diff --git a/apps/backend/src/lib/config.tsx b/apps/backend/src/lib/config.tsx
index f6585f95d5..9c535d095c 100644
--- a/apps/backend/src/lib/config.tsx
+++ b/apps/backend/src/lib/config.tsx
@@ -1091,7 +1091,12 @@ import.meta.vitest?.test('setEnvironmentConfigOverride blocks writes for develop
 
   const developmentEnvironment = await import("./development-environment");
 
-  const isDevelopmentEnvironmentProjectSpy = vi.spyOn(developmentEnvironment, "isDevelopmentEnvironmentProject").mockResolvedValue(true);
+  // Spy on getEnvironmentConfigWriteBlockReason directly, because spying on
+  // isDevelopmentEnvironmentProject does not intercept intra-module calls
+  // (the function is called directly within the same module, not through
+  // the module namespace export).
+  const spy = vi.spyOn(developmentEnvironment, "getEnvironmentConfigWriteBlockReason")
+    .mockResolvedValue(DEVELOPMENT_ENVIRONMENT_ENV_CONFIG_BLOCKED_MESSAGE);
 
   try {
     await expect(setEnvironmentConfigOverride({
@@ -1100,7 +1105,7 @@ import.meta.vitest?.test('setEnvironmentConfigOverride blocks writes for develop
       environmentConfigOverride: {},
     })).rejects.toThrow(DEVELOPMENT_ENVIRONMENT_ENV_CONFIG_BLOCKED_MESSAGE);
   } finally {
-    isDevelopmentEnvironmentProjectSpy.mockRestore();
+    spy.mockRestore();
   }
 });
 
diff --git a/apps/backend/src/lib/email-queue-step.tsx b/apps/backend/src/lib/email-queue-step.tsx
index c2864d322b..09e857b2f2 100644
--- a/apps/backend/src/lib/email-queue-step.tsx
+++ b/apps/backend/src/lib/email-queue-step.tsx
@@ -734,7 +734,6 @@ async function processSingleEmail(context: TenancyProcessingContext, row: EmailO
         return;
       }
     }
-
     const result = getEnvBoolean("STACK_EMAIL_BRANCHING_DISABLE_QUEUE_SENDING")
       ? Result.error({ errorType: "email-sending-disabled", canRetry: false, message: "Email sending is disabled", rawError: new Error("Email sending is disabled") })
       : await lowLevelSendEmailDirectWithoutRetries({
@@ -745,7 +744,6 @@ async function processSingleEmail(context: TenancyProcessingContext, row: EmailO
         html: row.renderedHtml ?? undefined,
         text: row.renderedText ?? undefined,
       });
-
     if (result.status === "error") {
       const newAttemptCount = row.sendRetries + 1;
       const isAttemptsExhausted = result.error.canRetry && newAttemptCount >= MAX_SEND_ATTEMPTS;
diff --git a/apps/backend/vitest.config.ts b/apps/backend/vitest.config.ts
index c4b64b9f47..603a6454dd 100644
--- a/apps/backend/vitest.config.ts
+++ b/apps/backend/vitest.config.ts
@@ -7,7 +7,7 @@ export default mergeConfig(
   sharedConfig,
   defineConfig({
     test: {
-      testTimeout: 20000,
+      testTimeout: 60000,
       env: {
         ...loadEnv('', process.cwd(), ''),
         ...loadEnv('development', process.cwd(), ''),
diff --git a/apps/dashboard/src/app/(main)/(protected)/projects/[projectId]/widget-playground/page-client.tsx b/apps/dashboard/src/app/(main)/(protected)/projects/[projectId]/widget-playground/page-client.tsx
index 39f388efd7..bbedefbd7d 100644
--- a/apps/dashboard/src/app/(main)/(protected)/projects/[projectId]/widget-playground/page-client.tsx
+++ b/apps/dashboard/src/app/(main)/(protected)/projects/[projectId]/widget-playground/page-client.tsx
@@ -1630,9 +1630,9 @@ function Draggable(props: {
                 <div className="text-red-500 text-sm p-2 bg-red-500/10 font-mono whitespace-pre-wrap">
                   A runtime error occured while rendering this widget.<br />
                   <br />
-                  {props.reset && <button className="text-blue-500 hover:underline" onClick={() => {
-                    props.reset!();
-                  }}>Reload widget</button>}<br />
+                  <button className="text-blue-500 hover:underline" onClick={() => {
+                    props.reset();
+                  }}>Reload widget</button><br />
                   <br />
                   {errorToNiceString(props.error)}
                 </div>
diff --git a/apps/e2e/tests/backend/backend-helpers.ts b/apps/e2e/tests/backend/backend-helpers.ts
index d7c83aeecf..b0b1e02398 100644
--- a/apps/e2e/tests/backend/backend-helpers.ts
+++ b/apps/e2e/tests/backend/backend-helpers.ts
@@ -483,20 +483,22 @@ export namespace Auth {
           "headers": Headers { <some fields may have been hidden> },
         }
       `);
-      for (let i = 0; true; i++) {
+      const deadlineMs = 60_000;
+      const intervalMs = 500;
+      const deadline = performance.now() + deadlineMs;
+      while (true) {
         const messages = await mailbox.fetchMessages();
         const containsSubstring = messages.some(message => message.subject.includes("Sign in to") && message.body?.html.includes(response.body.nonce));
         if (containsSubstring) {
           break;
         }
-        await wait(100 + i * 20);
-        if (i >= 40) {
-          throw new StackAssertionError(`Sign-in code message not found after ${i} attempts`, {
+        if (performance.now() >= deadline) {
+          throw new StackAssertionError(`Sign-in code message not found within ${deadlineMs}ms`, {
             response,
             messages: messages.map(m => ({ ...m, body: m.body && omit(m.body, ["html"]) })),
-            outboxEmails: await getOutboxEmails(),
           });
         }
+        await wait(intervalMs);
       }
       return {
         sendSignInCodeResponse: response,
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/analytics-events.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/analytics-events.test.ts
index e2e0f09d73..3dd1311678 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/analytics-events.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/analytics-events.test.ts
@@ -171,11 +171,11 @@ it("stores $token-refresh data in snake_case without row identity fields", async
 it("cannot read events from other projects", async ({ expect }) => {
   await Project.createAndSwitch({ config: { magic_link_enabled: true } });
   const projectAKeys = backendContext.value.projectKeys;
-  await Auth.Otp.signIn();
+  await Auth.fastSignUp();
 
