diff --git a/app/api/assistant/[assistant_id]/route.ts b/app/api/assistant/[assistant_id]/route.ts
index dd1ed51..45458f9 100644
--- a/app/api/assistant/[assistant_id]/route.ts
+++ b/app/api/assistant/[assistant_id]/route.ts
@@ -23,7 +23,7 @@ export async function GET(
     const { assistant_id } = await params;
 
     // Get backend URL from environment variable
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
     // Forward the request to the actual backend
     const response = await fetch(`${backendUrl}/api/v1/assistant/${assistant_id}`, {
diff --git a/app/api/collections/[collection_id]/route.ts b/app/api/collections/[collection_id]/route.ts
index 2f42cf8..76f80e9 100644
--- a/app/api/collections/[collection_id]/route.ts
+++ b/app/api/collections/[collection_id]/route.ts
@@ -1,6 +1,6 @@
 import { NextResponse } from 'next/server';
 
-const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
 // GET /api/collections/[collection_id] - Get a specific collection
 export async function GET(
diff --git a/app/api/collections/jobs/[job_id]/route.ts b/app/api/collections/jobs/[job_id]/route.ts
index f5fc414..0f8962f 100644
--- a/app/api/collections/jobs/[job_id]/route.ts
+++ b/app/api/collections/jobs/[job_id]/route.ts
@@ -1,6 +1,6 @@
 import { NextResponse } from 'next/server';
 
-const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
 // GET /api/collections/jobs/[job_id] - Get collection job status
 export async function GET(
diff --git a/app/api/collections/route.ts b/app/api/collections/route.ts
index edade40..0b57c27 100644
--- a/app/api/collections/route.ts
+++ b/app/api/collections/route.ts
@@ -2,7 +2,7 @@ import { NextRequest, NextResponse } from 'next/server';
 
 
 export async function GET(request: Request) {
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   if (!apiKey) {
@@ -52,7 +52,7 @@ export async function POST(request: NextRequest) {
     const body = await request.json();
 
     // Get backend URL from environment variable
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
     // Forward the request to the actual backend
     const response = await fetch(`${backendUrl}/api/v1/collections/`, {
diff --git a/app/api/configs/[config_id]/route.ts b/app/api/configs/[config_id]/route.ts
index efb8f18..c6a00e2 100644
--- a/app/api/configs/[config_id]/route.ts
+++ b/app/api/configs/[config_id]/route.ts
@@ -5,7 +5,7 @@ export async function GET(
   { params }: { params: Promise<{ config_id: string }> }
 ) {
   const { config_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
@@ -30,7 +30,7 @@ export async function PATCH(
   { params }: { params: Promise<{ config_id: string }> }
 ) {
   const { config_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
@@ -60,7 +60,7 @@ export async function DELETE(
   { params }: { params: Promise<{ config_id: string }> }
 ) {
   const { config_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
diff --git a/app/api/configs/[config_id]/versions/[version_number]/route.ts b/app/api/configs/[config_id]/versions/[version_number]/route.ts
index a3b309c..175053e 100644
--- a/app/api/configs/[config_id]/versions/[version_number]/route.ts
+++ b/app/api/configs/[config_id]/versions/[version_number]/route.ts
@@ -5,7 +5,7 @@ export async function GET(
   { params }: { params: Promise<{ config_id: string; version_number: string }> }
 ) {
   const { config_id, version_number } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
@@ -33,7 +33,7 @@ export async function DELETE(
   { params }: { params: Promise<{ config_id: string; version_number: string }> }
 ) {
   const { config_id, version_number } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
diff --git a/app/api/configs/[config_id]/versions/route.ts b/app/api/configs/[config_id]/versions/route.ts
index 85d7f96..12768fe 100644
--- a/app/api/configs/[config_id]/versions/route.ts
+++ b/app/api/configs/[config_id]/versions/route.ts
@@ -5,7 +5,7 @@ export async function GET(
   { params }: { params: Promise<{ config_id: string }> }
 ) {
   const { config_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
@@ -30,7 +30,7 @@ export async function POST(
   { params }: { params: Promise<{ config_id: string }> }
 ) {
   const { config_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
diff --git a/app/api/configs/route.ts b/app/api/configs/route.ts
index ea286a9..4c0d510 100644
--- a/app/api/configs/route.ts
+++ b/app/api/configs/route.ts
@@ -1,7 +1,7 @@
 import { NextResponse, NextRequest } from 'next/server';
 
