diff --git a/packages/matrix/helpers/index.ts b/packages/matrix/helpers/index.ts
index 01b32c84cf..0996602148 100644
--- a/packages/matrix/helpers/index.ts
+++ b/packages/matrix/helpers/index.ts
@@ -12,10 +12,11 @@ import {
 } from '../docker/synapse';
 import { realmPassword } from './realm-credentials';
 import { appURL, BasicSQLExecutor, SQLExecutor } from './isolated-realm-server';
+import { isEnvironmentMode, getEnvironmentSlug } from './environment-config';
 import { APP_BOXEL_MESSAGE_MSGTYPE } from './matrix-constants';
 import { randomUUID } from 'crypto';
 
-export const testHost = 'http://localhost:4205/test';
+export const testHost = appURL;
 export const mailHost = 'http://localhost:5001';
 export const initialRoomName = 'New AI Assistant Chat';
 export const REGISTRATION_TOKEN = 'abc123';
@@ -107,15 +108,27 @@ async function registerRealmRedirect(
 }
 
 export async function setRealmRedirects(page: Page) {
+  let baseServerUrl: string;
+  let isolatedServerUrl: string;
+
+  if (isEnvironmentMode()) {
+    let slug = getEnvironmentSlug();
+    baseServerUrl = `http://realm-server.${slug}.localhost`;
+    isolatedServerUrl = `http://realm-matrix-test.${slug}.localhost`;
+  } else {
+    baseServerUrl = 'http://localhost:4201';
+    isolatedServerUrl = 'http://localhost:4205';
+  }
+
   await registerRealmRedirect(
     page,
-    'http://localhost:4201/skills/',
-    'http://localhost:4205/skills/',
+    `${baseServerUrl}/skills/`,
+    `${isolatedServerUrl}/skills/`,
   );
   await registerRealmRedirect(
     page,
-    'http://localhost:4201/base/',
-    'http://localhost:4205/base/',
+    `${baseServerUrl}/base/`,
+    `${isolatedServerUrl}/base/`,
   );
 }
 
diff --git a/packages/matrix/helpers/isolated-realm-server.ts b/packages/matrix/helpers/isolated-realm-server.ts
index 4db80a5c25..8acc50308e 100644
--- a/packages/matrix/helpers/isolated-realm-server.ts
+++ b/packages/matrix/helpers/isolated-realm-server.ts
@@ -6,6 +6,7 @@ import { ensureDirSync, copySync, readFileSync } from 'fs-extra';
 import { Pool } from 'pg';
 import { createServer as createNetServer, type AddressInfo } from 'net';
 import type { SynapseInstance } from '../docker/synapse';
+import { isEnvironmentMode, getEnvironmentSlug } from './environment-config';
 
 setGracefulCleanup();
 
@@ -18,7 +19,23 @@ const skillsRealmDir = resolve(
 );
 const baseRealmDir = resolve(join(__dirname, '..', '..', 'base'));
 const matrixDir = resolve(join(__dirname, '..'));
-export const appURL = 'http://localhost:4205/test';
+
+const ISOLATED_REALM_SERVICE = 'realm-matrix-test';
+const ISOLATED_WORKER_SERVICE = 'worker-matrix-test';
+const DEFAULT_REALM_PORT = 4205;
+
+function getRealmBaseURL(): string {
+  if (isEnvironmentMode()) {
+    return `http://${ISOLATED_REALM_SERVICE}.${getEnvironmentSlug()}.localhost`;
+  }
+  return `http://localhost:${DEFAULT_REALM_PORT}`;
+}
+
+export const realmDomain = isEnvironmentMode()
+  ? `${ISOLATED_REALM_SERVICE}.${getEnvironmentSlug()}.localhost`
+  : `localhost:${DEFAULT_REALM_PORT}`;
+
+export const appURL = `${getRealmBaseURL()}/test`;
 
 const DEFAULT_PRERENDER_PORT = 4231;
 
