diff --git a/apps/backend/package.json b/apps/backend/package.json
index ccf240188..12174e897 100644
--- a/apps/backend/package.json
+++ b/apps/backend/package.json
@@ -19,8 +19,8 @@
     "build-self-host-migration-script": "tsdown --config scripts/db-migrations.tsdown.config.ts",
     "analyze-bundle": "next experimental-analyze",
     "start": "next start --port ${NEXT_PUBLIC_HEXCLAVE_PORT_PREFIX:-81}02",
-    "codegen-prisma": "STACK_DATABASE_CONNECTION_STRING=\"${STACK_DATABASE_CONNECTION_STRING:-placeholder-database-connection-string}\" pnpm run prisma generate",
-    "codegen-prisma:watch": "STACK_DATABASE_CONNECTION_STRING=\"${STACK_DATABASE_CONNECTION_STRING:-placeholder-database-connection-string}\" pnpm run prisma generate --watch",
+    "codegen-prisma": "HEXCLAVE_DATABASE_CONNECTION_STRING=\"${HEXCLAVE_DATABASE_CONNECTION_STRING:-${STACK_DATABASE_CONNECTION_STRING:-placeholder-database-connection-string}}\" pnpm run prisma generate",
+    "codegen-prisma:watch": "HEXCLAVE_DATABASE_CONNECTION_STRING=\"${HEXCLAVE_DATABASE_CONNECTION_STRING:-${STACK_DATABASE_CONNECTION_STRING:-placeholder-database-connection-string}}\" pnpm run prisma generate --watch",
     "generate-private-sign-up-risk-engine": "pnpm run with-env tsx scripts/generate-private-sign-up-risk-engine.ts",
     "generate-private-sign-up-risk-engine:watch": "chokidar 'src/private/src/sign-up-risk-engine.ts' -c 'pnpm run generate-private-sign-up-risk-engine'",
     "codegen-route-info": "pnpm run with-env tsx scripts/generate-route-info.ts",
diff --git a/apps/backend/src/lib/bulldozer/db/index.fuzz.test.ts b/apps/backend/src/lib/bulldozer/db/index.fuzz.test.ts
index a508f3684..af96b120f 100644
--- a/apps/backend/src/lib/bulldozer/db/index.fuzz.test.ts
+++ b/apps/backend/src/lib/bulldozer/db/index.fuzz.test.ts
@@ -2,6 +2,7 @@ import { stringCompare } from "@hexclave/shared/dist/utils/strings";
 import postgres from "postgres";
 import { afterAll, afterEach, beforeAll, beforeEach, describe, expect, test } from "vitest";
 import type { Table } from "./index";
+import { resolveTestDatabaseConnectionString } from "./test-db-env";
 import type { RowData } from "./utilities";
 import {
   createBulldozerExecutionContext,
@@ -57,11 +58,7 @@ type TestDb = { full: string, base: string };
 const TEST_DB_PREFIX = "stack_bulldozer_db_fuzz_test";
 
 function getTestDbUrls(): TestDb {
-  const env = Reflect.get(import.meta, "env");
-  const connectionString = Reflect.get(env, "STACK_DATABASE_CONNECTION_STRING");
-  if (typeof connectionString !== "string" || connectionString.length === 0) {
-    throw new Error("Missing STACK_DATABASE_CONNECTION_STRING");
-  }
+  const connectionString = resolveTestDatabaseConnectionString();
   const base = connectionString.replace(/\/[^/]*(\?.*)?$/, "");
   const query = connectionString.split("?")[1] ?? "";
   const dbName = `${TEST_DB_PREFIX}_${Math.random().toString(16).slice(2, 12)}`;
diff --git a/apps/backend/src/lib/bulldozer/db/index.perf.test.ts b/apps/backend/src/lib/bulldozer/db/index.perf.test.ts
index 197fadec3..ba1592296 100644
--- a/apps/backend/src/lib/bulldozer/db/index.perf.test.ts
+++ b/apps/backend/src/lib/bulldozer/db/index.perf.test.ts
@@ -2,6 +2,7 @@ import { stringCompare } from "@hexclave/shared/dist/utils/strings";
 import postgres from "postgres";
 import { afterAll, afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
 import type { Table } from "./index";
+import { resolveTestDatabaseConnectionString } from "./test-db-env";
 import type { RowData } from "./utilities";
 import {
   createBulldozerExecutionContext,
@@ -112,11 +113,7 @@ const LOAD_REDUCE_TABLE_INIT_MAX_MS = withCiPerfHeadroom(90_000);
 const LOAD_REDUCE_TABLE_COUNT_QUERY_MAX_MS = withCiPerfHeadroom(8_000);
 
