diff --git a/.env.example b/.env.example
index aa14c0b..5a93ac2 100644
--- a/.env.example
+++ b/.env.example
@@ -11,6 +11,7 @@ API_KEY=api_key_optional
 # TTS_RETRY_INITIAL_MS=250
 # TTS_RETRY_MAX_MS=2000
 # TTS_RETRY_BACKOFF=2
+# TTS_UPSTREAM_TIMEOUT_MS=285000       # 285 seconds
 
 # (Optional) Enable TTS character rate limiting (default is `false`)
 # TTS_ENABLE_RATE_LIMIT=true
diff --git a/docs-site/docs/reference/environment-variables.md b/docs-site/docs/reference/environment-variables.md
index 74fed09..0c525c8 100644
--- a/docs-site/docs/reference/environment-variables.md
+++ b/docs-site/docs/reference/environment-variables.md
@@ -25,6 +25,7 @@ This is the single reference page for OpenReader environment variables.
 | `TTS_RETRY_INITIAL_MS` | TTS retry | `250` | Tune initial retry delay |
 | `TTS_RETRY_MAX_MS` | TTS retry | `2000` | Tune max retry delay |
 | `TTS_RETRY_BACKOFF` | TTS retry | `2` | Tune exponential backoff factor |
+| `TTS_UPSTREAM_TIMEOUT_MS` | TTS request timeout | `285000` | Set max upstream TTS request duration before fail-fast |
 | `TTS_ENABLE_RATE_LIMIT` | Rate limiting | `false` | Set `true` to enable TTS per-user/IP daily character limits |
 | `TTS_DAILY_LIMIT_ANONYMOUS` | Rate limiting | `50000` | Override anonymous per-user daily character limit |
 | `TTS_DAILY_LIMIT_AUTHENTICATED` | Rate limiting | `500000` | Override authenticated per-user daily character limit |
@@ -113,6 +114,14 @@ Exponential backoff multiplier between retries.
 
 - Default: `2`
 
+### TTS_UPSTREAM_TIMEOUT_MS
+
+Maximum upstream TTS request timeout in milliseconds.
+
+- Default: `285000` (285 seconds)
+- Applies to outbound provider calls from server routes using shared TTS generation
+- Increase for slower providers/models; decrease to fail fast and surface retryable errors sooner
+
 ### TTS_ENABLE_RATE_LIMIT
 
 Controls TTS character rate limiting in the TTS API.
diff --git a/docs-site/versioned_docs/version-v2.0.0/reference/environment-variables.md b/docs-site/versioned_docs/version-v2.0.0/reference/environment-variables.md
index daef2bd..152d693 100644
--- a/docs-site/versioned_docs/version-v2.0.0/reference/environment-variables.md
+++ b/docs-site/versioned_docs/version-v2.0.0/reference/environment-variables.md
@@ -24,6 +24,7 @@ This is the single reference page for OpenReader environment variables.
 | `TTS_RETRY_INITIAL_MS` | TTS retry | `250` | Tune initial retry delay |
 | `TTS_RETRY_MAX_MS` | TTS retry | `2000` | Tune max retry delay |
 | `TTS_RETRY_BACKOFF` | TTS retry | `2` | Tune exponential backoff factor |
+| `TTS_UPSTREAM_TIMEOUT_MS` | TTS request timeout | `285000` | Set max upstream TTS request duration before fail-fast |
 | `TTS_ENABLE_RATE_LIMIT` | Rate limiting | `false` | Set `true` to enable TTS per-user/IP daily character limits |
 | `TTS_DAILY_LIMIT_ANONYMOUS` | Rate limiting | `50000` | Override anonymous per-user daily character limit |
 | `TTS_DAILY_LIMIT_AUTHENTICATED` | Rate limiting | `500000` | Override authenticated per-user daily character limit |
@@ -110,6 +111,14 @@ Exponential backoff multiplier between retries.
 
 - Default: `2`
 
+### TTS_UPSTREAM_TIMEOUT_MS
+
+Maximum upstream TTS request timeout in milliseconds.
+
+- Default: `285000` (285 seconds)
+- Applies to outbound provider calls from server routes using shared TTS generation
+- Increase for slower providers/models; decrease to fail fast and surface retryable errors sooner
+
 ### TTS_ENABLE_RATE_LIMIT
 
 Controls TTS character rate limiting in the TTS API.
diff --git a/docs-site/versioned_docs/version-v2.0.1/reference/environment-variables.md b/docs-site/versioned_docs/version-v2.0.1/reference/environment-variables.md
index daef2bd..152d693 100644
--- a/docs-site/versioned_docs/version-v2.0.1/reference/environment-variables.md
+++ b/docs-site/versioned_docs/version-v2.0.1/reference/environment-variables.md
@@ -24,6 +24,7 @@ This is the single reference page for OpenReader environment variables.
 | `TTS_RETRY_INITIAL_MS` | TTS retry | `250` | Tune initial retry delay |
 | `TTS_RETRY_MAX_MS` | TTS retry | `2000` | Tune max retry delay |
 | `TTS_RETRY_BACKOFF` | TTS retry | `2` | Tune exponential backoff factor |
+| `TTS_UPSTREAM_TIMEOUT_MS` | TTS request timeout | `285000` | Set max upstream TTS request duration before fail-fast |
 | `TTS_ENABLE_RATE_LIMIT` | Rate limiting | `false` | Set `true` to enable TTS per-user/IP daily character limits |
 | `TTS_DAILY_LIMIT_ANONYMOUS` | Rate limiting | `50000` | Override anonymous per-user daily character limit |
 | `TTS_DAILY_LIMIT_AUTHENTICATED` | Rate limiting | `500000` | Override authenticated per-user daily character limit |
@@ -110,6 +111,14 @@ Exponential backoff multiplier between retries.
 
