diff --git a/.github/workflows/_build_artifacts.yml b/.github/workflows/_build_artifacts.yml
index 0e470e850..18ba32bd4 100644
--- a/.github/workflows/_build_artifacts.yml
+++ b/.github/workflows/_build_artifacts.yml
@@ -173,6 +173,7 @@ jobs:
             image_name: http-test-server
     env:
       BINARY_DEST_PATH: ${{ matrix.name.artifact }}_${{ matrix.name.version }}_${{ matrix.arch.shortname }}
+      SENTRY_ENVIRONMENT: "production"
     outputs:
       client_image: ${{ steps.image-name.outputs.client_image }}
       relay_image: ${{ steps.image-name.outputs.relay_image }}
diff --git a/.github/workflows/_tauri.yml b/.github/workflows/_tauri.yml
index 8d41ef711..5997e140a 100644
--- a/.github/workflows/_tauri.yml
+++ b/.github/workflows/_tauri.yml
@@ -20,6 +20,7 @@ defaults:
 env:
   RUSTFLAGS: "-Dwarnings"
   RUSTDOCFLAGS: "-D warnings"
+  SENTRY_ENVIRONMENT: "production"
 
 jobs:
   build-gui:
diff --git a/rust/gui-client/src-common/src/controller.rs b/rust/gui-client/src-common/src/controller.rs
index 7cac429fb..92d0c2194 100644
--- a/rust/gui-client/src-common/src/controller.rs
+++ b/rust/gui-client/src-common/src/controller.rs
@@ -191,8 +191,11 @@ impl<I: GuiIntegration> Controller<I> {
         // Start telemetry
         {
             let environment = self.advanced_settings.api_url.to_string();
-            self.telemetry
-                .start(environment.clone(), firezone_telemetry::GUI_DSN);
+            self.telemetry.start(
+                &environment,
+                firezone_bin_shared::git_version!("gui-client-*"),
+                firezone_telemetry::GUI_DSN,
+            );
             self.ipc_client
                 .send_msg(&IpcClientMsg::StartTelemetry { environment })
                 .await?;
diff --git a/rust/gui-client/src-common/src/settings.rs b/rust/gui-client/src-common/src/settings.rs
index 9a54275ba..2a9b4d0ad 100644
--- a/rust/gui-client/src-common/src/settings.rs
+++ b/rust/gui-client/src-common/src/settings.rs
@@ -23,14 +23,14 @@ pub struct AdvancedSettings {
 #[cfg(debug_assertions)]
 mod defaults {
     pub(crate) const AUTH_BASE_URL: &str = "https://app.firez.one";
-    pub(crate) const API_URL: &str = "wss://api.firez.one";
+    pub(crate) const API_URL: &str = "wss://api.firez.one/";
     pub(crate) const LOG_FILTER: &str = "firezone_gui_client=debug,info";
 }
 
 #[cfg(not(debug_assertions))]
 mod defaults {
     pub(crate) const AUTH_BASE_URL: &str = "https://app.firezone.dev";
-    pub(crate) const API_URL: &str = "wss://api.firezone.dev";
+    pub(crate) const API_URL: &str = "wss://api.firezone.dev/";
     pub(crate) const LOG_FILTER: &str = "info";
 }
 
diff --git a/rust/gui-client/src-tauri/src/client.rs b/rust/gui-client/src-tauri/src/client.rs
index cbc04a972..408d240ce 100644
--- a/rust/gui-client/src-tauri/src/client.rs
+++ b/rust/gui-client/src-tauri/src/client.rs
@@ -60,7 +60,11 @@ pub(crate) fn run() -> Result<()> {
             // Can't check elevation here because the Windows CI is always elevated
             let settings = common::settings::load_advanced_settings().unwrap_or_default();
             let telemetry = telemetry::Telemetry::default();
-            telemetry.start(settings.api_url.to_string(), telemetry::GUI_DSN);
+            telemetry.start(
+                settings.api_url.as_ref(),
+                firezone_bin_shared::git_version!("gui-client-*"),
+                telemetry::GUI_DSN,
+            );
             // Don't fix the log filter for smoke tests
             let common::logging::Handles {
                 logger: _logger,
@@ -88,7 +92,11 @@ fn run_gui(cli: Cli) -> Result<()> {
     let mut settings = common::settings::load_advanced_settings().unwrap_or_default();
     let telemetry = telemetry::Telemetry::default();
     // In the future telemetry will be opt-in per organization, that's why this isn't just at the top of `main`
-    telemetry.start(settings.api_url.to_string(), telemetry::GUI_DSN);
+    telemetry.start(
+        settings.api_url.as_ref(),
+        firezone_bin_shared::git_version!("gui-client-*"),
+        telemetry::GUI_DSN,
+    );
     fix_log_filter(&mut settings)?;
     let common::logging::Handles {
         logger: _logger,
diff --git a/rust/headless-client/src/ipc_service.rs b/rust/headless-client/src/ipc_service.rs
index efd08f6e1..34731851d 100644
--- a/rust/headless-client/src/ipc_service.rs
+++ b/rust/headless-client/src/ipc_service.rs
@@ -498,9 +498,11 @@ impl<'a> Handler<'a> {
 