 function getTestDbUrls(): TestDb {
-  const env = Reflect.get(import.meta, "env");
-  const connectionString = Reflect.get(env, "STACK_DATABASE_CONNECTION_STRING");
-  if (typeof connectionString !== "string" || connectionString.length === 0) {
-    throw new Error("Missing STACK_DATABASE_CONNECTION_STRING");
-  }
+  const connectionString = resolveTestDatabaseConnectionString();
   const base = connectionString.replace(/\/[^/]*(\?.*)?$/, "");
   const query = connectionString.split("?")[1] ?? "";
   const dbName = `${TEST_DB_PREFIX}_${Math.random().toString(16).slice(2, 12)}`;
diff --git a/apps/backend/src/lib/bulldozer/db/index.test.ts b/apps/backend/src/lib/bulldozer/db/index.test.ts
index 5b2b2aa77..85d1ade17 100644
--- a/apps/backend/src/lib/bulldozer/db/index.test.ts
+++ b/apps/backend/src/lib/bulldozer/db/index.test.ts
@@ -2,6 +2,7 @@ import { stringCompare, templateIdentity } from "@hexclave/shared/dist/utils/str
 import postgres from "postgres";
 import { afterAll, afterEach, beforeAll, beforeEach, describe, expect, it, test } from "vitest";
 import type { Table } from "./index";
+import { resolveTestDatabaseConnectionString } from "./test-db-env";
 import {
   createBulldozerExecutionContext,
   declareCompactTable,
@@ -26,11 +27,7 @@ type TestDb = { full: string, base: string };
 const TEST_DB_PREFIX = "stack_bulldozer_db_test";
 
 function getTestDbUrls(): TestDb {
-  const env = Reflect.get(import.meta, "env");
-  const connectionString = Reflect.get(env, "STACK_DATABASE_CONNECTION_STRING");
-  if (typeof connectionString !== "string" || connectionString.length === 0) {
-    throw new Error("Missing STACK_DATABASE_CONNECTION_STRING");
-  }
+  const connectionString = resolveTestDatabaseConnectionString();
   const base = connectionString.replace(/\/[^/]*(\?.*)?$/, "");
   const query = connectionString.split("?")[1] ?? "";
   const dbName = `${TEST_DB_PREFIX}_${Math.random().toString(16).slice(2, 12)}`;
diff --git a/apps/backend/src/lib/bulldozer/db/test-db-env.ts b/apps/backend/src/lib/bulldozer/db/test-db-env.ts
new file mode 100644
index 000000000..ae8b4a597
--- /dev/null
+++ b/apps/backend/src/lib/bulldozer/db/test-db-env.ts
@@ -0,0 +1,24 @@
+/**
+ * Resolve the test database connection string from the environment, preferring
+ * the canonical `HEXCLAVE_DATABASE_CONNECTION_STRING` and falling back to the
+ * legacy `STACK_DATABASE_CONNECTION_STRING`. Empty counts as unset. Throws when
+ * both names are set to different non-empty values, or when neither is set.
+ *
+ * Shared by the bulldozer/payments DB-backed vitest suites so the dual-read
+ * stays consistent with the rest of the Hexclave rebrand.
+ */
+export function resolveTestDatabaseConnectionString(): string {
+  const env = Reflect.get(import.meta, "env");
+  const hexclaveRaw = Reflect.get(env, "HEXCLAVE_DATABASE_CONNECTION_STRING");
+  const stackRaw = Reflect.get(env, "STACK_DATABASE_CONNECTION_STRING");
+  const hexclaveValue = typeof hexclaveRaw === "string" && hexclaveRaw.length > 0 ? hexclaveRaw : undefined;
+  const stackValue = typeof stackRaw === "string" && stackRaw.length > 0 ? stackRaw : undefined;
+  if (hexclaveValue && stackValue && hexclaveValue !== stackValue) {
+    throw new Error("Environment variables HEXCLAVE_DATABASE_CONNECTION_STRING and STACK_DATABASE_CONNECTION_STRING are both set to different values. Remove one of them or set them to the same value.");
+  }
+  const value = hexclaveValue || stackValue;
+  if (!value) {
+    throw new Error("Missing environment variable HEXCLAVE_DATABASE_CONNECTION_STRING or STACK_DATABASE_CONNECTION_STRING.");
+  }
+  return value;
+}
diff --git a/apps/backend/src/lib/bulldozer/db/timefold-queue-downstream.test.ts b/apps/backend/src/lib/bulldozer/db/timefold-queue-downstream.test.ts
index f40379437..ef92b00f1 100644
--- a/apps/backend/src/lib/bulldozer/db/timefold-queue-downstream.test.ts
+++ b/apps/backend/src/lib/bulldozer/db/timefold-queue-downstream.test.ts
@@ -22,6 +22,7 @@ import {
   toQueryableSqlQuery,
 } from "./index";
 import { loadProcessQueueFunctionSql } from "./test-sql-loaders";
+import { resolveTestDatabaseConnectionString } from "./test-db-env";
 