   // Switch to another project and generate its own event
   await Project.createAndSwitch({ config: { magic_link_enabled: true } });
-  const { userId: projectBUserId } = await Auth.Otp.signIn();
+  const { userId: projectBUserId } = await Auth.fastSignUp();
   const projectBResponse = await fetchEventsWithRetry({
     userId: projectBUserId,
     eventType: "$token-refresh",
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/auth/sessions/index.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/auth/sessions/index.test.ts
index 5766ecef34..479269e127 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/auth/sessions/index.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/auth/sessions/index.test.ts
@@ -263,12 +263,12 @@ it("cannot delete current session as client", async ({ expect }) => {
 });
 
 it("cannot read another user's sessions as client", async ({ expect }) => {
-  // Create first user and sign up
-  const user1 = await Auth.Password.signUpWithEmail();
+  // Create first user and sign up (skip email wait — not needed for this test)
+  const user1 = await Auth.Password.signUpWithEmail({ noWaitForEmail: true });
 
   // Create second user and sign up
   backendContext.set({ userAuth: null, mailbox: createMailbox() }); // Clear first user's auth
-  const user2 = await Auth.Password.signUpWithEmail();
+  const user2 = await Auth.Password.signUpWithEmail({ noWaitForEmail: true });
 
   // Try to read user1's sessions while authenticated as user2
   const listResponse = await niceBackendFetch("/api/v1/auth/sessions", {
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/emails/delivery-info.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/emails/delivery-info.test.ts
index c0faa3cb6c..ee06700311 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/emails/delivery-info.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/emails/delivery-info.test.ts
@@ -129,7 +129,7 @@ describe("with valid credentials", () => {
   });
 
   it("should track sent emails", async ({ expect }) => {
-    await Auth.Otp.signIn();
+    await Auth.fastSignUp();
     await Project.createAndSwitch({
       display_name: "Test Sent Stats Project",
       config: {
@@ -167,50 +167,32 @@ describe("with valid credentials", () => {
       }
     `);
 
