconds", "Uptime in seconds", &["version"]).unwrap());
+
+#[cfg(feature = "enable_metrics")]
+static BUILD_INFO: Lazy<IntGaugeVec> = Lazy::new(|| {
+    register_int_gauge_vec!("vaultwarden_build_info", "Build information", &["version", "revision", "branch"]).unwrap()
+});
+
+/// Increment HTTP request counter
+#[cfg(feature = "enable_metrics")]
+pub fn increment_http_requests(method: &str, path: &str, status: u16) {
+    HTTP_REQUESTS_TOTAL.with_label_values(&[method, path, &status.to_string()]).inc();
+}
+
+/// Observe HTTP request duration
+#[cfg(feature = "enable_metrics")]
+pub fn observe_http_request_duration(method: &str, path: &str, duration_seconds: f64) {
+    HTTP_REQUEST_DURATION_SECONDS.with_label_values(&[method, path]).observe(duration_seconds);
+}
+
+/// Update database connection metrics
+#[cfg(feature = "enable_metrics")]
+pub fn update_db_connections(database: &str, active: i64, idle: i64) {
+    DB_CONNECTIONS_ACTIVE.with_label_values(&[database]).set(active);
+    DB_CONNECTIONS_IDLE.with_label_values(&[database]).set(idle);
+}
+
+/// Increment authentication attempts (success/failure tracking)
+/// Tracks authentication success/failure by method (password, client_credentials, SSO, etc.)
+/// Called from src/api/identity.rs login() after each authentication attempt
+#[cfg(feature = "enable_metrics")]
+pub fn increment_auth_attempts(method: &str, status: &str) {
+    AUTH_ATTEMPTS_TOTAL.with_label_values(&[method, status]).inc();
+}
+
+/// Cached business metrics data
+#[cfg(feature = "enable_metrics")]
+#[derive(Clone)]
+struct BusinessMetricsCache {
+    timestamp: u64,
+    users_enabled: i64,
+    users_disabled: i64,
+    organizations: i64,
+    vault_counts: std::collections::HashMap<(String, String), i64>,
+    collection_counts: std::collections::HashMap<String, i64>,
+}
+
+#[cfg(feature = "enable_metrics")]
+static BUSINESS_METRICS_CACHE: Lazy<RwLock<Option<BusinessMetricsCache>>> = Lazy::new(|| RwLock::new(None));
+
+/// Check if business metrics cache is still valid
+#[cfg(feature = "enable_metrics")]
+fn is_cache_valid() -> bool {
+    let cache_timeout = CONFIG.metrics_business_cache_seconds();
+    if let Ok(cache) = BUSINESS_METRICS_CACHE.read() {
+        if let Some(ref cached) = *cache {
+            let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs();
+            return now - cached.timestamp < cache_timeout;
+        }
+    }
+    false
+}
+
+/// Update cached business metrics
+#[cfg(feature = "enable_metrics")]
+fn update_cached_metrics(cache: BusinessMetricsCache) {
+    if let Ok(mut cached) = BUSINESS_METRICS_CACHE.write() {
+        *cached = Some(cache);
+    }
+}
+
+/// Apply cached metrics to Prometheus gauges
+#[cfg(feature = "enable_metrics")]
+fn apply_cached_metrics(cache: &BusinessMetricsCache) {
+    USERS_TOTAL.with_label_values(&["enabled"]).set(cache.users_enabled);
+    USERS_TOTAL.with_label_values(&["disabled"]).set(cache.users_disabled);
+    ORGANIZATIONS_TOTAL.with_label_values(&["active"]).set(cache.organizations);
+
+    for ((cipher_type, org_label), count) in &cache.vault_counts {
+        VAULT_ITEMS_TOTAL.with_label_values(&[cipher_type, org_label]).set(*count);
+    }
+
+    for (org_id, count) in &cache.collection_counts {
+        COLLECTIONS_TOTAL.with_label_values(&[org_id]).set(*count);
+    }
+}
+
+/// Update business metrics from database (with caching)
+#[cfg(feature = "enable_metrics")]
+pub async fn update_business_metrics(conn: &mut DbConn) -> Result<(), Error> {
+    // Check if cache is still valid
+    if is_cache_valid() {
+        // Apply cached metrics without DB query
+        if let Ok(cache) = BUSINESS_METRICS_CACHE.read() {
+            if let Some(ref cached) = *cache {
+                apply_cached_metrics(cached);
+                return Ok(());
+            }
+        }
+    }
+
+    use crate::db::models::*;
+    use std::collections::HashMap;
+
+    // Count users
+    let enabled_users = User::count_enabled(conn).await;
+    let disabled_users = User::count_disabled(conn).await;
+
+    // Count organizations
+    let organizations_vec = Organization::get_all(conn).await;
+    let active_orgs = organizations_vec.len() as i64;
+
+    // Count vault items by type and organization
+    let vault_counts = Cipher::count_by_type_and_org(conn).await;
+
+    // Count collections per organization
+    let mut collection_counts: HashMap<String, i64> = HashMap::new();
+    for org in &organizations_vec {