 type SqlExpression<T> = { type: "expression", sql: string };
 type SqlStatement = { type: "statement", sql: string, outputName?: string };
@@ -42,11 +43,7 @@ function predicate(sql: string): SqlPredicate {
 const TEST_DB_PREFIX = "stack_bulldozer_queue_downstream_test";
 
 function getTestDbUrls() {
-  const env = Reflect.get(import.meta, "env");
-  const connectionString = Reflect.get(env, "STACK_DATABASE_CONNECTION_STRING");
-  if (typeof connectionString !== "string" || connectionString.length === 0) {
-    throw new Error("Missing STACK_DATABASE_CONNECTION_STRING");
-  }
+  const connectionString = resolveTestDatabaseConnectionString();
   const base = connectionString.replace(/\/[^/]*(\?.*)?$/, "");
   const query = connectionString.split("?")[1] ?? "";
   const dbName = `${TEST_DB_PREFIX}_${Math.random().toString(16).slice(2, 12)}`;
diff --git a/apps/backend/src/lib/payments/schema/__tests__/test-helpers.ts b/apps/backend/src/lib/payments/schema/__tests__/test-helpers.ts
index d9af185bf..07baf4eac 100644
--- a/apps/backend/src/lib/payments/schema/__tests__/test-helpers.ts
+++ b/apps/backend/src/lib/payments/schema/__tests__/test-helpers.ts
@@ -13,17 +13,13 @@ import {
   toQueryableSqlQuery,
 } from "@/lib/bulldozer/db/index";
 import { loadProcessQueueFunctionSql } from "@/lib/bulldozer/db/test-sql-loaders";
+import { resolveTestDatabaseConnectionString } from "@/lib/bulldozer/db/test-db-env";
 
 type SqlStatement = { type: "statement", sql: string, outputName?: string };
 type SqlQuery = { type: "query", sql: string, toStatement(outputName?: string): SqlStatement };
 
 function getConnectionString(): string {
-  const env = Reflect.get(import.meta, "env");
-  const connectionString = Reflect.get(env, "STACK_DATABASE_CONNECTION_STRING");
-  if (typeof connectionString !== "string" || connectionString.length === 0) {
-    throw new Error("Missing STACK_DATABASE_CONNECTION_STRING");
-  }
-  return connectionString;
+  return resolveTestDatabaseConnectionString();
 }
 
 export type CreateTestDbOptions = {
diff --git a/apps/backend/src/polyfills.tsx b/apps/backend/src/polyfills.tsx
index 7a4d65234..cdcaf77e1 100644
--- a/apps/backend/src/polyfills.tsx
+++ b/apps/backend/src/polyfills.tsx
@@ -22,7 +22,7 @@ const sentryErrorSink = (location: string, error: unknown, level: "error" | "war
 