 export async function GET(request: Request) {
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
@@ -36,7 +36,7 @@ export async function POST(request: NextRequest) {
       )
     }
     const body=await request.json();
-    const backendUrl=process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl=process.env.BACKEND_URL || 'http://localhost:8000';
 
     const response=await fetch(`${backendUrl}/api/v1/configs/`, {
       method:'POST',
diff --git a/app/api/document/[document_id]/route.ts b/app/api/document/[document_id]/route.ts
index 125812b..f244967 100644
--- a/app/api/document/[document_id]/route.ts
+++ b/app/api/document/[document_id]/route.ts
@@ -6,7 +6,7 @@ export async function GET(request: Request,
 ) {
 
   const { document_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   if (!apiKey) {
@@ -44,7 +44,7 @@ export async function DELETE(request: Request,
     { params }: { params: Promise<{ document_id: string }> }
 ) {
   const { document_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   if (!apiKey) {
diff --git a/app/api/document/route.ts b/app/api/document/route.ts
index 89aa062..d63edc6 100644
--- a/app/api/document/route.ts
+++ b/app/api/document/route.ts
@@ -2,7 +2,7 @@ import { NextRequest, NextResponse } from 'next/server';
 
 
 export async function GET(request: Request) {
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   if (!apiKey) {
@@ -52,7 +52,7 @@ export async function POST(request: NextRequest) {
     const formData = await request.formData();
 
     // Get backend URL from environment variable
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
     // Forward the request to the actual backend
     const response = await fetch(`${backendUrl}/api/v1/documents/`, {
diff --git a/app/api/evaluations/[id]/route.ts b/app/api/evaluations/[id]/route.ts
index 655033e..f65043b 100644
--- a/app/api/evaluations/[id]/route.ts
+++ b/app/api/evaluations/[id]/route.ts
@@ -48,7 +48,7 @@ export async function GET(
     }
 
     // Real backend mode
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
     const searchParams = request.nextUrl.searchParams;
     const exportFormat = searchParams.get('export_format') || 'row';
diff --git a/app/api/evaluations/datasets/[dataset_id]/route.ts b/app/api/evaluations/datasets/[dataset_id]/route.ts
index a855063..bf65d09 100644
--- a/app/api/evaluations/datasets/[dataset_id]/route.ts
+++ b/app/api/evaluations/datasets/[dataset_id]/route.ts
@@ -16,7 +16,7 @@ export async function GET(
     }
 
     const { dataset_id } = await params;
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
     const searchParams = request.nextUrl.searchParams.toString();
     const queryString = searchParams ? `?${searchParams}` : '';
 
@@ -78,7 +78,7 @@ export async function DELETE(
     const { dataset_id } = await params;
 
     // Get backend URL from environment variable
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
     // Forward the request to the actual backend
     const response = await fetch(`${backendUrl}/api/v1/evaluations/datasets/${dataset_id}`, {
diff --git a/app/api/evaluations/datasets/route.ts b/app/api/evaluations/datasets/route.ts
index 0952446..0a8a3a6 100644
--- a/app/api/evaluations/datasets/route.ts
+++ b/app/api/evaluations/datasets/route.ts
@@ -18,7 +18,7 @@ export async function GET(request: NextRequest) {
     }
 
     // Get backend URL from environment variable
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
     // Forward the request to the actual backend
     const response = await fetch(`${backendUrl}/api/v1/evaluations/datasets`, {
@@ -68,7 +68,7 @@ export async function POST(request: NextRequest) {
     const formData = await request.formData();
 
