Merit-Systems · SlaVKsVolks · May 11, 2026 · Aug 4, 2026
diff --git a/README.md b/README.md
@@ -125,3 +125,8 @@ Fill out `packages/app/control/.env` and `packages/app/server/.env`. Then...
 
 - `pnpm i`
 - `pnpm dev`
+
+## Navigation
+
+- [Back to `REPOS`](../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../README.md)
diff --git a/packages/app/control/README.md b/packages/app/control/README.md
@@ -157,3 +157,16 @@ pnpm start
 ## License
 
 This project is licensed under the MIT License.
+
+## Navigation
+
+- [Back to `packages/app`](../../README.md)
+- [Back to `echo`](../../../README.md)
+- [Back to `REPOS`](../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../README.md)
+## Navigation
+
+- [Back to `packages/app`](../../README.md)
+- [Back to `echo`](../../../README.md)
+- [Back to `REPOS`](../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../README.md)
diff --git a/packages/app/server/README.md b/packages/app/server/README.md
@@ -79,3 +79,16 @@ CMD ["pnpm", "start"]
 ## Error Handling
 
 If the generated Prisma client is not found, the server will throw a descriptive error message asking you to run `pnpm run copy-prisma`.
+
+## Navigation
+
+- [Back to `packages/app`](../../README.md)
+- [Back to `echo`](../../../README.md)
+- [Back to `REPOS`](../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../README.md)
+## Navigation
+
+- [Back to `packages/app`](../../README.md)
+- [Back to `echo`](../../../README.md)
+- [Back to `REPOS`](../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../README.md)
diff --git a/packages/app/server/src/__tests__/README.md b/packages/app/server/src/__tests__/README.md
@@ -200,3 +200,9 @@ The test suite can be extended to cover:
 3. Rate limiting behavior
 4. Concurrent request handling
 5. Performance testing
+## Navigation
+
+- [Back to `packages/app/server/src`](../../../README.md)
+- [Back to `echo`](../../../../README.md)
+- [Back to `REPOS`](../../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../../README.md)
diff --git a/packages/app/server/src/providers/VertexAIProvider.ts b/packages/app/server/src/providers/VertexAIProvider.ts
@@ -19,6 +19,8 @@ import { env } from '../env';
 // Constants
 export const PROXY_PASSTHROUGH_ONLY_MODEL = 'PROXY_PLACEHOLDER_VERTEX_AI';
 const VEO3_MODELS = [
+  'veo-3.1-fast-generate-preview',
+  'veo-3.1-generate-preview',
   'veo-3.0-fast-generate-preview',
   'veo-3.0-generate-preview',
 ];

diff --git a/packages/sdk/aix402/README.md b/packages/sdk/aix402/README.md
@@ -53,3 +53,9 @@ const result = streamText({
   messages: [{ role: 'user', content: 'Hello!' }],
 });
 ```
+## Navigation
+
+- [Back to `packages/sdk`](../../README.md)
+- [Back to `echo`](../../../README.md)
+- [Back to `REPOS`](../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../README.md)
diff --git a/packages/sdk/auth-js-provider/README.md b/packages/sdk/auth-js-provider/README.md
@@ -3,3 +3,10 @@
 An Auth.js Provider for the Echo platform that allows you to use Echo as your authentication provider.
 
 Not yet published on NPM.
+
+## Navigation
+
+- [Back to `packages/sdk`](../../README.md)
+- [Back to `echo`](../../../README.md)
+- [Back to `REPOS`](../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../README.md)
diff --git a/packages/sdk/component-registry/README.md b/packages/sdk/component-registry/README.md
@@ -21,3 +21,10 @@ This is a template for creating a custom registry using Next.js.
 ## Documentation
 
 Visit the [shadcn documentation](https://ui.shadcn.com/docs/registry) to view the full documentation.
+
+## Navigation
+
+- [Back to `packages/sdk`](../../README.md)
+- [Back to `echo`](../../../README.md)
+- [Back to `REPOS`](../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../README.md)
diff --git a/packages/sdk/examples/next-402-chat/README.md b/packages/sdk/examples/next-402-chat/README.md
@@ -229,3 +229,10 @@ Make sure to update your Echo app configuration with your production domain.
 ---
 
 Built with ❤️ using [Echo](https://echo.merit.systems) - The simplest way to build AI applications with built-in billing and user management.
+
+## Navigation
+
+- [Back to `packages/sdk/examples`](../../../README.md)
+- [Back to `echo`](../../../../README.md)
+- [Back to `REPOS`](../../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../../README.md)
diff --git a/packages/sdk/examples/next/README.md b/packages/sdk/examples/next/README.md
@@ -34,3 +34,10 @@ You can check out [the Next.js GitHub repository](https://github.com/vercel/next
 The easiest way to deploy your Next.js app is to use the [Vercel Platform](https://vercel.com/new?utm_medium=default-template&filter=next.js&utm_source=create-next-app&utm_campaign=create-next-app-readme) from the creators of Next.js.
 
 Check out our [Next.js deployment documentation](https://nextjs.org/docs/app/building-your-application/deploying) for more details.
+
+## Navigation
+
+- [Back to `packages/sdk/examples`](../../../README.md)
+- [Back to `echo`](../../../../README.md)
+- [Back to `REPOS`](../../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../../README.md)
diff --git a/packages/sdk/examples/vite/README.md b/packages/sdk/examples/vite/README.md
@@ -25,3 +25,10 @@ The entire app is in `src/App.tsx` - just 70 lines of code demonstrating:
 4. Using `EchoSignIn` and `EchoTokens` components
 
 This shows the complete user journey from sign-up to having a positive balance.
+
+## Navigation
+
+- [Back to `packages/sdk/examples`](../../../README.md)
+- [Back to `echo`](../../../../README.md)
+- [Back to `REPOS`](../../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../../README.md)
diff --git a/packages/sdk/next/README.md b/packages/sdk/next/README.md
@@ -255,3 +255,10 @@ For complete documentation and examples, visit:
 - Next.js 15.0.0 or higher
 - React 18.0.0 or 19.0.0
 - Node.js 18 or higher
+
+## Navigation
+
+- [Back to `packages/sdk`](../../README.md)
+- [Back to `echo`](../../../README.md)
+- [Back to `REPOS`](../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../README.md)
diff --git a/packages/sdk/react/README.md b/packages/sdk/react/README.md
@@ -8,6 +8,13 @@ React SDK for Echo OAuth2 + PKCE authentication and token management.
 pnpm install @merit-systems/echo-react-sdk
 ```
 