 export function ensurePolyfilled() {
   for (const [key, value] of Object.entries(process.env)) {
-    if (key.startsWith("STACK_") || key.startsWith("NEXT_PUBLIC_STACK_")) {
+    if (key.startsWith("STACK_") || key.startsWith("NEXT_PUBLIC_STACK_") || key.startsWith("HEXCLAVE_") || key.startsWith("NEXT_PUBLIC_HEXCLAVE_")) {
       const replaced = expandHexclavePortPrefix(value ?? undefined);
       if (replaced !== undefined) {
         // eslint-disable-next-line no-restricted-syntax
diff --git a/apps/dashboard/.env b/apps/dashboard/.env
index 5378b0119..b99c169b0 100644
--- a/apps/dashboard/.env
+++ b/apps/dashboard/.env
@@ -12,9 +12,9 @@ NEXT_PUBLIC_HEXCLAVE_STRIPE_PUBLISHABLE_KEY=# enter your Stripe publishable key
 NEXT_PUBLIC_HEXCLAVE_SVIX_SERVER_URL=# For prod, leave it empty. For local development, use `http://localhost:8113`
 
 # Misc, optional
-NEXT_PUBLIC_HEXCLAVE_HEAD_TAGS='[{ "tagName": "script", "attributes": {}, "innerHTML": "// insert head tags here" }]'
+NEXT_PUBLIC_HEXCLAVE_HEAD_TAGS=# a JSON array of head tags to inject, e.g. '[{ "tagName": "script", "attributes": {}, "innerHTML": "..." }]'. Leave empty here so a platform-set legacy NEXT_PUBLIC_STACK_HEAD_TAGS value isn't treated as a conflict in prod builds.
 HEXCLAVE_DEVELOPMENT_TRANSLATION_LOCALE=# enter the locale to use for the translation provider here, for example: de-DE. Only works during development, not in production. Optional, by default don't translate
-NEXT_PUBLIC_HEXCLAVE_ENABLE_DEVELOPMENT_FEATURES_PROJECT_IDS='["internal"]'
+NEXT_PUBLIC_HEXCLAVE_ENABLE_DEVELOPMENT_FEATURES_PROJECT_IDS=# JSON array of project IDs that get development features (set to '["internal"]' in .env.development). Leave empty here so a platform-set legacy NEXT_PUBLIC_STACK_* value isn't treated as a conflict in prod builds.
 NEXT_PUBLIC_HEXCLAVE_DEBUGGER_ON_ASSERTION_ERROR=# set to true to open the debugger on assertion errors (set to true in .env.development)
 HEXCLAVE_FEATUREBASE_JWT_SECRET=# used for Featurebase SSO, you probably won't have to set this
 HEXCLAVE_CHANGELOG_URL=# Used for raw github link to root changelog.md file.
diff --git a/apps/dashboard/.env.development b/apps/dashboard/.env.development
index 8189e6966..3464e3957 100644
--- a/apps/dashboard/.env.development
+++ b/apps/dashboard/.env.development
@@ -11,5 +11,6 @@ NEXT_PUBLIC_HEXCLAVE_SVIX_SERVER_URL=http://localhost:${NEXT_PUBLIC_HEXCLAVE_POR
 HEXCLAVE_ARTIFICIAL_DEVELOPMENT_DELAY_MS=50
 
 NEXT_PUBLIC_HEXCLAVE_DEBUGGER_ON_ASSERTION_ERROR=false
+NEXT_PUBLIC_HEXCLAVE_ENABLE_DEVELOPMENT_FEATURES_PROJECT_IDS='["internal"]'
 