@@ -142,7 +159,11 @@ export async function startPrerenderServer(
     ...process.env,
     NODE_ENV: process.env.NODE_ENV ?? 'development',
     NODE_NO_WARNINGS: '1',
-    BOXEL_HOST_URL: process.env.HOST_URL ?? 'http://localhost:4200',
+    BOXEL_HOST_URL:
+      process.env.HOST_URL ??
+      (isEnvironmentMode()
+        ? `http://host.${getEnvironmentSlug()}.localhost`
+        : 'http://localhost:4200'),
   };
   let prerenderArgs = [
     '--transpileOnly',
@@ -216,6 +237,13 @@ export async function startServer({
   let testDBName = `test_db_${Math.floor(10000000 * Math.random())}`;
   let workerManagerPort = await findAvailablePort(4232);
 
+  let envMode = isEnvironmentMode();
+  let realmBaseURL = getRealmBaseURL();
+  let realmPort = envMode ? 0 : DEFAULT_REALM_PORT;
+  let realmDomain = envMode
+    ? `${ISOLATED_REALM_SERVICE}.${getEnvironmentSlug()}.localhost`
+    : `localhost:${DEFAULT_REALM_PORT}`;
+
   process.env.PGPORT = '5435';
   process.env.PGDATABASE = testDBName;
   process.env.NODE_NO_WARNINGS = '1';
@@ -236,13 +264,16 @@ export async function startServer({
     `--prerendererUrl='${prerenderURL}'`,
     `--migrateDB`,
 
-    `--fromUrl='http://localhost:4205/test/'`,
-    `--toUrl='http://localhost:4205/test/'`,
+    `--fromUrl='${realmBaseURL}/test/'`,
+    `--toUrl='${realmBaseURL}/test/'`,
   ];
   workerArgs = workerArgs.concat([
     `--fromUrl='https://cardstack.com/base/'`,
-    `--toUrl='http://localhost:4205/base/'`,
+    `--toUrl='${realmBaseURL}/base/'`,
   ]);
+  if (envMode) {
+    workerArgs.push(`--serviceName=${ISOLATED_WORKER_SERVICE}`);
+  }
 
   let workerManager = spawn('ts-node', workerArgs, {
     cwd: realmServerDir,
@@ -262,7 +293,7 @@ export async function startServer({
   let serverArgs = [
     `--transpileOnly`,
     'main',
-    `--port=4205`,
+    `--port=${realmPort}`,
     `--matrixURL='${matrixURL}'`,
     `--realmsRootPath='${dir.name}'`,
     `--workerManagerPort=${workerManagerPort}`,
@@ -271,21 +302,24 @@ export async function startServer({
 
     `--path='${testRealmDir}'`,
     `--username='test_realm'`,
-    `--fromUrl='http://localhost:4205/test/'`,
-    `--toUrl='http://localhost:4205/test/'`,
+    `--fromUrl='${realmBaseURL}/test/'`,
+    `--toUrl='${realmBaseURL}/test/'`,
   ];
   serverArgs = serverArgs.concat([
     `--username='skills_realm'`,
     `--path='${skillsRealmDir}'`,
-    `--fromUrl='http://localhost:4205/skills/'`,
-    `--toUrl='http://localhost:4205/skills/'`,
+    `--fromUrl='${realmBaseURL}/skills/'`,
+    `--toUrl='${realmBaseURL}/skills/'`,
   ]);
   serverArgs = serverArgs.concat([
     `--username='base_realm'`,
     `--path='${baseRealmDir}'`,
     `--fromUrl='https://cardstack.com/base/'`,
-    `--toUrl='http://localhost:4205/base/'`,
+    `--toUrl='${realmBaseURL}/base/'`,
   ]);
+  if (envMode) {
+    serverArgs.push(`--serviceName=${ISOLATED_REALM_SERVICE}`);
+  }
 
   console.log(`realm server database: ${testDBName}`);
 