+        let count = Collection::count_by_org(&org.uuid, conn).await;
+        collection_counts.insert(org.uuid.to_string(), count);
+    }
+
+    // Create cache entry
+    let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs();
+    let cache = BusinessMetricsCache {
+        timestamp: now,
+        users_enabled: enabled_users,
+        users_disabled: disabled_users,
+        organizations: active_orgs,
+        vault_counts,
+        collection_counts,
+    };
+
+    // Update cache and apply metrics
+    update_cached_metrics(cache.clone());
+    apply_cached_metrics(&cache);
+
+    Ok(())
+}
+
+/// Initialize build info metrics
+#[cfg(feature = "enable_metrics")]
+pub fn init_build_info() {
+    let version = crate::VERSION.unwrap_or("unknown");
+    BUILD_INFO.with_label_values(&[version, "unknown", "unknown"]).set(1);
+}
+
+/// Update system uptime
+#[cfg(feature = "enable_metrics")]
+pub fn update_uptime(start_time: SystemTime) {
+    if let Ok(elapsed) = start_time.elapsed() {
+        let version = crate::VERSION.unwrap_or("unknown");
+        UPTIME_SECONDS.with_label_values(&[version]).set(elapsed.as_secs_f64());
+    }
+}
+
+/// Gather all metrics and return as Prometheus text format
+#[cfg(feature = "enable_metrics")]
+pub fn gather_metrics() -> Result<String, Error> {
+    let encoder = TextEncoder::new();
+    let metric_families = prometheus::gather();
+    let mut output = Vec::new();
+    if let Err(e) = encoder.encode(&metric_families, &mut output) {
+        return Err(Error::new(format!("Failed to encode metrics: {}", e), ""));
+    }
+    match String::from_utf8(output) {
+        Ok(s) => Ok(s),
+        Err(e) => Err(Error::new(format!("Failed to convert metrics to string: {}", e), "")),
+    }
+}
+
+// No-op implementations when metrics are disabled
+#[cfg(not(feature = "enable_metrics"))]
+#[allow(dead_code)]
+pub fn increment_http_requests(_method: &str, _path: &str, _status: u16) {}
+
+#[cfg(not(feature = "enable_metrics"))]
+#[allow(dead_code)]
+pub fn observe_http_request_duration(_method: &str, _path: &str, _duration_seconds: f64) {}
+
+#[cfg(not(feature = "enable_metrics"))]
+#[allow(dead_code)]
+pub fn update_db_connections(_database: &str, _active: i64, _idle: i64) {}
+
+#[cfg(not(feature = "enable_metrics"))]
+pub fn increment_auth_attempts(_method: &str, _status: &str) {}
+
+#[cfg(not(feature = "enable_metrics"))]
+pub async fn update_business_metrics(_conn: &mut DbConn) -> Result<(), Error> {
+    Ok(())
+}
+
+#[cfg(not(feature = "enable_metrics"))]
+pub fn init_build_info() {}
+
+#[cfg(not(feature = "enable_metrics"))]
+#[allow(dead_code)]
+pub fn update_uptime(_start_time: SystemTime) {}
+
+#[cfg(not(feature = "enable_metrics"))]
+pub fn gather_metrics() -> Result<String, Error> {
+    Ok("Metrics not enabled".to_string())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[cfg(feature = "enable_metrics")]
+    mod metrics_enabled_tests {
+        use super::*;
+
+        #[test]
+        fn test_http_metrics_collection() {
+            increment_http_requests("GET", "/api/sync", 200);
+            increment_http_requests("POST", "/api/accounts/register", 201);
+            increment_http_requests("GET", "/api/sync", 500);
+            observe_http_request_duration("GET", "/api/sync", 0.150);
+            observe_http_request_duration("POST", "/api/accounts/register", 0.300);
+
+            let metrics = gather_metrics().expect("Failed to gather metrics");
+            assert!(metrics.contains("vaultwarden_http_requests_total"));
+            assert!(metrics.contains("vaultwarden_http_request_duration_seconds"));
+        }
+
+        #[test]
+        fn test_database_metrics_collection() {
+            update_db_connections("sqlite", 5, 10);
+            update_db_connections("postgresql", 8, 2);
+
+            let metrics = gather_metrics().expect("Failed to gather metrics");
+            assert!(metrics.contains("vaultwarden_db_connections_active"));
+            assert!(metrics.contains("vaultwarden_db_connections_idle"));
+        }
+
+        #[test]
+        fn test_authentication_metrics() {
+            increment_auth_attempts("password", "success");
+            increment_auth_attempts("password", "failed");
+            increment_auth_attempts("webauthn", "success");
+
+            let metrics = gather_metrics().expect("Failed to gather metrics");
+            assert!(metrics.contains("vaultwarden_auth_attempts_total"));