 HEXCLAVE_FEATUREBASE_JWT_SECRET=secret-value
diff --git a/apps/dashboard/next.config.mjs b/apps/dashboard/next.config.mjs
index 877eeb8d4..b70ff09a4 100644
--- a/apps/dashboard/next.config.mjs
+++ b/apps/dashboard/next.config.mjs
@@ -131,7 +131,7 @@ const nextConfig = {
             key: "X-Content-Type-Options",
             value: "nosniff",
           },
-          ...process.env.NEXT_PUBLIC_STACK_IS_PREVIEW === "true" ? [] : [{
+          ...resolveHexclaveStackEnvVar("NEXT_PUBLIC_HEXCLAVE_IS_PREVIEW", "NEXT_PUBLIC_STACK_IS_PREVIEW") === "true" ? [] : [{
             key: "X-Frame-Options",
             value: "SAMEORIGIN",
           }],
diff --git a/apps/dashboard/src/lib/remote-development-environment/manager.ts b/apps/dashboard/src/lib/remote-development-environment/manager.ts
index 26d4cc2ec..001dcbbc1 100644
--- a/apps/dashboard/src/lib/remote-development-environment/manager.ts
+++ b/apps/dashboard/src/lib/remote-development-environment/manager.ts
@@ -219,6 +219,21 @@ function createInternalApp(apiBaseUrl: string, anonymousRefreshToken?: string) {
 
 function envVarsForProject(project: RemoteDevelopmentEnvironmentProject): Record<string, string> {
   return {
+    // Canonical Hexclave names (preferred by SDKs/examples post-rebrand)...
+    HEXCLAVE_PROJECT_ID: project.projectId,
+    NEXT_PUBLIC_HEXCLAVE_PROJECT_ID: project.projectId,
+    VITE_HEXCLAVE_PROJECT_ID: project.projectId,
+    EXPO_PUBLIC_HEXCLAVE_PROJECT_ID: project.projectId,
+    HEXCLAVE_PUBLISHABLE_CLIENT_KEY: project.publishableClientKey,
+    NEXT_PUBLIC_HEXCLAVE_PUBLISHABLE_CLIENT_KEY: project.publishableClientKey,
+    VITE_HEXCLAVE_PUBLISHABLE_CLIENT_KEY: project.publishableClientKey,
+    EXPO_PUBLIC_HEXCLAVE_PUBLISHABLE_CLIENT_KEY: project.publishableClientKey,
+    HEXCLAVE_SECRET_SERVER_KEY: project.secretServerKey,
+    HEXCLAVE_API_URL: project.apiBaseUrl,
+    NEXT_PUBLIC_HEXCLAVE_API_URL: project.apiBaseUrl,
+    VITE_HEXCLAVE_API_URL: project.apiBaseUrl,
+    EXPO_PUBLIC_HEXCLAVE_API_URL: project.apiBaseUrl,
+    // ...plus the legacy Stack names so existing/copied setups keep working.
     STACK_PROJECT_ID: project.projectId,
     NEXT_PUBLIC_STACK_PROJECT_ID: project.projectId,
     VITE_STACK_PROJECT_ID: project.projectId,
diff --git a/examples/convex/convex/auth.config.ts b/examples/convex/convex/auth.config.ts
index 513788a2a..2d43cca44 100644
--- a/examples/convex/convex/auth.config.ts
+++ b/examples/convex/convex/auth.config.ts
@@ -1,5 +1,9 @@
 import { getConvexProvidersConfig } from "@hexclave/next/convex-auth.config";
 
+function throwErr(message: string): never {
+  throw new Error(message);
+}
+
 function resolveRenamedEnvVar(hexclaveName: string, stackName: string, hexclaveValue: string | undefined, stackValue: string | undefined): string | undefined {
   if (hexclaveValue && stackValue && hexclaveValue !== stackValue) {
     throw new Error(`Environment variables ${hexclaveName} and ${stackName} are both set to different values. Remove one of them or set them to the same value.`);
@@ -9,7 +13,7 @@ function resolveRenamedEnvVar(hexclaveName: string, stackName: string, hexclaveV
 