-    // wait for the email to be processed
-    await wait(12_000);
-
-    const response = await niceBackendFetch("/api/v1/emails/delivery-info", {
-      method: "GET",
-      accessType: "server",
-    });
-
-    expect(response).toMatchInlineSnapshot(`
-      NiceResponse {
-        "status": 200,
-        "body": {
-          "capacity": {
-            "boost_expires_at": null,
-            "boost_multiplier": 1,
-            "is_boost_active": false,
-            "penalty_factor": 1,
-            "rate_per_second": 27.777779320987655,
-          },
-          "stats": {
-            "day": {
-              "bounced": 0,
-              "marked_as_spam": 0,
-              "sent": 1,
-            },
-            "hour": {
-              "bounced": 0,
-              "marked_as_spam": 0,
-              "sent": 1,
-            },
-            "month": {
-              "bounced": 0,
-              "marked_as_spam": 0,
-              "sent": 1,
-            },
-            "week": {
-              "bounced": 0,
-              "marked_as_spam": 0,
-              "sent": 1,
-            },
-          },
-        },
-        "headers": Headers { <some fields may have been hidden> },
+    // Poll until email stats are updated instead of a fixed wait
+    let response;
+    for (let i = 0; i < 30; i++) {
+      await wait(1_000);
+      response = await niceBackendFetch("/api/v1/emails/delivery-info", {
+        method: "GET",
+        accessType: "server",
+      });
+      if (response.status === 200 && response.body?.stats?.hour?.sent >= 1) {
+        break;
       }
-    `);
+    }
+
+    expect(response!.status).toBe(200);
+    const { stats, capacity } = response!.body;
+    expect(stats.hour.sent).toBe(1);
+    expect(stats.day.sent).toBe(1);
+    expect(stats.week.sent).toBe(1);
+    expect(stats.month.sent).toBe(1);
+    expect(stats.hour.bounced).toBe(0);
+    expect(stats.hour.marked_as_spam).toBe(0);
+    expect(capacity.is_boost_active).toBe(false);
+    expect(capacity.boost_expires_at).toBe(null);
+    expect(capacity.boost_multiplier).toBe(1);
+    expect(capacity.penalty_factor).toBe(1);
+    expect(capacity.rate_per_second).toBeGreaterThan(27);
+    expect(capacity.rate_per_second).toBeLessThan(28);
   });
 });
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/integrations/custom/projects/provision.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/integrations/custom/projects/provision.test.ts
index 331c48599e..cd71b2d406 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/integrations/custom/projects/provision.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/integrations/custom/projects/provision.test.ts
@@ -70,6 +70,7 @@ it("should be able to provision a new project if client details are correct", as
         "description": "Project created by an external integration",
         "display_name": "Test project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/integrations/neon/oauth-providers.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/integrations/neon/oauth-providers.test.ts
index 261f2f0199..7f3d3be281 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/integrations/neon/oauth-providers.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/integrations/neon/oauth-providers.test.ts
@@ -127,6 +127,7 @@ it("lists oauth providers", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/integrations/neon/projects/current.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/integrations/neon/projects/current.test.ts
index d3e6a268a1..527586e014 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/integrations/neon/projects/current.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/integrations/neon/projects/current.test.ts
@@ -40,6 +40,7 @@ it("get project details", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -98,6 +99,7 @@ it("creates and updates the basic project information of a project", async ({ ex
         "description": "Updated description",
         "display_name": "Updated Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": true,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -172,6 +174,7 @@ it("creates and updates the email config of a project", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/integrations/neon/projects/provision.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/integrations/neon/projects/provision.test.ts
index e67e4a0d29..5dc5e132db 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/integrations/neon/projects/provision.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/integrations/neon/projects/provision.test.ts
@@ -71,6 +71,7 @@ it("should be able to provision a new project if neon client details are correct
         "description": "Created with Neon",
         "display_name": "Test project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/internal-metrics.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/internal-metrics.test.ts
index 4ea0cb2257..cc33e34bb1 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/internal-metrics.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/internal-metrics.test.ts
@@ -173,7 +173,12 @@ it("should return metrics data with users", async ({ expect }) => {
   backendContext.set({ mailbox: mailboxes[2], ipData: { country: "CH", ipAddress: "127.0.0.1", city: "Zurich", region: "ZH", latitude: 47.3769, longitude: 8.5417, tzIdentifier: "Europe/Zurich" } });
   await Auth.Otp.signIn();
 