+            assert!(metrics.contains("method=\"password\""));
+            assert!(metrics.contains("status=\"success\""));
+            assert!(metrics.contains("status=\"failed\""));
+        }
+
+        #[test]
+        fn test_build_info_initialization() {
+            init_build_info();
+            let start_time = SystemTime::now();
+            update_uptime(start_time);
+
+            let metrics = gather_metrics().expect("Failed to gather metrics");
+            assert!(metrics.contains("vaultwarden_build_info"));
+            assert!(metrics.contains("vaultwarden_uptime_seconds"));
+        }
+
+        #[test]
+        fn test_metrics_gathering() {
+            increment_http_requests("GET", "/api/sync", 200);
+            update_db_connections("sqlite", 1, 5);
+            init_build_info();
+
+            let metrics_output = gather_metrics();
+            assert!(metrics_output.is_ok(), "gather_metrics should succeed");
+
+            let metrics_text = metrics_output.unwrap();
+            assert!(!metrics_text.is_empty(), "metrics output should not be empty");
+            assert!(metrics_text.contains("# HELP"), "metrics should have HELP lines");
+            assert!(metrics_text.contains("# TYPE"), "metrics should have TYPE lines");
+            assert!(metrics_text.contains("vaultwarden_"), "metrics should contain vaultwarden prefix");
+        }
+
+        #[tokio::test]
+        async fn test_business_metrics_collection_noop() {
+            init_build_info();
+            let metrics = gather_metrics().expect("Failed to gather metrics");
+            assert!(metrics.contains("vaultwarden_"), "Business metrics should be accessible");
+        }
+
+        #[test]
+        fn test_path_normalization() {
+            increment_http_requests("GET", "/api/sync", 200);
+            increment_http_requests("GET", "/api/accounts/123/profile", 200);
+            increment_http_requests("POST", "/api/organizations/456/users", 201);
+            increment_http_requests("PUT", "/api/ciphers/789", 200);
+
+            let result = gather_metrics();
+            assert!(result.is_ok(), "gather_metrics should succeed with various paths");
+
+            let metrics_text = result.unwrap();
+            assert!(!metrics_text.is_empty(), "metrics output should not be empty");
+            assert!(metrics_text.contains("vaultwarden_http_requests_total"), "should have http request metrics");
+        }
+
+        #[test]
+        fn test_concurrent_metrics_collection() {
+            use std::thread;
+
+            let handles: Vec<_> = (0..10).map(|i| {
+                thread::spawn(move || {
+                    increment_http_requests("GET", "/api/sync", 200);
+                    observe_http_request_duration("GET", "/api/sync", 0.1 + (i as f64 * 0.01));
+                    update_db_connections("sqlite", i, 10 - i);
+                })
+            }).collect();
+
+            for handle in handles {
+                handle.join().expect("Thread panicked");
+            }
+
+            let result = gather_metrics();
+            assert!(result.is_ok(), "metrics collection should be thread-safe");
+            assert!(!result.unwrap().is_empty(), "concurrent access should not corrupt metrics");
+        }
+    }
+
+    #[cfg(not(feature = "enable_metrics"))]
+    mod metrics_disabled_tests {
+        use super::*;
+
+        #[test]
+        fn test_no_op_implementations() {
+            increment_http_requests("GET", "/api/sync", 200);
+            observe_http_request_duration("GET", "/api/sync", 0.150);
+            update_db_connections("sqlite", 5, 10);
+            increment_auth_attempts("password", "success");
+            init_build_info();
+
+            let start_time = SystemTime::now();
+            update_uptime(start_time);
+
+            let result = gather_metrics();
+            assert!(result.is_ok(), "disabled metrics should return ok");
+            assert_eq!(result.unwrap(), "Metrics not enabled", "should return disabled message");
+        }
+
+        #[tokio::test]
+        async fn test_business_metrics_no_op() {
+            let result = gather_metrics();
+            assert!(result.is_ok(), "disabled metrics should not panic");
+            assert_eq!(result.unwrap(), "Metrics not enabled", "should return disabled message");
+        }
+
+        #[test]
+        fn test_concurrent_no_op_calls() {
+            use std::thread;
+
+            let handles: Vec<_> = (0..5).map(|i| {