 export default {
   providers: getConvexProvidersConfig({
-    projectId: resolveRenamedEnvVar("NEXT_PUBLIC_HEXCLAVE_PROJECT_ID", "NEXT_PUBLIC_STACK_PROJECT_ID", process.env.NEXT_PUBLIC_HEXCLAVE_PROJECT_ID, process.env.NEXT_PUBLIC_STACK_PROJECT_ID)!,
+    projectId: resolveRenamedEnvVar("NEXT_PUBLIC_HEXCLAVE_PROJECT_ID", "NEXT_PUBLIC_STACK_PROJECT_ID", process.env.NEXT_PUBLIC_HEXCLAVE_PROJECT_ID, process.env.NEXT_PUBLIC_STACK_PROJECT_ID) ?? throwErr("NEXT_PUBLIC_HEXCLAVE_PROJECT_ID or NEXT_PUBLIC_STACK_PROJECT_ID must be set"),
     baseUrl: resolveRenamedEnvVar("NEXT_PUBLIC_HEXCLAVE_API_URL", "NEXT_PUBLIC_STACK_API_URL", process.env.NEXT_PUBLIC_HEXCLAVE_API_URL, process.env.NEXT_PUBLIC_STACK_API_URL),
   }),
 }
diff --git a/examples/js-example/hexclave.ts b/examples/js-example/hexclave.ts
index 14ca9197e..ca1050c8e 100644
--- a/examples/js-example/hexclave.ts
+++ b/examples/js-example/hexclave.ts
@@ -3,9 +3,9 @@
 import { StackClientApp } from "@hexclave/js";
 
 export const hexclaveClientApp = new StackClientApp({
-  baseUrl: import.meta.env.VITE_HEXCLAVE_API_URL,
-  projectId: import.meta.env.VITE_HEXCLAVE_PROJECT_ID,
-  publishableClientKey: import.meta.env.VITE_HEXCLAVE_PUBLISHABLE_CLIENT_KEY,
+  baseUrl: import.meta.env.VITE_HEXCLAVE_API_URL || import.meta.env.VITE_STACK_API_URL,
+  projectId: import.meta.env.VITE_HEXCLAVE_PROJECT_ID || import.meta.env.VITE_STACK_PROJECT_ID,
+  publishableClientKey: import.meta.env.VITE_HEXCLAVE_PUBLISHABLE_CLIENT_KEY || import.meta.env.VITE_STACK_PUBLISHABLE_CLIENT_KEY,
   tokenStore: "cookie",
   urls: {
     oauthCallback: window.location.origin + "/oauth",
diff --git a/examples/lovable-react-18-example/src/hexclave/client.ts b/examples/lovable-react-18-example/src/hexclave/client.ts
index 2f47e522a..49ad4b002 100644
--- a/examples/lovable-react-18-example/src/hexclave/client.ts
+++ b/examples/lovable-react-18-example/src/hexclave/client.ts
@@ -3,9 +3,9 @@ import { useNavigate } from "react-router-dom";
 
 export const hexclaveClientApp = new StackClientApp({ 
   tokenStore: "cookie",
-  baseUrl: import.meta.env.VITE_HEXCLAVE_API_URL,
-  projectId: import.meta.env.VITE_HEXCLAVE_PROJECT_ID, 
-  publishableClientKey: import.meta.env.VITE_HEXCLAVE_PUBLISHABLE_CLIENT_KEY,
+  baseUrl: import.meta.env.VITE_HEXCLAVE_API_URL || import.meta.env.VITE_STACK_API_URL,
+  projectId: import.meta.env.VITE_HEXCLAVE_PROJECT_ID || import.meta.env.VITE_STACK_PROJECT_ID,
+  publishableClientKey: import.meta.env.VITE_HEXCLAVE_PUBLISHABLE_CLIENT_KEY || import.meta.env.VITE_STACK_PUBLISHABLE_CLIENT_KEY,
   redirectMethod: {
     useNavigate,
   }, 
diff --git a/examples/react-example/src/hexclave.ts b/examples/react-example/src/hexclave.ts
index 91608be3e..2d3865621 100644
--- a/examples/react-example/src/hexclave.ts
+++ b/examples/react-example/src/hexclave.ts
@@ -4,9 +4,9 @@ import { StackClientApp } from "@hexclave/react";
 import { useNavigate } from "react-router-dom";
 