                 session.connlib.set_disabled_resources(disabled_resources);
             }
-            ClientMsg::StartTelemetry { environment } => self
-                .telemetry
-                .start(environment, firezone_telemetry::IPC_SERVICE_DSN),
+            ClientMsg::StartTelemetry { environment } => self.telemetry.start(
+                &environment,
+                firezone_bin_shared::git_version!("gui-client-*"),
+                firezone_telemetry::IPC_SERVICE_DSN,
+            ),
             ClientMsg::StopTelemetry => self.telemetry.stop(),
         }
         Ok(())
diff --git a/rust/headless-client/src/main.rs b/rust/headless-client/src/main.rs
index 4aef0af75..04b396888 100644
--- a/rust/headless-client/src/main.rs
+++ b/rust/headless-client/src/main.rs
@@ -52,7 +52,7 @@ struct Cli {
         long,
         hide = true,
         env = "FIREZONE_API_URL",
-        default_value = "wss://api.firezone.dev"
+        default_value = "wss://api.firezone.dev/"
     )]
     api_url: url::Url,
 
@@ -116,7 +116,11 @@ fn main() -> Result<()> {
     let token_env_var = cli.token.take().map(SecretString::from);
     let cli = cli;
     let telemetry = Telemetry::default();
-    telemetry.start(cli.api_url.to_string(), firezone_telemetry::HEADLESS_DSN);
+    telemetry.start(
+        cli.api_url.as_ref(),
+        firezone_bin_shared::git_version!("headless-client-*"),
+        firezone_telemetry::HEADLESS_DSN,
+    );
 
     // Docs indicate that `remove_var` should actually be marked unsafe
     // SAFETY: We haven't spawned any other threads, this code should be the first
@@ -382,10 +386,10 @@ mod tests {
     fn cli() {
         let exe_name = "firezone-headless-client";
 
-        let actual = Cli::try_parse_from([exe_name, "--api-url", "wss://api.firez.one"]).unwrap();
+        let actual = Cli::try_parse_from([exe_name, "--api-url", "wss://api.firez.one/"]).unwrap();
         assert_eq!(
             actual.api_url,
-            Url::parse("wss://api.firez.one").expect("Hard-coded URL should always be parsable")
+            Url::parse("wss://api.firez.one/").expect("Hard-coded URL should always be parsable")
         );
         assert!(!actual.check);
 
diff --git a/rust/telemetry/src/lib.rs b/rust/telemetry/src/lib.rs
index 0e87a35eb..6dfc343ee 100644
--- a/rust/telemetry/src/lib.rs
+++ b/rust/telemetry/src/lib.rs
@@ -42,22 +42,33 @@ impl Clone for Telemetry {
 }
 
 impl Telemetry {
-    pub fn start(&self, environment: String, dsn: Dsn) {
+    pub fn start(&self, api_url: &str, release: &'static str, dsn: Dsn) {
         // Since it's `arc_swap` and not `Option`, there is a TOCTOU here,
         // but in practice it should never trigger
         if self.inner.load().is_some() {
             return;
         }
+
+        // Can't use URLs as `environment` directly, because Sentry doesn't allow slashes in environments.
+        // <https://docs.sentry.io/platforms/rust/configuration/environments/>
+        let environment = match api_url {
+            "wss://api.firezone.dev/" => "production",
+            "wss://api.firez.one/" => "staging",
+            _ => "self-hosted",
+        };
+
         tracing::info!("Starting telemetry");
         let inner = sentry::init((
             dsn.0,
             sentry::ClientOptions {
                 environment: Some(environment.into()),
-                release: sentry::release_name!(),
+                // We can't get the release number ourselves because we don't know if we're embedded in a GUI Client or a Headless Client.
+                release: Some(release.into()),
                 traces_sample_rate: 1.0,
                 ..Default::default()
             },
         ));
+        sentry::configure_scope(|scope| scope.set_tag("api_url", api_url));
         self.inner.swap(Some(inner.into()));
         sentry::start_session();
     }
@@ -83,6 +94,8 @@ impl Telemetry {
 mod tests {
     use super::*;
 
+    const ENV: &str = "unit test";
+
     // To avoid problems with global mutable state, we run unrelated tests in the same test case.
     #[test]
     fn sentry() {
@@ -110,7 +123,7 @@ mod tests {
             // Expect no telemetry because the telemetry module needs to be enabled before it can do anything
             negative_error("X7X4CKH3");
 
-            tele.start("test".to_string(), HEADLESS_DSN);
+            tele.start("test", ENV, HEADLESS_DSN);
             // Expect telemetry because the user opted in.
             sentry::add_breadcrumb(sentry::Breadcrumb {
                 ty: "test_crumb".into(),
@@ -123,7 +136,7 @@ mod tests {
             // Expect no telemetry because the user opted back out.
             negative_error("2RSIYAPX");
 
-            tele.start("test".to_string(), HEADLESS_DSN);
+            tele.start("test", ENV, HEADLESS_DSN);
             // Cycle one more time to be sure.
             error("S672IOBZ");
             tele.stop();
@@ -137,12 +150,12 @@ mod tests {
             {
                 let tele = Telemetry::default();
                 negative_error("4H7HFTNX");
-                tele.start("test".to_string(), HEADLESS_DSN);
+                tele.start("test", ENV, HEADLESS_DSN);
             }
             {
                 negative_error("GF46D6IL");
                 let tele = Telemetry::default();
-                tele.start("test".to_string(), HEADLESS_DSN);
+                tele.start("test", ENV, HEADLESS_DSN);
                 error("OKOEUKSW");
             }
         }