+                thread::spawn(move || {
+                    increment_http_requests("GET", "/test", 200);
+                    observe_http_request_duration("GET", "/test", 0.1);
+                    update_db_connections("test", i, 5 - i);
+                    increment_auth_attempts("password", "success");
+                })
+            }).collect();
+
+            for handle in handles {
+                handle.join().expect("Thread panicked");
+            }
+
+            let result = gather_metrics();
+            assert!(result.is_ok(), "disabled metrics should be thread-safe");
+            assert_eq!(result.unwrap(), "Metrics not enabled", "disabled metrics should always return same message");
+        }
+    }
+}
diff --git a/src/metrics_test.rs b/src/metrics_test.rs
new file mode 100644
index 00000000..c173d28a
--- /dev/null
+++ b/src/metrics_test.rs
@@ -0,0 +1,177 @@
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::time::Duration;
+    use tokio::time::sleep;
+
+    #[cfg(feature = "enable_metrics")]
+    mod metrics_enabled_tests {
+        use super::*;
+
+        #[test]
+        fn test_http_metrics_collection() {
+            increment_http_requests("GET", "/api/sync", 200);
+            increment_http_requests("POST", "/api/accounts/register", 201);
+            increment_http_requests("GET", "/api/sync", 500);
+            observe_http_request_duration("GET", "/api/sync", 0.150);
+            observe_http_request_duration("POST", "/api/accounts/register", 0.300);
+
+            let metrics = gather_metrics().expect("Failed to gather metrics");
+            assert!(metrics.contains("vaultwarden_http_requests_total"));
+            assert!(metrics.contains("vaultwarden_http_request_duration_seconds"));
+        }
+
+        #[test]
+        fn test_database_metrics_collection() {
+            update_db_connections("sqlite", 5, 10);
+            update_db_connections("postgresql", 8, 2);
+            observe_db_query_duration("select", 0.025);
+            observe_db_query_duration("insert", 0.045);
+            observe_db_query_duration("update", 0.030);
+
+            let metrics = gather_metrics().expect("Failed to gather metrics");
+            assert!(metrics.contains("vaultwarden_db_connections_active"));
+            assert!(metrics.contains("vaultwarden_db_connections_idle"));
+            assert!(metrics.contains("vaultwarden_db_query_duration_seconds"));
+        }
+
+        #[test]
+        fn test_authentication_metrics() {
+            increment_auth_attempts("password", "success");
+            increment_auth_attempts("password", "failed");
+            increment_auth_attempts("webauthn", "success");
+            increment_auth_attempts("2fa", "failed");
+            update_user_sessions("authenticated", 150);
+            update_user_sessions("anonymous", 5);
+
+            let metrics = gather_metrics().expect("Failed to gather metrics");
+            assert!(metrics.contains("vaultwarden_auth_attempts_total"));
+            assert!(metrics.contains("vaultwarden_user_sessions_active"));
+        }
+
+        #[test]
+        fn test_build_info_initialization() {
+            init_build_info();
+            let start_time = std::time::SystemTime::now();
+            update_uptime(start_time);
+
+            let metrics = gather_metrics().expect("Failed to gather metrics");
+            assert!(metrics.contains("vaultwarden_build_info"));
+            assert!(metrics.contains("vaultwarden_uptime_seconds"));
+        }
+
+        #[test]
+        fn test_metrics_gathering() {
+            increment_http_requests("GET", "/api/sync", 200);
+            update_db_connections("sqlite", 1, 5);
+            init_build_info();
+
+            let metrics_output = gather_metrics();
+            assert!(metrics_output.is_ok(), "gather_metrics should succeed");
+
+            let metrics_text = metrics_output.unwrap();
+            assert!(!metrics_text.is_empty(), "metrics output should not be empty");
+            assert!(metrics_text.contains("# HELP"), "metrics should have HELP lines");
+            assert!(metrics_text.contains("# TYPE"), "metrics should have TYPE lines");
+            assert!(metrics_text.contains("vaultwarden_"), "metrics should contain vaultwarden prefix");
+        }
+
+        #[tokio::test]
+        async fn test_business_metrics_collection_noop() {
+            // Business metrics require database access, which cannot be easily mocked in unit tests.