@@ -294,8 +328,8 @@ export async function startServer({
     stdio: ['pipe', 'pipe', 'pipe', 'ipc'],
     env: {
       ...process.env,
-      PUBLISHED_REALM_BOXEL_SPACE_DOMAIN: 'localhost:4205',
-      PUBLISHED_REALM_BOXEL_SITE_DOMAIN: 'localhost:4205',
+      PUBLISHED_REALM_BOXEL_SPACE_DOMAIN: realmDomain,
+      PUBLISHED_REALM_BOXEL_SITE_DOMAIN: realmDomain,
     },
   });
   realmServer.unref();
diff --git a/packages/matrix/playwright.config.ts b/packages/matrix/playwright.config.ts
index adb4530187..a807d90c0e 100644
--- a/packages/matrix/playwright.config.ts
+++ b/packages/matrix/playwright.config.ts
@@ -1,4 +1,13 @@
 import { defineConfig, devices } from '@playwright/test';
+import { appURL } from './helpers/isolated-realm-server';
+import {
+  isEnvironmentMode,
+  getEnvironmentSlug,
+} from './helpers/environment-config';
+
+// In environment mode, the isolated realm server is behind Traefik on port 80.
+// In non-env mode, it listens directly on port 4205.
+let realmPort = isEnvironmentMode() ? 80 : 4205;
 
 /**
  * See https://playwright.dev/docs/test-configuration.
@@ -14,7 +23,7 @@ export default defineConfig({
   reporter: process.env.CI ? 'blob' : 'html',
   /* Shared settings for all the projects below. See https://playwright.dev/docs/api/class-testoptions. */
   use: {
-    baseURL: 'http://localhost:4205/test',
+    baseURL: appURL,
 
     /* Collect trace when retrying the failed test. See https://playwright.dev/docs/trace-viewer */
     trace: 'retry-with-trace',
@@ -35,7 +44,7 @@ export default defineConfig({
         launchOptions: {
           args: [
             // Simulate resolving a custom workspace domain to a realm server
-            '--host-resolver-rules=MAP published.realm 127.0.0.1:4205',
+            `--host-resolver-rules=MAP published.realm 127.0.0.1:${realmPort}`,
             // Allow iframe to request storage access depsite being considered insecure
             '--unsafely-treat-insecure-origin-as-secure=http://published.realm',
           ],
diff --git a/packages/matrix/tests/head-tags.spec.ts b/packages/matrix/tests/head-tags.spec.ts
index 391e9537aa..c05bc0a1de 100644
--- a/packages/matrix/tests/head-tags.spec.ts
+++ b/packages/matrix/tests/head-tags.spec.ts
@@ -1,7 +1,7 @@
 import { test, expect } from './fixtures';
 import type { Page } from '@playwright/test';
 import { randomUUID } from 'crypto';
-import { appURL } from '../helpers/isolated-realm-server';
+import { appURL, realmDomain } from '../helpers/isolated-realm-server';
 import {
   clearLocalStorage,
   createRealm,
@@ -82,7 +82,7 @@ test.describe('Head tags', () => {
   }) => {
     await publishDefaultRealm(page);
 
-    let publishedRealmURLString = `http://${user.username}.localhost:4205/new-workspace/index`;
+    let publishedRealmURLString = `http://${user.username}.${realmDomain}/new-workspace/index`;
 
     await page.goto(publishedRealmURLString);
 
@@ -270,7 +270,7 @@ test.describe('Head tags', () => {
     await page.locator('[data-test-publish-button]').click();
     await page.waitForSelector('[data-test-unpublish-button]');
 
-    let publishedRealmURL = `http://${user.username}.localhost:4205/${realmName}/`;
+    let publishedRealmURL = `http://${user.username}.${realmDomain}/${realmName}/`;
     let defaultCardURL = `${publishedRealmURL}default-head-card.json`;
 
     await page.goto(defaultCardURL);
diff --git a/packages/matrix/tests/host-mode.spec.ts b/packages/matrix/tests/host-mode.spec.ts
index 00c5316a63..15fcb79f72 100644
--- a/packages/matrix/tests/host-mode.spec.ts
+++ b/packages/matrix/tests/host-mode.spec.ts
@@ -6,7 +6,7 @@ import {
   postCardSource,
   waitUntil,
 } from '../helpers';
-import { appURL } from '../helpers/isolated-realm-server';
+import { appURL, realmDomain } from '../helpers/isolated-realm-server';
 import { randomUUID } from 'crypto';
 
 test.describe('Host mode', () => {
@@ -185,10 +185,10 @@ test.describe('Host mode', () => {
     await page.reload();
     await page.locator('[data-test-host-mode-isolated]').waitFor();
 