     // Get backend URL from environment variable
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
     // Forward the request to the actual backend
     const response = await fetch(`${backendUrl}/api/v1/evaluations/datasets`, {
diff --git a/app/api/evaluations/route.ts b/app/api/evaluations/route.ts
index 2742264..2ca8bb7 100644
--- a/app/api/evaluations/route.ts
+++ b/app/api/evaluations/route.ts
@@ -11,7 +11,7 @@ export async function GET(request: NextRequest) {
       return NextResponse.json({ error: 'Missing X-API-KEY' }, { status: 401 });
     }
 
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
     const response = await fetch(`${backendUrl}/api/v1/evaluations`, {
       method: 'GET',
@@ -44,7 +44,7 @@ export async function POST(request: NextRequest) {
     }
 
     const body = await request.json();
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
     const response = await fetch(`${backendUrl}/api/v1/evaluations`, {
       method: 'POST',
diff --git a/app/api/evaluations/stt/datasets/[dataset_id]/route.ts b/app/api/evaluations/stt/datasets/[dataset_id]/route.ts
index 81bc62c..6d53bf8 100644
--- a/app/api/evaluations/stt/datasets/[dataset_id]/route.ts
+++ b/app/api/evaluations/stt/datasets/[dataset_id]/route.ts
@@ -5,7 +5,7 @@ export async function GET(
   { params }: { params: Promise<{ dataset_id: string }> }
 ) {
   const { dataset_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   if (!apiKey) {
@@ -47,7 +47,7 @@ export async function DELETE(
   { params }: { params: Promise<{ dataset_id: string }> }
 ) {
   const { dataset_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   if (!apiKey) {
diff --git a/app/api/evaluations/stt/datasets/route.ts b/app/api/evaluations/stt/datasets/route.ts
index a725ccd..abc30c5 100644
--- a/app/api/evaluations/stt/datasets/route.ts
+++ b/app/api/evaluations/stt/datasets/route.ts
@@ -4,7 +4,7 @@ import { NextResponse, NextRequest } from 'next/server';
 
 export async function GET(request: 
   Request) {
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
@@ -39,7 +39,7 @@ export async function POST(request: NextRequest) {
       )
     }
     const body=await request.json();
-    const backendUrl=process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl=process.env.BACKEND_URL || 'http://localhost:8000';
 
     const response=await fetch(`${backendUrl}/api/v1/evaluations/stt/datasets`, {
       method:'POST',
diff --git a/app/api/evaluations/stt/files/route.ts b/app/api/evaluations/stt/files/route.ts
index 1228134..ab76667 100644
--- a/app/api/evaluations/stt/files/route.ts
+++ b/app/api/evaluations/stt/files/route.ts
@@ -17,7 +17,7 @@ export async function POST(request: NextRequest) {
     const formData = await request.formData();
 
     // Get backend URL from environment variable
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
     // Forward the request to the actual backend
     const response = await fetch(`${backendUrl}/api/v1/evaluations/stt/files`, {
diff --git a/app/api/evaluations/stt/results/[result_id]/route.ts b/app/api/evaluations/stt/results/[result_id]/route.ts
index 829e4d4..16d69d6 100644
--- a/app/api/evaluations/stt/results/[result_id]/route.ts
+++ b/app/api/evaluations/stt/results/[result_id]/route.ts
@@ -5,7 +5,7 @@ export async function GET(
   { params }: { params: Promise<{ result_id: string }> }
 ) {
   const { result_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
@@ -31,7 +31,7 @@ export async function PATCH(
   { params }: { params: Promise<{ result_id: string }> }
 ) {
   const { result_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   if (!apiKey) {
diff --git a/app/api/evaluations/stt/runs/[run_id]/route.ts b/app/api/evaluations/stt/runs/[run_id]/route.ts
index 91cb672..49bac61 100644
--- a/app/api/evaluations/stt/runs/[run_id]/route.ts
+++ b/app/api/evaluations/stt/runs/[run_id]/route.ts
@@ -5,7 +5,7 @@ export async function GET(
   { params }: { params: Promise<{ run_id: string }> }
 ) {
   const { run_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   // Extract query parameters from the request URL
diff --git a/app/api/evaluations/stt/runs/route.ts b/app/api/evaluations/stt/runs/route.ts
index fb81867..e37b629 100644
--- a/app/api/evaluations/stt/runs/route.ts
+++ b/app/api/evaluations/stt/runs/route.ts
@@ -3,7 +3,7 @@ import { NextResponse, NextRequest } from 'next/server';
 