-  const response = await waitForMetricsToIncludeUsersByCountry({ countryCode: "CH", expectedCount: 1 });
+  const response = await waitForMetricsMatch(
+    false,
+    (r) =>
+      r.body?.users_by_country?.["CH"] === 1 &&
+      (r.body?.active_users_by_country?.["AQ"]?.length ?? 0) >= 2,
+  );
   expect(response).toMatchSnapshot(`metrics_result_with_users`);
 
   await ensureAnonymousUsersAreStillExcluded(response);
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/internal/config-local-emulator.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/internal/config-local-emulator.test.ts
index 1b52da14cb..f13c3435d3 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/internal/config-local-emulator.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/internal/config-local-emulator.test.ts
@@ -6,7 +6,7 @@ import { it } from "../../../../../helpers";
 import { backendContext, niceBackendFetch } from "../../../../backend-helpers";
 
 const isLocalEmulator = process.env.NEXT_PUBLIC_STACK_IS_LOCAL_EMULATOR === "true";
-const blockedMessage = "cannot be changed in the local emulator";
+const blockedMessage = "cannot be changed in a development environment";
 const localEmulatorProjectEndpoint = "/api/v1/internal/local-emulator/project";
 
 async function switchToLocalEmulatorProject() {
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/internal/projects.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/internal/projects.test.ts
index f29fa73ed6..b07a57e2c8 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/internal/projects.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/internal/projects.test.ts
@@ -106,6 +106,7 @@ it("creates a new project", async ({ expect }) => {
         "description": "",
         "display_name": "Test Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -163,6 +164,7 @@ it("creates a new project with different configurations", async ({ expect }) =>
         "description": "Test description",
         "display_name": "Test Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": true,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -222,6 +224,7 @@ it("creates a new project with different configurations", async ({ expect }) =>
         "description": "",
         "display_name": "Test Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -272,6 +275,7 @@ it("creates a new project with different configurations", async ({ expect }) =>
         "description": "",
         "display_name": "Test Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -336,6 +340,7 @@ it("creates a new project with different configurations", async ({ expect }) =>
         "description": "",
         "display_name": "Test Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -402,6 +407,7 @@ it("creates a new project with different configurations", async ({ expect }) =>
         "description": "",
         "display_name": "Test Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -451,6 +457,7 @@ it("lists the current projects after creating a new project", async ({ expect })
             "description": "",
             "display_name": "New Project",
             "id": "<stripped UUID>",
+            "is_development_environment": false,
             "is_production_mode": false,
             "logo_dark_mode_url": null,
             "logo_full_dark_mode_url": null,
@@ -506,6 +513,7 @@ it("verifies email_theme update persists", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -550,6 +558,7 @@ it("verifies email_theme update persists", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -604,6 +613,7 @@ it("updates trusted domains without modifying allow_localhost", async ({ expect
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -661,6 +671,7 @@ it("updates trusted domains without modifying allow_localhost", async ({ expect
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -735,6 +746,7 @@ it("lets user update logo_url to a valid image", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/internal/transactions-refund.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/internal/transactions-refund.test.ts
index 878c633385..7618608d23 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/internal/transactions-refund.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/internal/transactions-refund.test.ts
@@ -908,7 +908,7 @@ async function createLiveModeSubscriptionWithRenewal(): Promise<{
   };
 }
 
-it("refunds a renewal invoice (invoice_id path) without money or revoke — sourceTxnId is sub-renewal", async () => {
+it("refunds a renewal invoice (invoice_id path) without money or revoke — sourceTxnId is sub-renewal", { timeout: 120_000 }, async () => {
   const { subscriptionId, renewalInvoiceId } = await createLiveModeSubscriptionWithRenewal();
 