-    publishedRealmURL = `http://published.localhost:4205/${username}/${realmName}/`;
+    publishedRealmURL = `http://published.${realmDomain}/${username}/${realmName}/`;
 
     await page.evaluate(
-      async ({ realmURL, publishedRealmURL }) => {
+      async ({ realmURL, publishedRealmURL, serverOrigin }) => {
         let sessions = JSON.parse(
           window.localStorage.getItem('boxel-session') ?? '{}',
         );
@@ -197,7 +197,7 @@ test.describe('Host mode', () => {
           throw new Error(`No session token found for ${realmURL}`);
         }
 
-        let response = await fetch('http://localhost:4205/_publish-realm', {
+        let response = await fetch(`${serverOrigin}/_publish-realm`, {
           method: 'POST',
           headers: {
             Accept: 'application/json',
@@ -216,13 +216,13 @@ test.describe('Host mode', () => {
 
         return response.json();
       },
-      { realmURL, publishedRealmURL },
+      { realmURL, publishedRealmURL, serverOrigin: serverIndexUrl },
     );
 
     publishedCardURL = `${publishedRealmURL}index.json`;
     publishedWhitePaperCardURL = `${publishedRealmURL}white-paper.json`;
     publishedMyCardURL = `${publishedRealmURL}my-card.json`;
-    connectRouteURL = `http://localhost:4205/connect/${encodeURIComponent(
+    connectRouteURL = `${serverIndexUrl}/connect/${encodeURIComponent(
       publishedRealmURL,
     )}`;
 
@@ -322,7 +322,7 @@ test.describe('Host mode', () => {
     page,
   }) => {
     let response = await page.goto(
-      'http://localhost:4205/connect/http%3A%2F%2Fexample.com',
+      `${serverIndexUrl}/connect/http%3A%2F%2Fexample.com`,
     );
 
     expect(response?.status()).toBe(404);
diff --git a/packages/matrix/tests/publish-realm.spec.ts b/packages/matrix/tests/publish-realm.spec.ts
index 2d5e1eeed7..d1e63302ba 100644
--- a/packages/matrix/tests/publish-realm.spec.ts
+++ b/packages/matrix/tests/publish-realm.spec.ts
@@ -1,6 +1,6 @@
 import { test, expect } from './fixtures';
 import type { Page } from '@playwright/test';
-import { appURL } from '../helpers/isolated-realm-server';
+import { appURL, realmDomain } from '../helpers/isolated-realm-server';
 import {
   clearLocalStorage,
   createRealm,
@@ -60,11 +60,11 @@ test.describe('Publish realm', () => {
     await newTab.waitForLoadState();
 
     await expect(newTab).toHaveURL(
-      `http://${user.username}.localhost:4205/new-workspace/`,
+      `http://${user.username}.${realmDomain}/new-workspace/`,
     );
     await expect(
       newTab.locator(
-        `[data-test-card="http://${user.username}.localhost:4205/new-workspace/index"]`,
+        `[data-test-card="http://${user.username}.${realmDomain}/new-workspace/index"]`,
       ),
     ).toBeVisible();
     await newTab.close();
@@ -119,11 +119,11 @@ test.describe('Publish realm', () => {
     await newTab.waitForLoadState();
 
     await expect(newTab).toHaveURL(
-      'http://acceptable-subdomain.localhost:4205/',
+      `http://acceptable-subdomain.${realmDomain}/`,
     );
     await expect(
       newTab.locator(
-        '[data-test-card="http://acceptable-subdomain.localhost:4205/index"]',
+        `[data-test-card="http://acceptable-subdomain.${realmDomain}/index"]`,
       ),
     ).toBeVisible();
     await newTab.close();
@@ -251,7 +251,7 @@ test.describe('Publish realm', () => {
     await newTab.waitForLoadState();
 
     await expect(newTab).toHaveURL(
-      `http://${user.username}.localhost:4205/new-workspace/`,
+      `http://${user.username}.${realmDomain}/new-workspace/`,
     );
     await newTab.close();
     await page.bringToFront();
@@ -281,7 +281,7 @@ test.describe('Publish realm', () => {
     await newTab.waitForLoadState();
 
     await expect(newTab).toHaveURL(
-      `http://${user.username}.localhost:4205/new-workspace/`,
+      `http://${user.username}.${realmDomain}/new-workspace/`,
     );
     await newTab.close();
     await page.bringToFront();
diff --git a/packages/matrix/tests/registration-with-token.spec.ts b/packages/matrix/tests/registration-with-token.spec.ts
index 498b60faa3..0f6afc8831 100644
--- a/packages/matrix/tests/registration-with-token.spec.ts
+++ b/packages/matrix/tests/registration-with-token.spec.ts
@@ -253,7 +253,7 @@ test.describe('User Registration w/ Token', () => {
       APP_BOXEL_REALMS_EVENT_TYPE,
     );
     expect(realms).toEqual({
-      realms: [`http://localhost:4205/${firstUser.username}/personal/`],
+      realms: [`${serverIndexUrl}/${firstUser.username}/personal/`],
     });
   });
 
diff --git a/packages/matrix/tests/skills.spec.ts b/packages/matrix/tests/skills.spec.ts
index 629d521d22..bac4349aed 100644
--- a/packages/matrix/tests/skills.spec.ts
+++ b/packages/matrix/tests/skills.spec.ts
@@ -50,15 +50,15 @@ test.describe('Skills', () => {
     ).toContainClass('checked');
   }
 
-  const environmentSkillCardId = `http://localhost:4205/skills/Skill/boxel-environment`;
+  const serverIndexUrl = new URL(appURL).origin;
+  const environmentSkillCardId = `${serverIndexUrl}/skills/Skill/boxel-environment`;
   const defaultSkillCardsForCodeMode = [
-    `http://localhost:4205/skills/Skill/boxel-development`,
+    `${serverIndexUrl}/skills/Skill/boxel-development`,
     environmentSkillCardId,
   ];
   const skillCard1 = `${appURL}/skill-pirate-speak`;
   const skillCard2 = `${appURL}/skill-seo`;
   const skillCard3 = `${appURL}/skill-card-title-editing`;
-  const serverIndexUrl = new URL(appURL).origin;
 
   test(`it can attach skill cards and toggle activation`, async ({ page }) => {
     await login(page, firstUser.username, firstUser.password, { url: appURL });
diff --git a/packages/realm-server/scripts/start-base.sh b/packages/realm-server/scripts/start-base.sh
index 034133a85e..2f9a73ee0b 100755
--- a/packages/realm-server/scripts/start-base.sh
+++ b/packages/realm-server/scripts/start-base.sh
@@ -1,7 +1,9 @@
 #! /bin/sh
 SCRIPTS_DIR="$(cd "$(dirname "$0")" && pwd)"
 . "$SCRIPTS_DIR/wait-for-pg.sh"
+. "$SCRIPTS_DIR/ensure-traefik.sh"
 
+ensure_traefik
 wait_for_postgres
 
 if [ -z "$MATRIX_REGISTRATION_SHARED_SECRET" ]; then
@@ -9,27 +11,47 @@ if [ -z "$MATRIX_REGISTRATION_SHARED_SECRET" ]; then
   export MATRIX_REGISTRATION_SHARED_SECRET
 fi
 
-PRERENDER_URL="${PRERENDER_URL:-http://localhost:4221}"
+# Environment-mode configuration
+if [ -n "$BOXEL_ENVIRONMENT" ]; then
+  ENV_SLUG=$(echo "$BOXEL_ENVIRONMENT" | tr '[:upper:]' '[:lower:]' | sed 's|/|-|g; s|[^a-z0-9-]||g; s|-\+|-|g; s|^-\|-$||g')
+  REALM_BASE_URL="http://realm-server.${ENV_SLUG}.localhost"
+  REALM_PORT=0
+  REALMS_ROOT="./realms/${ENV_SLUG}"
+  PGDATABASE_VAL="boxel_${ENV_SLUG}"
+  MATRIX_URL_VAL="http://matrix.${ENV_SLUG}.localhost"
+  PRERENDER_URL="${PRERENDER_URL:-http://prerender.${ENV_SLUG}.localhost}"
+  WORKER_MANAGER_ARG="--workerManagerUrl=http://worker.${ENV_SLUG}.localhost"
+  # Ensure per-environment database exists
+  sh "$SCRIPTS_DIR/../../../scripts/ensure-branch-db.sh" "$ENV_SLUG"
+else
+  REALM_BASE_URL="http://localhost:4201"
+  REALM_PORT=4201
+  REALMS_ROOT="./realms/localhost_4201_base"
+  PGDATABASE_VAL="boxel_base"
+  MATRIX_URL_VAL="http://localhost:8008"
+  PRERENDER_URL="${PRERENDER_URL:-http://localhost:4221}"
+  WORKER_MANAGER_ARG="$1"
+fi
 
 NODE_ENV=development \
   NODE_NO_WARNINGS=1 \
   PGPORT=5435 \
-  PGDATABASE=boxel_base \
+  PGDATABASE="${PGDATABASE_VAL}" \
   REALM_SERVER_SECRET_SEED="mum's the word" \
   REALM_SECRET_SEED="shhh! it's a secret" \
   GRAFANA_SECRET="shhh! it's a secret" \
-  MATRIX_URL=http://localhost:8008 \
+  MATRIX_URL="${MATRIX_URL_VAL}" \
   REALM_SERVER_MATRIX_USERNAME=realm_server \
   ts-node \
   --transpileOnly main \
-  --port=4201 \
-  --matrixURL='http://localhost:8008' \
-  --realmsRootPath='./realms/localhost_4201_base' \
+  --port="${REALM_PORT}" \
+  --matrixURL="${MATRIX_URL_VAL}" \
+  --realmsRootPath="${REALMS_ROOT}" \
   --prerendererUrl="${PRERENDER_URL}" \
   --migrateDB \
-  $1 \
+  $WORKER_MANAGER_ARG \
   \
   --path='../base' \
   --username='base_realm' \
   --fromUrl='https://cardstack.com/base/' \
-  --toUrl='http://localhost:4201/base/'
+  --toUrl="${REALM_BASE_URL}/base/"
diff --git a/packages/realm-server/scripts/start-services-for-host-tests.sh b/packages/realm-server/scripts/start-services-for-host-tests.sh
index 6b734859b7..7368744a7f 100755
--- a/packages/realm-server/scripts/start-services-for-host-tests.sh
+++ b/packages/realm-server/scripts/start-services-for-host-tests.sh
@@ -46,6 +46,37 @@ done
 
 export CATALOG_REALM_PATH="$CATALOG_TEMP_PATH"
 