 
 export async function GET(request: Request) {
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
@@ -38,7 +38,7 @@ export async function POST(request: NextRequest) {
       )
     }
     const body=await request.json();
-    const backendUrl=process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl=process.env.BACKEND_URL || 'http://localhost:8000';
 
     const response=await fetch(`${backendUrl}/api/v1/evaluations/stt/runs`, {
       method:'POST',
diff --git a/app/api/evaluations/stt/samples/[sample_id]/route.ts b/app/api/evaluations/stt/samples/[sample_id]/route.ts
index 79b6c14..a9794d3 100644
--- a/app/api/evaluations/stt/samples/[sample_id]/route.ts
+++ b/app/api/evaluations/stt/samples/[sample_id]/route.ts
@@ -5,7 +5,7 @@ export async function PATCH(
   { params }: { params: Promise<{ sample_id: string }> }
 ) {
   const { sample_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   if (!apiKey) {
diff --git a/app/api/evaluations/tts/datasets/[dataset_id]/route.ts b/app/api/evaluations/tts/datasets/[dataset_id]/route.ts
index e7a3080..1ce25c7 100644
--- a/app/api/evaluations/tts/datasets/[dataset_id]/route.ts
+++ b/app/api/evaluations/tts/datasets/[dataset_id]/route.ts
@@ -5,7 +5,7 @@ export async function GET(
   { params }: { params: Promise<{ dataset_id: string }> }
 ) {
   const { dataset_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   if (!apiKey) {
@@ -64,7 +64,7 @@ export async function DELETE(
   { params }: { params: Promise<{ dataset_id: string }> }
 ) {
   const { dataset_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   if (!apiKey) {
diff --git a/app/api/evaluations/tts/datasets/route.ts b/app/api/evaluations/tts/datasets/route.ts
index 4fe9f11..a7a5da3 100644
--- a/app/api/evaluations/tts/datasets/route.ts
+++ b/app/api/evaluations/tts/datasets/route.ts
@@ -1,7 +1,7 @@
 import { NextResponse, NextRequest } from 'next/server';
 
 export async function GET(request: Request) {
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
@@ -31,7 +31,7 @@ export async function POST(request: NextRequest) {
       );
     }
     const body = await request.json();
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
     const response = await fetch(`${backendUrl}/api/v1/evaluations/tts/datasets`, {
       method: 'POST',
diff --git a/app/api/evaluations/tts/results/[result_id]/route.ts b/app/api/evaluations/tts/results/[result_id]/route.ts
index 126d21e..5620737 100644
--- a/app/api/evaluations/tts/results/[result_id]/route.ts
+++ b/app/api/evaluations/tts/results/[result_id]/route.ts
@@ -5,7 +5,7 @@ export async function GET(
   { params }: { params: Promise<{ result_id: string }> }
 ) {
   const { result_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
@@ -30,7 +30,7 @@ export async function PATCH(
   { params }: { params: Promise<{ result_id: string }> }
 ) {
   const { result_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   if (!apiKey) {
diff --git a/app/api/evaluations/tts/runs/[run_id]/route.ts b/app/api/evaluations/tts/runs/[run_id]/route.ts
index e782d4a..5ebbe00 100644
--- a/app/api/evaluations/tts/runs/[run_id]/route.ts
+++ b/app/api/evaluations/tts/runs/[run_id]/route.ts
@@ -5,7 +5,7 @@ export async function GET(
   { params }: { params: Promise<{ run_id: string }> }
 ) {
   const { run_id } = await params;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   const { searchParams } = new URL(request.url);
diff --git a/app/api/evaluations/tts/runs/route.ts b/app/api/evaluations/tts/runs/route.ts
index 9cd9143..37d4719 100644
--- a/app/api/evaluations/tts/runs/route.ts
+++ b/app/api/evaluations/tts/runs/route.ts
@@ -1,7 +1,7 @@
 import { NextResponse, NextRequest } from 'next/server';
 
 export async function GET(request: Request) {
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
@@ -31,7 +31,7 @@ export async function POST(request: NextRequest) {
       );
     }
     const body = await request.json();
-    const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+    const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
 
     const response = await fetch(`${backendUrl}/api/v1/evaluations/tts/runs`, {
       method: 'POST',
diff --git a/app/api/languages/route.ts b/app/api/languages/route.ts
index 00a56f4..50b7805 100644
--- a/app/api/languages/route.ts
+++ b/app/api/languages/route.ts
@@ -1,7 +1,7 @@
 import { NextResponse } from 'next/server';
 
 export async function GET(request: Request) {
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || 'http://localhost:8000';
+  const backendUrl = process.env.BACKEND_URL || 'http://localhost:8000';
   const apiKey = request.headers.get('X-API-KEY');
 
   try {
diff --git a/instructions/CLAUDE.md b/instructions/CLAUDE.md
index 2f93f99..dbe1573 100644
--- a/instructions/CLAUDE.md
+++ b/instructions/CLAUDE.md
@@ -5,6 +5,7 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 ## Project Overview
 
 Kaapi Konsole is a Next.js 16 application by Tech4Dev for LLM development and evaluation. It provides:
+
 - LLM response evaluation against QnA datasets
 - Git-like version control for prompt templates
 - Configuration management with A/B testing
@@ -53,11 +54,13 @@ npm run lint
 ```
 
 **Coming Soon Routes** (placeholders):
+
 - `/model-testing`, `/speech-to-text`, `/text-to-speech`, `/guardrails`, `/redteaming`
 
 ### Component Organization
 
 **Shared Components** (`/app/components/`):
+
 - `Sidebar.tsx` - Main navigation (240px collapsible)
 - `TabNavigation.tsx` - Reusable tab switcher
 - `ConfigModal.tsx` - Modal for viewing evaluation configs
@@ -67,6 +70,7 @@ npm run lint
 - `utils.ts` - Date formatting, color utilities
 
 **Prompt Editor Components** (`/app/components/prompt-editor/`):
+
 - `Header.tsx` - Top nav with branch controls
 - `EditorView.tsx` - WYSIWYG prompt editor
 - `DiffView.tsx` - Side-by-side diff visualization
@@ -78,11 +82,13 @@ npm run lint
 ### State Management Pattern
 
 **No global state library** - uses React `useState` exclusively:
+
 - Component-level state with props drilling
 - LocalStorage for persistence (API keys, sidebar state)
 - No Context API or Redux/Zustand
 
 **LocalStorage Keys:**
+
 - `kaapi_api_keys` - API key storage
 - `sidebar-expanded-menus` - Sidebar expansion state
 
@@ -98,7 +104,7 @@ GET      /api/evaluations/datasets/[dataset_id]
 GET      /api/assistant/[assistant_id] → Fetch assistant config
 ```
 
-**Backend URL**: Configured via `NEXT_PUBLIC_BACKEND_URL` (default: `http://localhost:8000`)
+**Backend URL**: Configured via `BACKEND_URL` (default: `http://localhost:8000`)
 
 **Authentication**: Custom header `X-API-KEY` passed from client
 
@@ -109,6 +115,7 @@ GET      /api/assistant/[assistant_id] → Fetch assistant config
 **Complex Type Hierarchies** in `/app/components/types.ts`:
 
 **Evaluation Types:**
+
 - `EvalJob` - Main evaluation job entity
 - `ScoreObject` - Union type supporting 3 formats:
   - `NewScoreObjectV2` (with `traces[]` array)
@@ -120,6 +127,7 @@ GET      /api/assistant/[assistant_id] → Fetch assistant config
 **Type Guards**: `isNewScoreObjectV2()`, `isLegacyScoreObject()` for runtime type checking
 