+## Navigation
+
+- [Back to `packages/sdk`](../../README.md)
+- [Back to `echo`](../../../README.md)
+- [Back to `REPOS`](../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../README.md)
+
 ## Setup
 
 ```tsx

diff --git a/packages/sdk/ts/README.md b/packages/sdk/ts/README.md
@@ -8,6 +8,13 @@ The official TypeScript SDK for the Echo platform, providing easy access to Echo
 pnpm install @merit-systems/echo-typescript-sdk
 ```
 
+## Navigation
+
+- [Back to `packages/sdk`](../../README.md)
+- [Back to `echo`](../../../README.md)
+- [Back to `REPOS`](../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../README.md)
+
 ## Programmatic Usage
 
 ```typescript

diff --git a/packages/sdk/ts/src/__tests__/README.md b/packages/sdk/ts/src/__tests__/README.md
@@ -227,3 +227,10 @@ The test suite is designed for CI/CD environments:
 - Coverage reporting
 - Parallel test execution support
 - Deterministic test results
+
+## Navigation
+
+- [Back to `packages/sdk/ts`](../../../README.md)
+- [Back to `echo`](../../../../README.md)
+- [Back to `REPOS`](../../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../../README.md)
diff --git a/packages/sdk/ts/src/supported-models/video/vertex-ai.test.ts b/packages/sdk/ts/src/supported-models/video/vertex-ai.test.ts
@@ -0,0 +1,24 @@
+import { describe, expect, it } from 'vitest';
+
+import { VertexAIVideoModels } from './vertex-ai';
+
+describe('VertexAIVideoModels', () => {
+  it('includes Veo 3.1 preview models with pricing metadata', () => {
+    expect(VertexAIVideoModels).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({
+          cost_per_second_with_audio: 0.15,
+          cost_per_second_without_audio: 0.1,
+          model_id: 'veo-3.1-fast-generate-preview',
+          provider: 'VertexAI',
+        }),
+        expect.objectContaining({
+          cost_per_second_with_audio: 0.4,
+          cost_per_second_without_audio: 0.2,
+          model_id: 'veo-3.1-generate-preview',
+          provider: 'VertexAI',
+        }),
+      ]),
+    );
+  });
+});
diff --git a/packages/sdk/ts/src/supported-models/video/vertex-ai.ts b/packages/sdk/ts/src/supported-models/video/vertex-ai.ts
@@ -1,26 +1,40 @@
 import type { SupportedVideoModel } from '../types';
 
 export type VertexAIVideoModel =
+  | 'veo-3.1-fast-generate-preview'
+  | 'veo-3.1-generate-preview'
   | 'veo-3.0-fast-generate-preview'
   | 'veo-3.0-generate-preview';
 /**
  * Vertex AI video models with official pricing information
  * Based on: https://cloud.google.com/vertex-ai/generative-ai/pricing
  *
- * Veo 3: $0.40/second with audio, $0.20/second video only
- * