diff --git a/README.md b/README.md
index a35669e..38e73a4 100644
--- a/README.md
+++ b/README.md
@@ -158,6 +158,12 @@ GANTT_API_BEARER_TOKEN=         # Optional server-to-server auth header
 GANTT_API_COOKIE=               # Optional server-to-server cookie header
 ```
 
+`/tasks`, `/projects`, and `/mission` read data server-side from `gantt-board` via:
+1. `GANTT_API_BASE_URL`
+2. `NEXT_PUBLIC_GANTT_API_BASE_URL`
+3. `NEXT_PUBLIC_GANTT_BOARD_URL + /api` (fallback)
+4. default `http://localhost:3000/api` (local-only fallback)
+
 Website URLs are centralized in `lib/config/sites.ts` and can be overridden via the optional variables above.
 
 ## Getting Started
diff --git a/docker-compose.yml b/docker-compose.yml
index 94f733c..6c84553 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -44,7 +44,7 @@ services:
       NEXT_PUBLIC_APP_URL: ${NEXT_PUBLIC_APP_URL:-}
       SUPABASE_SERVICE_ROLE_KEY: ${SUPABASE_SERVICE_ROLE_KEY:-}
       SUPABASE_URL: ${NEXT_PUBLIC_SUPABASE_URL:-}
-      SUPABASE_ANON_KEY: ${SUPABASENEXT_PUBLIC_SUPABASE_ANON_KEY_ANON_KEY:-}
+      SUPABASE_ANON_KEY: ${NEXT_PUBLIC_SUPABASE_ANON_KEY:-}
       GANTT_API_BASE_URL: ${GANTT_API_BASE_URL:-}
       GANTT_API_REVALIDATE_SECONDS: ${GANTT_API_REVALIDATE_SECONDS:-}
       GANTT_API_BEARER_TOKEN: ${GANTT_API_BEARER_TOKEN:-}
diff --git a/lib/data/gantt-api.ts b/lib/data/gantt-api.ts
index 92d72c3..df37ebc 100644
--- a/lib/data/gantt-api.ts
+++ b/lib/data/gantt-api.ts
@@ -1,5 +1,6 @@
 const DEFAULT_GANTT_API_BASE_URL = "http://localhost:3000/api";
 const DEFAULT_REVALIDATE_SECONDS = 15;
+let hasWarnedDefaultBaseUrl = false;
 
 type CacheEntry = {
   expiresAt: number;
@@ -13,11 +14,41 @@ function normalizeBaseUrl(url: string): string {
   return url.replace(/\/+$/, "");
 }
 
+function deriveApiBaseUrlFromGanttBoardUrl(): string | null {
+  const ganttBoardUrl = process.env.NEXT_PUBLIC_GANTT_BOARD_URL;
+  if (!ganttBoardUrl) return null;
+
+  try {
+    const parsed = new URL(ganttBoardUrl);
+    const pathname = parsed.pathname.replace(/\/+$/, "");
+    parsed.pathname = `${pathname}/api`;
+    parsed.search = "";
+    parsed.hash = "";
+    return normalizeBaseUrl(parsed.toString());
+  } catch {
+    return null;
+  }
+}
+
 export function getGanttApiBaseUrl(): string {
+  const derivedFromGanttBoardUrl = deriveApiBaseUrlFromGanttBoardUrl();
   const configured =
     process.env.GANTT_API_BASE_URL ||
     process.env.NEXT_PUBLIC_GANTT_API_BASE_URL ||
+    derivedFromGanttBoardUrl ||
     DEFAULT_GANTT_API_BASE_URL;
+
+  if (
+    configured === DEFAULT_GANTT_API_BASE_URL &&
+    process.env.NODE_ENV === "production" &&
+    !hasWarnedDefaultBaseUrl
+  ) {
+    hasWarnedDefaultBaseUrl = true;
+    console.warn(
+      "[gantt-api] Using default base URL http://localhost:3000/api. Set GANTT_API_BASE_URL or NEXT_PUBLIC_GANTT_API_BASE_URL for deployed environments.",
+    );
+  }
+
   return normalizeBaseUrl(configured);
 }