+# Environment-mode configuration
+if [ -n "$BOXEL_ENVIRONMENT" ]; then
+  . "$SCRIPTS_DIR/ensure-traefik.sh"
+  ensure_traefik
+
+  ENV_SLUG=$(echo "$BOXEL_ENVIRONMENT" | tr '[:upper:]' '[:lower:]' | sed 's|/|-|g; s|[^a-z0-9-]||g; s|-\+|-|g; s|^-\|-$||g')
+  REALM_HOST="realm-server.${ENV_SLUG}.localhost"
+  REALM_TEST_HOST="realm-test.${ENV_SLUG}.localhost"
+  READY_PATH="_readiness-check?acceptHeader=application%2Fvnd.api%2Bjson"
+
+  PHASE1_URLS="http-get://${REALM_HOST}/base/${READY_PATH}|http://matrix.${ENV_SLUG}.localhost|http://localhost:5001|http://icons.${ENV_SLUG}.localhost"
+  PHASE2_URLS="http-get://${REALM_TEST_HOST}/node-test/${READY_PATH}"
+
+  # Pre-setup: ensure Postgres, database, and migrations are ready before
+  # starting the realm server (follows the same pattern as start-all.sh).
+  REPO_ROOT="$(cd "$SCRIPTS_DIR/../../.." && pwd)"
+  export PGPORT="${PGPORT:-5435}"
+  export PGDATABASE="${PGDATABASE:-boxel_${ENV_SLUG}}"
+
+  ./scripts/start-pg.sh
+  echo "Waiting for Postgres to accept connections..."
+  until docker exec boxel-pg pg_isready -U postgres >/dev/null 2>&1; do sleep 1; done
+  "$REPO_ROOT/scripts/ensure-branch-db.sh" "$ENV_SLUG"
+  echo "Running database migrations..."
+  pnpm migrate
+  ./scripts/start-matrix.sh
+else
+  PHASE1_URLS="http-get://localhost:4201/base/_readiness-check?acceptHeader=application%2Fvnd.api%2Bjson|http://localhost:8008|http://localhost:5001|http://localhost:4206"
+  PHASE2_URLS="http-get://localhost:4202/node-test/_readiness-check?acceptHeader=application%2Fvnd.api%2Bjson"
+fi
+
 # Make host-test startup logs focus on indexing progress rather than per-request noise.
 HOST_TEST_LOG_LEVELS="${HOST_TEST_LOG_LEVELS:-*=info,realm:requests=warn,realm-index-updater=debug,index-runner=debug,index-perf=debug,index-writer=debug,worker=debug,worker-manager=debug}"
 SKIP_CATALOG="${SKIP_CATALOG:-}"
@@ -63,7 +94,7 @@ WAIT_ON_TIMEOUT=900000 \
   NODE_NO_WARNINGS=1 \
   start-server-and-test \
     'run-p -ln start:pg start:prerender-dev start:prerender-manager-dev start:matrix start:smtp start:worker-development start:development' \
-    'http-get://localhost:4201/base/_readiness-check?acceptHeader=application%2Fvnd.api%2Bjson|http://localhost:8008|http://localhost:5001|http://localhost:4206' \
+    "$PHASE1_URLS" \
     'run-p -ln start:worker-test start:test-realms' \
-    'http-get://localhost:4202/node-test/_readiness-check?acceptHeader=application%2Fvnd.api%2Bjson' \
+    "$PHASE2_URLS" \
     'wait'
diff --git a/packages/realm-server/scripts/start-services-for-matrix-tests.sh b/packages/realm-server/scripts/start-services-for-matrix-tests.sh
index 914abe5553..f0d817c044 100755
--- a/packages/realm-server/scripts/start-services-for-matrix-tests.sh
+++ b/packages/realm-server/scripts/start-services-for-matrix-tests.sh
@@ -1,13 +1,56 @@
 #! /bin/sh
+SCRIPTS_DIR="$(cd "$(dirname "$0")" && pwd)"
+
 pnpm --dir=../skills-realm skills:setup
+
 # There is a race condition starting up the servers that setting up the
 # submission realm triggers which triggers the start-development.sh script to
 # SIGTERM. currently we don't need the submission realm for host tests to
-# skipping that. but this issue needs to be fixed. 
+# skipping that. but this issue needs to be fixed.
 # ALSO i really think if we want a submission realm in our matrix tests then
 # we probably need to add that via the isolated realm server--not here...
+
+# Environment-mode configuration
+if [ -n "$BOXEL_ENVIRONMENT" ]; then
+  . "$SCRIPTS_DIR/ensure-traefik.sh"
+  ensure_traefik
+
+  ENV_SLUG=$(echo "$BOXEL_ENVIRONMENT" | tr '[:upper:]' '[:lower:]' | sed 's|/|-|g; s|[^a-z0-9-]||g; s|-\+|-|g; s|^-\|-$||g')
+  REALM_HOST="realm-server.${ENV_SLUG}.localhost"
+  READINESS_URL="http-get://${REALM_HOST}/base/_readiness-check?acceptHeader=application%2Fvnd.api%2Bjson"
+  ICONS_URL="http://icons.${ENV_SLUG}.localhost"
+
+  # Pre-setup: ensure Postgres, database, and migrations are ready before
+  # starting the realm server (follows the same pattern as start-all.sh).
+  REPO_ROOT="$(cd "$SCRIPTS_DIR/../../.." && pwd)"
+  export PGPORT="${PGPORT:-5435}"
+  export PGDATABASE="${PGDATABASE:-boxel_${ENV_SLUG}}"
+
+  ./scripts/start-pg.sh
+  echo "Waiting for Postgres to accept connections..."
+  until docker exec boxel-pg pg_isready -U postgres >/dev/null 2>&1; do sleep 1; done
+  "$REPO_ROOT/scripts/ensure-branch-db.sh" "$ENV_SLUG"
+  echo "Running database migrations..."
+  pnpm migrate
+  ./scripts/start-matrix.sh
+
+  # Start icons server in background (env-aware: dynamic port + Traefik registration).
+  # In non-env mode, icons is expected to be started externally (e.g. CI does this).
+  sh "$SCRIPTS_DIR/start-icons.sh" &
+  ICONS_PID=$!
+  cleanup_icons_server() {
+    if [ -n "$ICONS_PID" ]; then
+      kill "$ICONS_PID" >/dev/null 2>&1 || true
+    fi
+  }
+  trap cleanup_icons_server EXIT INT TERM
+else
+  READINESS_URL="http-get://localhost:4201/base/_readiness-check?acceptHeader=application%2Fvnd.api%2Bjson"
+  ICONS_URL="http://localhost:4206"
+fi
+
 WAIT_ON_TIMEOUT=600000 NODE_NO_WARNINGS=1 SKIP_SUBMISSION=true \
   start-server-and-test \
     'run-p -ln start:pg start:prerender-dev start:prerender-manager-dev start:worker-base start:base' \
-    'http-get://localhost:4201/base/_readiness-check?acceptHeader=application%2Fvnd.api%2Bjson|http://localhost:4206' \
+    "${READINESS_URL}|${ICONS_URL}" \
     'wait'
diff --git a/packages/realm-server/scripts/start-worker-base.sh b/packages/realm-server/scripts/start-worker-base.sh
index abe5b3a27e..188e520a60 100755
--- a/packages/realm-server/scripts/start-worker-base.sh
+++ b/packages/realm-server/scripts/start-worker-base.sh
@@ -2,24 +2,42 @@
 SCRIPTS_DIR="$(cd "$(dirname "$0")" && pwd)"
 . "$SCRIPTS_DIR/wait-for-pg.sh"
 . "$SCRIPTS_DIR/wait-for-prerender.sh"
+. "$SCRIPTS_DIR/ensure-traefik.sh"
 