   // Use amount_usd=0 and end_action='at-period-end' to exercise the
@@ -964,7 +964,7 @@ it("refunds a renewal invoice (invoice_id path) without money or revoke — sour
   expect(refundRow).toBeDefined();
 });
 
-it("rejects end_action='now' when invoice_id targets a renewal invoice", async () => {
+it("rejects end_action='now' when invoice_id targets a renewal invoice", { timeout: 120_000 }, async () => {
   // The product grant lives on the sub-start txn, not on renewals — so a
   // revocation entry referencing a renewal would point at a non-existent
   // entry. Force admin to end-immediately against the start invoice (or the
@@ -987,7 +987,7 @@ it("rejects end_action='now' when invoice_id targets a renewal invoice", async (
   expect(refundRes.body.error).toMatch(/Cannot end product access immediately when refunding a renewal invoice/);
 });
 
-it("rejects refund with invoice_id that does not belong to the subscription", async () => {
+it("rejects refund with invoice_id that does not belong to the subscription", { timeout: 120_000 }, async () => {
   const { subscriptionId } = await createLiveModeSubscriptionWithRenewal();
   const unrelatedInvoiceId = randomUUID();
 
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/payments/items.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/payments/items.test.ts
index 7aa811e62c..6282fb2c3d 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/payments/items.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/payments/items.test.ts
@@ -383,12 +383,17 @@ it("allows team admins to be added when item quantity is increased", async ({ ex
     return mailbox;
   }));
 
+  // Pre-fetch all invitation emails in parallel to avoid sequential waits
+  const allInvitationMessages = await Promise.all(
+    mailboxes.map((mailbox) => mailbox.waitForMessagesWithSubject("join")),
+  );
+
   for (let i = 0; i < mailboxes.length; i++) {
     const mailbox = mailboxes[i];
     backendContext.set({ mailbox: mailbox });
     await Auth.fastSignUp();
 
-    const invitationMessages = await mailbox.waitForMessagesWithSubject("join");
+    const invitationMessages = allInvitationMessages[i];
     const acceptResponse = await niceBackendFetch("/api/v1/team-invitations/accept", {
       method: "POST",
       accessType: "client",
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/project-permissions.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/project-permissions.test.ts
index e2f9af65ea..5a041ffc92 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/project-permissions.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/project-permissions.test.ts
@@ -238,6 +238,7 @@ it("can customize default user permissions", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/projects.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/projects.test.ts
index c0616c9025..26107451a8 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/projects.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/projects.test.ts
@@ -99,6 +99,7 @@ it("creates and updates the basic project information of a project", async ({ ex
         "description": "Updated description",
         "display_name": "Updated Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": true,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -152,6 +153,7 @@ it("updates the basic project configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -210,6 +212,7 @@ it("updates the project domains configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -274,6 +277,7 @@ it("updates the project domains configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -332,6 +336,7 @@ it("should allow insecure HTTP connections if insecureHttp is true", async ({ ex
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -433,6 +438,7 @@ it("updates the project email configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -496,6 +502,7 @@ it("updates the project email configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -545,6 +552,7 @@ it("updates the project email configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -594,6 +602,7 @@ it("updates the project email configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -657,6 +666,7 @@ it("updates the project email configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -833,6 +843,7 @@ it("updates the project oauth configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -889,6 +900,7 @@ it("updates the project oauth configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -949,6 +961,7 @@ it("updates the project oauth configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -1004,6 +1017,7 @@ it("updates the project oauth configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -1074,6 +1088,7 @@ it("updates the project oauth configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
@@ -1144,6 +1159,7 @@ it("updates the project oauth configuration", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/session-replays.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/session-replays.test.ts
index 02d2b3c78c..826712a544 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/session-replays.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/session-replays.test.ts
@@ -810,7 +810,7 @@ it("admin events endpoint does not allow fetching a chunk via the wrong session
   await Project.updateConfig({ apps: { installed: { analytics: { enabled: true } } } });
 
   // session1: upload under first refresh token
-  await Auth.Otp.signIn();
+  await Auth.fastSignUp();
   const batchId = randomUUID();
   const upload1 = await uploadBatch({
     browserSessionId: randomUUID(),
@@ -823,7 +823,7 @@ it("admin events endpoint does not allow fetching a chunk via the wrong session
   const recording1 = upload1.body?.session_replay_id;
 