 export const hexclaveClientApp = new StackClientApp({
-  projectId: import.meta.env.VITE_HEXCLAVE_PROJECT_ID,
-  publishableClientKey: import.meta.env.VITE_HEXCLAVE_PUBLISHABLE_CLIENT_KEY,
-  baseUrl: import.meta.env.VITE_HEXCLAVE_API_URL,
+  projectId: import.meta.env.VITE_HEXCLAVE_PROJECT_ID || import.meta.env.VITE_STACK_PROJECT_ID,
+  publishableClientKey: import.meta.env.VITE_HEXCLAVE_PUBLISHABLE_CLIENT_KEY || import.meta.env.VITE_STACK_PUBLISHABLE_CLIENT_KEY,
+  baseUrl: import.meta.env.VITE_HEXCLAVE_API_URL || import.meta.env.VITE_STACK_API_URL,
   tokenStore: "cookie",
   redirectMethod: {
     useNavigate,
diff --git a/examples/tanstack-start-demo/src/hexclave.ts b/examples/tanstack-start-demo/src/hexclave.ts
index 09cf4fe90..7408316fc 100644
--- a/examples/tanstack-start-demo/src/hexclave.ts
+++ b/examples/tanstack-start-demo/src/hexclave.ts
@@ -9,7 +9,7 @@ function replaceHexclavePortPrefix(value: string): string {
 }
 
 function getStackApiUrl(): string {
-  const configured = import.meta.env.VITE_HEXCLAVE_API_URL as string | undefined;
+  const configured = (import.meta.env.VITE_HEXCLAVE_API_URL || import.meta.env.VITE_STACK_API_URL) as string | undefined;
   return configured ? replaceHexclavePortPrefix(configured) : `http://localhost:${getPortPrefix()}02`;
 }
 
diff --git a/packages/cli/src/lib/auth.ts b/packages/cli/src/lib/auth.ts
index 0ff465ca3..3ff3b387c 100644
--- a/packages/cli/src/lib/auth.ts
+++ b/packages/cli/src/lib/auth.ts
@@ -31,13 +31,13 @@ export type ProjectAuth = (ProjectAuthWithRefreshToken | ProjectAuthWithSecretSe
 };
 
 function resolveApiUrl(): string {
-  return process.env.STACK_API_URL
+  return resolveHexclaveStackEnvVar("HEXCLAVE_API_URL", "STACK_API_URL")
     ?? readConfigValue("STACK_API_URL")
     ?? DEFAULT_API_URL;
 }
 
 function resolveDashboardUrl(): string {
-  return process.env.STACK_DASHBOARD_URL
+  return resolveHexclaveStackEnvVar("HEXCLAVE_DASHBOARD_URL", "STACK_DASHBOARD_URL")
     ?? readConfigValue("STACK_DASHBOARD_URL")
     ?? DEFAULT_DASHBOARD_URL;
 }
diff --git a/packages/shared/src/utils/env.test.tsx b/packages/shared/src/utils/env.test.tsx
index 943e146ef..9ec7f2852 100644
--- a/packages/shared/src/utils/env.test.tsx
+++ b/packages/shared/src/utils/env.test.tsx
@@ -40,4 +40,19 @@ describe("Hexclave/Stack env var dual-read", () => {
   it("returns undefined when both names are empty", () => {
     expect(resolveHexclaveStackEnvVarValue("HEXCLAVE_FOO", "STACK_FOO", "", "")).toBeUndefined();
   });
+
+  it("falls back to the legacy Stack name when a canonical Hexclave name is looked up", () => {
+    vi.stubEnv("NEXT_PUBLIC_STACK_API_URL", "https://stack.example.test");
+
+    // Caller passes the canonical HEXCLAVE_ name but only the legacy value is set.
+    expect(getEnvVariable("NEXT_PUBLIC_HEXCLAVE_API_URL")).toBe("https://stack.example.test");
+    expect(getProcessEnv("NEXT_PUBLIC_HEXCLAVE_API_URL")).toBe("https://stack.example.test");
+  });
+
+  it("throws on a conflict when a canonical Hexclave name is looked up", () => {
+    vi.stubEnv("NEXT_PUBLIC_HEXCLAVE_API_URL", "https://hexclave.example.test");
+    vi.stubEnv("NEXT_PUBLIC_STACK_API_URL", "https://stack.example.test");
+
+    expect(() => getEnvVariable("NEXT_PUBLIC_HEXCLAVE_API_URL")).toThrow(/NEXT_PUBLIC_HEXCLAVE_API_URL.*NEXT_PUBLIC_STACK_API_URL.*different values/);
+  });
 });
diff --git a/packages/shared/src/utils/env.tsx b/packages/shared/src/utils/env.tsx
index 757849413..b95b58ab7 100644
--- a/packages/shared/src/utils/env.tsx
+++ b/packages/shared/src/utils/env.tsx
@@ -10,20 +10,6 @@ const ENV_VAR_RENAME: Record<string, string[] | undefined> = {
   NEXT_PUBLIC_STACK_API_URL: ['STACK_BASE_URL', 'NEXT_PUBLIC_STACK_URL'],
 };
 