 - Default: `2`
 
+### TTS_UPSTREAM_TIMEOUT_MS
+
+Maximum upstream TTS request timeout in milliseconds.
+
+- Default: `285000` (285 seconds)
+- Applies to outbound provider calls from server routes using shared TTS generation
+- Increase for slower providers/models; decrease to fail fast and surface retryable errors sooner
+
 ### TTS_ENABLE_RATE_LIMIT
 
 Controls TTS character rate limiting in the TTS API.
diff --git a/docs-site/versioned_docs/version-v2.1.0/reference/environment-variables.md b/docs-site/versioned_docs/version-v2.1.0/reference/environment-variables.md
index 74fed09..0c525c8 100644
--- a/docs-site/versioned_docs/version-v2.1.0/reference/environment-variables.md
+++ b/docs-site/versioned_docs/version-v2.1.0/reference/environment-variables.md
@@ -25,6 +25,7 @@ This is the single reference page for OpenReader environment variables.
 | `TTS_RETRY_INITIAL_MS` | TTS retry | `250` | Tune initial retry delay |
 | `TTS_RETRY_MAX_MS` | TTS retry | `2000` | Tune max retry delay |
 | `TTS_RETRY_BACKOFF` | TTS retry | `2` | Tune exponential backoff factor |
+| `TTS_UPSTREAM_TIMEOUT_MS` | TTS request timeout | `285000` | Set max upstream TTS request duration before fail-fast |
 | `TTS_ENABLE_RATE_LIMIT` | Rate limiting | `false` | Set `true` to enable TTS per-user/IP daily character limits |
 | `TTS_DAILY_LIMIT_ANONYMOUS` | Rate limiting | `50000` | Override anonymous per-user daily character limit |
 | `TTS_DAILY_LIMIT_AUTHENTICATED` | Rate limiting | `500000` | Override authenticated per-user daily character limit |
@@ -113,6 +114,14 @@ Exponential backoff multiplier between retries.
 
 - Default: `2`
 
+### TTS_UPSTREAM_TIMEOUT_MS
+
+Maximum upstream TTS request timeout in milliseconds.
+
+- Default: `285000` (285 seconds)
+- Applies to outbound provider calls from server routes using shared TTS generation
+- Increase for slower providers/models; decrease to fail fast and surface retryable errors sooner
+
 ### TTS_ENABLE_RATE_LIMIT
 
 Controls TTS character rate limiting in the TTS API.
diff --git a/docs-site/versioned_docs/version-v2.1.1/reference/environment-variables.md b/docs-site/versioned_docs/version-v2.1.1/reference/environment-variables.md
index 74fed09..0c525c8 100644
--- a/docs-site/versioned_docs/version-v2.1.1/reference/environment-variables.md
+++ b/docs-site/versioned_docs/version-v2.1.1/reference/environment-variables.md
@@ -25,6 +25,7 @@ This is the single reference page for OpenReader environment variables.
 | `TTS_RETRY_INITIAL_MS` | TTS retry | `250` | Tune initial retry delay |
 | `TTS_RETRY_MAX_MS` | TTS retry | `2000` | Tune max retry delay |
 | `TTS_RETRY_BACKOFF` | TTS retry | `2` | Tune exponential backoff factor |
+| `TTS_UPSTREAM_TIMEOUT_MS` | TTS request timeout | `285000` | Set max upstream TTS request duration before fail-fast |
 | `TTS_ENABLE_RATE_LIMIT` | Rate limiting | `false` | Set `true` to enable TTS per-user/IP daily character limits |
 | `TTS_DAILY_LIMIT_ANONYMOUS` | Rate limiting | `50000` | Override anonymous per-user daily character limit |
 | `TTS_DAILY_LIMIT_AUTHENTICATED` | Rate limiting | `500000` | Override authenticated per-user daily character limit |
@@ -113,6 +114,14 @@ Exponential backoff multiplier between retries.
 
 - Default: `2`
 
+### TTS_UPSTREAM_TIMEOUT_MS
+
+Maximum upstream TTS request timeout in milliseconds.
+
+- Default: `285000` (285 seconds)
+- Applies to outbound provider calls from server routes using shared TTS generation
+- Increase for slower providers/models; decrease to fail fast and surface retryable errors sooner
+
 ### TTS_ENABLE_RATE_LIMIT
 
 Controls TTS character rate limiting in the TTS API.
diff --git a/src/lib/server/tts/generate.ts b/src/lib/server/tts/generate.ts
index b23a69c..45bb9ea 100644
--- a/src/lib/server/tts/generate.ts
+++ b/src/lib/server/tts/generate.ts
@@ -204,7 +204,7 @@ async function runProviderRequest(request: ResolvedServerTTSRequest, signal: Abo
     apiKey: request.apiKey,
     baseURL: request.baseUrl,
     maxRetries: 0,
-    timeout: Number(process.env.TTS_UPSTREAM_TIMEOUT_MS ?? 45_000),
+    timeout: Number(process.env.TTS_UPSTREAM_TIMEOUT_MS ?? 285_000),
   });
 
   const createParams: ExtendedSpeechParams = {