   // session2: upload under a different refresh token
-  await Auth.Otp.signIn();
+  await Auth.fastSignUp();
   const upload2 = await uploadBatch({
     browserSessionId: randomUUID(),
     batchId: randomUUID(),
@@ -971,12 +971,28 @@ async function listReplays(queryParams: Record<string, string> = {}) {
   });
 }
 
+async function listReplaysWithRetry(
+  queryParams: Record<string, string>,
+  predicate: (res: Awaited<ReturnType<typeof listReplays>>) => boolean,
+  options: { attempts?: number, delayMs?: number } = {},
+) {
+  const attempts = options.attempts ?? 30;
+  const delayMs = options.delayMs ?? 500;
+  let res = await listReplays(queryParams);
+  for (let i = 0; i < attempts; i++) {
+    if (predicate(res)) return res;
+    await wait(delayMs);
+    res = await listReplays(queryParams);
+  }
+  return res;
+}
+
 it("admin list session replays filters by user_ids", async ({ expect }) => {
   await Project.createAndSwitch({ config: { magic_link_enabled: true } });
   await Project.updateConfig({ apps: { installed: { analytics: { enabled: true } } } });
 
   // User A
-  const userA = await Auth.Otp.signIn();
+  const userA = await Auth.fastSignUp();
   const uploadA = await uploadBatch({
     browserSessionId: randomUUID(),
     batchId: randomUUID(),
@@ -987,8 +1003,7 @@ it("admin list session replays filters by user_ids", async ({ expect }) => {
   expect(uploadA.status).toBe(200);
 
   // User B
-  await bumpEmailAddress();
-  const userB = await Auth.Otp.signIn();
+  const userB = await Auth.fastSignUp();
   const uploadB = await uploadBatch({
     browserSessionId: randomUUID(),
     batchId: randomUUID(),
@@ -998,6 +1013,14 @@ it("admin list session replays filters by user_ids", async ({ expect }) => {
   });
   expect(uploadB.status).toBe(200);
 
+  // Wait for ClickHouse to ingest both replays before asserting filters
+  const resBoth = await listReplaysWithRetry(
+    { user_ids: `${userA.userId},${userB.userId}` },
+    (res) => res.status === 200 && res.body?.items?.length === 2,
+  );
+  expect(resBoth.status).toBe(200);
+  expect(resBoth.body?.items?.length).toBe(2);
+
   // Filter by user A only
   const resA = await listReplays({ user_ids: userA.userId });
   expect(resA.status).toBe(200);
@@ -1010,11 +1033,6 @@ it("admin list session replays filters by user_ids", async ({ expect }) => {
   expect(resB.body?.items?.length).toBe(1);
   expect(resB.body?.items?.[0]?.project_user?.id).toBe(userB.userId);
 
-  // Filter by both users
-  const resBoth = await listReplays({ user_ids: `${userA.userId},${userB.userId}` });
-  expect(resBoth.status).toBe(200);
-  expect(resBoth.body?.items?.length).toBe(2);
-
   // Filter by nonexistent user
   const resNone = await listReplays({ user_ids: randomUUID() });
   expect(resNone.status).toBe(200);
@@ -1183,7 +1201,7 @@ it("admin list session replays filters by click_count_min", async ({ expect }) =
   const now = Date.now();
 
   // Replay A: user with 3 clicks
-  await Auth.Otp.signIn();
+  await Auth.fastSignUp();
   const segmentIdA = randomUUID();
   const uploadA = await uploadBatch({
     browserSessionId: randomUUID(),
@@ -1222,8 +1240,7 @@ it("admin list session replays filters by click_count_min", async ({ expect }) =
   expect(eventBatchA.status).toBe(200);
 
   // Replay B: user with 1 click
-  await bumpEmailAddress();
-  await Auth.Otp.signIn();
+  await Auth.fastSignUp();
   const segmentIdB = randomUUID();
   const uploadB = await uploadBatch({
     browserSessionId: randomUUID(),
@@ -1246,21 +1263,20 @@ it("admin list session replays filters by click_count_min", async ({ expect }) =
   });
   expect(eventBatchB.status).toBe(200);
 