-/**
- * Hexclave rebrand: compute the `HEXCLAVE_*`-prefixed equivalent of a `STACK_*`
- * env var name by replacing the first `STACK_` occurrence with `HEXCLAVE_`.
- * Covers `STACK_FOO`, `NEXT_PUBLIC_STACK_FOO`, `NEXT_PUBLIC_BROWSER_STACK_FOO`,
- * `NEXT_PUBLIC_SERVER_STACK_FOO`, `VITE_STACK_FOO`. Returns `undefined` when the
- * name has no `STACK_` segment (caller should behave exactly as before).
- */
-function getHexclaveEnvVarName(name: string): string | undefined {
-  if (!name.includes("STACK_")) {
-    return undefined;
-  }
-  return name.replace("STACK_", "HEXCLAVE_");
-}
-
 export function resolveHexclaveStackEnvVarValue(hexclaveName: string, stackName: string, hexclaveValue: string | undefined, stackValue: string | undefined): string | undefined {
   if (hexclaveValue && stackValue && hexclaveValue !== stackValue) {
     throw new Error(`Environment variables ${hexclaveName} and ${stackName} are both set to different values. Remove one of them or set them to the same value.`);
@@ -31,12 +17,26 @@ export function resolveHexclaveStackEnvVarValue(hexclaveName: string, stackName:
   return hexclaveValue || stackValue || undefined;
 }
 
+/**
+ * Hexclave rebrand: resolve an env var by reading both the `HEXCLAVE_*` and
+ * `STACK_*` spellings, preferring the canonical Hexclave value and falling back
+ * to the legacy Stack value (empty counts as unset). Works in BOTH directions —
+ * whether the caller passes the legacy `STACK_FOO` name or the canonical
+ * `HEXCLAVE_FOO` name, the other spelling is still honored. Covers `STACK_FOO`,
+ * `NEXT_PUBLIC_STACK_FOO`, `NEXT_PUBLIC_BROWSER_STACK_FOO`,
+ * `NEXT_PUBLIC_SERVER_STACK_FOO`, `VITE_STACK_FOO` and their HEXCLAVE_ twins.
+ * Names with neither segment behave exactly as before.
+ */
 function getEnvVarWithHexclaveFallback(name: string): string | undefined {
-  const hexclaveName = getHexclaveEnvVarName(name);
-  if (hexclaveName == null) {
-    return process.env[name];
+  if (name.includes("STACK_")) {
+    const hexclaveName = name.replace("STACK_", "HEXCLAVE_");
+    return resolveHexclaveStackEnvVarValue(hexclaveName, name, process.env[hexclaveName], process.env[name]);
   }
-  return resolveHexclaveStackEnvVarValue(hexclaveName, name, process.env[hexclaveName], process.env[name]);
+  if (name.includes("HEXCLAVE_")) {
+    const stackName = name.replace("HEXCLAVE_", "STACK_");
+    return resolveHexclaveStackEnvVarValue(name, stackName, process.env[name], process.env[stackName]);
+  }
+  return process.env[name];
 }
 
 /**