+ensure_traefik
 wait_for_postgres
-PRERENDER_URL="${PRERENDER_URL:-http://localhost:4222}"
+
+# Environment-mode configuration
+if [ -n "$BOXEL_ENVIRONMENT" ]; then
+  ENV_SLUG=$(echo "$BOXEL_ENVIRONMENT" | tr '[:upper:]' '[:lower:]' | sed 's|/|-|g; s|[^a-z0-9-]||g; s|-\+|-|g; s|^-\|-$||g')
+  REALM_BASE_URL="http://realm-server.${ENV_SLUG}.localhost"
+  WORKER_PORT=0
+  PGDATABASE_VAL="boxel_${ENV_SLUG}"
+  PRERENDER_URL="${PRERENDER_URL:-http://prerender-mgr.${ENV_SLUG}.localhost}"
+  MATRIX_URL_VAL="http://matrix.${ENV_SLUG}.localhost"
+else
+  REALM_BASE_URL="http://localhost:4201"
+  WORKER_PORT=4213
+  PGDATABASE_VAL="boxel_base"
+  PRERENDER_URL="${PRERENDER_URL:-http://localhost:4222}"
+  MATRIX_URL_VAL="http://localhost:8008"
+fi
+
 wait_for_prerender "$PRERENDER_URL"
 
 NODE_ENV=development \
   NODE_NO_WARNINGS=1 \
   NODE_OPTIONS="${NODE_OPTIONS:---max-old-space-size=4096}" \
   PGPORT=5435 \
-  PGDATABASE=boxel_base \
+  PGDATABASE="${PGDATABASE_VAL}" \
   REALM_SECRET_SEED="shhh! it's a secret" \
   REALM_SERVER_MATRIX_USERNAME=realm_server \
   LOW_CREDIT_THRESHOLD=2000 \
   ts-node \
   --transpileOnly worker-manager \
-  --port=4213 \
-  --matrixURL='http://localhost:8008' \
+  --port="${WORKER_PORT}" \
+  --matrixURL="${MATRIX_URL_VAL}" \
   --prerendererUrl="${PRERENDER_URL}" \
   \
   --fromUrl='https://cardstack.com/base/' \
-  --toUrl='http://localhost:4201/base/'
+  --toUrl="${REALM_BASE_URL}/base/"