 **Prompt Editor Types** in `/app/configurations/prompt-editor/types.ts`:
+
 - `Commit` - Git-like commit with branch/parent relationships
 - `Config` - LLM configuration blob with versioning
 - `Tool` - Vector store tool definition
@@ -131,18 +139,21 @@ GET      /api/assistant/[assistant_id] → Fetch assistant config
 **Current Design**: Vercel-style minimalist black/white theme
 
 **Color Management**:
+
 - All colors defined in `/app/lib/colors.ts` as TypeScript object
 - Synchronized with CSS variables in `globals.css`
 - Dark mode support via `prefers-color-scheme` media query
 - See `COLOR_SCHEME.md` for quick preset options
 
 **Styling Approach**:
+
 1. Tailwind CSS for layout and spacing
 2. Inline styles for colors (referencing `colors` object)
 3. Hover states managed via React event handlers
 4. No custom Tailwind classes or extended theme
 
 **Color Palette**:
+
 ```typescript
 bg: { primary: '#ffffff', secondary: '#fafafa' }
 text: { primary: '#171717', secondary: '#737373' }
@@ -156,6 +167,7 @@ status: { success: '#16a34a', error: '#dc2626', warning: '#f59e0b' }
 ### 1. LLM Evaluation Pipeline
 
 **Workflow**:
+
 1. Upload CSV with `question,answer` columns
 2. Configure experiment (model, instructions, vector stores)
 3. Backend creates evaluation job
@@ -163,10 +175,12 @@ status: { success: '#16a34a', error: '#dc2626', warning: '#f59e0b' }
 5. Results displayed with detailed metrics
 
 **Evaluation Modes**:
+
 - Config-based: Specify model, instructions, tools
 - Assistant-based: Use pre-configured assistant ID
 
 **Metrics Display**:
+
 - Summary scores (avg ± std for numeric, distribution for categorical)
 - Per-item traces with expandable Q&A pairs
 - Color-coded scores with dynamic thresholds
@@ -175,12 +189,14 @@ status: { success: '#16a34a', error: '#dc2626', warning: '#f59e0b' }
 ### 2. Git-like Prompt Version Control
 
 **Core Concepts** (see `/configurations/prompt-editor/page.tsx`):
+
 - **Commits**: Versioned prompt snapshots with author/message/timestamp
 - **Branches**: Parallel development streams (e.g., main, experiment-v2)
 - **Diffs**: Myers algorithm for side-by-side change visualization
 - **Merges**: Branch integration with duplicate commit detection
 
 **Implementation Details**:
+
 - All commits stored in-memory (no backend persistence yet)
 - `createBranch()` preserves uncommitted changes when branching from HEAD
 - `switchBranch()` loads latest commit from target branch
@@ -192,6 +208,7 @@ status: { success: '#16a34a', error: '#dc2626', warning: '#f59e0b' }
 ### 3. Configuration Management & A/B Testing
 
 **Config Structure**:
+
 ```javascript
 {
   id: string,
@@ -207,6 +224,7 @@ status: { success: '#16a34a', error: '#dc2626', warning: '#f59e0b' }
 ```
 
 **Features**:
+
 - Multi-version configs (auto-incremented)
 - "Use Current Prompt" syncs from editor
 - History tab shows all saved configs
@@ -265,16 +283,19 @@ See `CONFIG_AB.md` for complete feature specification.
 ## Backend Integration
 
 **Environment Variables**:
+
 ```bash
-NEXT_PUBLIC_BACKEND_URL=http://localhost:8000  # Backend API base URL
+BACKEND_URL=http://localhost:8000  # Backend API base URL
 ```
 
 **Authentication**:
+
 - API keys stored in localStorage
 - Passed via `X-API-KEY` header
 - No JWT/OAuth implementation
 
 **Dataset Upload**:
+
 - CSV format: `question,expected_answer` columns
 - Duplication factor supported (1-10)
 - Backend handles file processing