-  // Retry loop for ClickHouse eventual consistency
-  let foundOnlyA = false;
-  for (let i = 0; i < 15; i++) {
-    const res = await listReplays({ click_count_min: "2" });
-    expect(res.status).toBe(200);
-    if (res.body?.items?.length === 1 && res.body?.items?.[0]?.id === replayIdA) {
-      foundOnlyA = true;
-      break;
-    }
-    await wait(500);
-  }
-  expect(foundOnlyA).toBe(true);
+  // Wait for ClickHouse to ingest click events and replays
+  const resClickMin = await listReplaysWithRetry(
+    { click_count_min: "2" },
+    (res) => res.status === 200 && res.body?.items?.length === 1 && res.body?.items?.[0]?.id === replayIdA,
+  );
+  expect(resClickMin.status).toBe(200);
+  expect(resClickMin.body?.items?.length).toBe(1);
+  expect(resClickMin.body?.items?.[0]?.id).toBe(replayIdA);
 
   // click_count_min=0 should return both (no-op filter)
-  const resAll = await listReplays({ click_count_min: "0" });
+  const resAll = await listReplaysWithRetry(
+    { click_count_min: "0" },
+    (res) => res.status === 200 && (res.body?.items?.length ?? 0) >= 2,
+  );
   expect(resAll.status).toBe(200);
   expect(resAll.body?.items?.length).toBeGreaterThanOrEqual(2);
 });
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/team-permissions.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/team-permissions.test.ts
index e5cde06b38..fa7de78c07 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/team-permissions.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/team-permissions.test.ts
@@ -256,6 +256,7 @@ it("can customize default team permissions", async ({ expect }) => {
         "description": "",
         "display_name": "New Project",
         "id": "<stripped UUID>",
+        "is_development_environment": false,
         "is_production_mode": false,
         "logo_dark_mode_url": null,
         "logo_full_dark_mode_url": null,
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/token-refresh-events.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/token-refresh-events.test.ts
index d0223cd243..173db0b66c 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/token-refresh-events.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/token-refresh-events.test.ts
@@ -45,8 +45,8 @@ const fetchEventsWithRetry = async (
   params: { userId?: string, eventType?: string },
   options: { attempts?: number, delayMs?: number, expectedCount?: number } = {}
 ) => {
-  const attempts = options.attempts ?? 10;
-  const delayMs = options.delayMs ?? 300;
+  const attempts = options.attempts ?? 40;
+  const delayMs = options.delayMs ?? 500;
   const expectedCount = options.expectedCount ?? 1;
 
   let response = await queryEvents(params);
@@ -77,7 +77,7 @@ const expectExactlyNTokenRefreshEvents = async (
   // First, wait for events to appear
   const response = await fetchEventsWithRetry(
     { userId, eventType: "$token-refresh" },
-    { expectedCount, attempts: 15, delayMs: 300 }
+    { expectedCount }
   );
 
   if (response.status !== 200) {
@@ -322,7 +322,7 @@ it("multiple session refreshes create one event each", async ({ expect }) => {
   });
   await InternalApiKey.createAndSetProjectKeys();
 
-  const { userId } = await Auth.Otp.signIn();
+  const { userId } = await Auth.fastSignUp();
   await expectExactlyNTokenRefreshEvents(userId, 1, { projectId });
 
   // Refresh multiple times
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/unsubscribe-link.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/unsubscribe-link.test.ts
index 698190684d..ccd6c502e9 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/unsubscribe-link.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/unsubscribe-link.test.ts
@@ -93,6 +93,7 @@ it("unsubscribe link should not be sent for emails with transactional notificati
   await Project.createAndSwitch({
     display_name: "Test Successful Email Project",
     config: {
+      credential_enabled: true,
       email_config: {
         type: "standard",
         host: "localhost",
@@ -104,7 +105,7 @@ it("unsubscribe link should not be sent for emails with transactional notificati
       },
     },
   });
-  const { userId } = await Auth.Password.signUpWithEmail();
+  const { userId } = await Auth.Password.signUpWithEmail({ noWaitForEmail: true });
   const response = await niceBackendFetch(
     "/api/v1/emails/send-email",
     {