+            // This test verifies that the async function exists and can be called without panicking.
+            // Integration tests would provide database access and verify metrics are actually updated.
+            init_build_info();
+            let metrics = gather_metrics().expect("Failed to gather metrics");
+            assert!(metrics.contains("vaultwarden_"), "Business metrics should be accessible");
+        }
+
+        #[test]
+        fn test_path_normalization() {
+            increment_http_requests("GET", "/api/sync", 200);
+            increment_http_requests("GET", "/api/accounts/123/profile", 200);
+            increment_http_requests("POST", "/api/organizations/456/users", 201);
+            increment_http_requests("PUT", "/api/ciphers/789", 200);
+
+            let result = gather_metrics();
+            assert!(result.is_ok(), "gather_metrics should succeed with various paths");
+
+            let metrics_text = result.unwrap();
+            assert!(!metrics_text.is_empty(), "metrics output should not be empty");
+            assert!(metrics_text.contains("vaultwarden_http_requests_total"), "should have http request metrics");
+        }
+
+        #[test]
+        fn test_concurrent_metrics_collection() {
+            use std::thread;
+
+            let handles: Vec<_> = (0..10).map(|i| {
+                thread::spawn(move || {
+                    increment_http_requests("GET", "/api/sync", 200);
+                    observe_http_request_duration("GET", "/api/sync", 0.1 + (i as f64 * 0.01));
+                    update_db_connections("sqlite", i, 10 - i);
+                })
+            }).collect();
+
+            for handle in handles {
+                handle.join().expect("Thread panicked");
+            }
+
+            let result = gather_metrics();
+            assert!(result.is_ok(), "metrics collection should be thread-safe");
+            assert!(!result.unwrap().is_empty(), "concurrent access should not corrupt metrics");
+        }
+    }
+
+    #[cfg(not(feature = "enable_metrics"))]
+    mod metrics_disabled_tests {
+        use super::*;
+
+        #[test]
+        fn test_no_op_implementations() {
+            increment_http_requests("GET", "/api/sync", 200);
+            observe_http_request_duration("GET", "/api/sync", 0.150);
+            update_db_connections("sqlite", 5, 10);
+            observe_db_query_duration("select", 0.025);
+            increment_auth_attempts("password", "success");
+            update_user_sessions("authenticated", 150);
+            init_build_info();
+
+            let start_time = std::time::SystemTime::now();
+            update_uptime(start_time);
+
+            let result = gather_metrics();
+            assert!(result.is_ok(), "disabled metrics should return ok");
+            assert_eq!(result.unwrap(), "Metrics not enabled", "should return disabled message");
+        }
+
+        #[tokio::test]
+        async fn test_business_metrics_no_op() {
+            let result = gather_metrics();
+            assert!(result.is_ok(), "disabled metrics should not panic");
+            assert_eq!(result.unwrap(), "Metrics not enabled", "should return disabled message");
+        }
+
+        #[test]
+        fn test_concurrent_no_op_calls() {
+            use std::thread;
+
+            let handles: Vec<_> = (0..5).map(|i| {
+                thread::spawn(move || {
+                    increment_http_requests("GET", "/test", 200);
+                    observe_http_request_duration("GET", "/test", 0.1);
+                    update_db_connections("test", i, 5 - i);
+                    increment_auth_attempts("password", "success");
+                })
+            }).collect();
+
+            for handle in handles {
+                handle.join().expect("Thread panicked");
+            }
+
+            let result = gather_metrics();
+            assert!(result.is_ok(), "disabled metrics should be thread-safe");
+            assert_eq!(result.unwrap(), "Metrics not enabled", "disabled metrics should always return same message");
+        }
+    }
+}
\ No newline at end of file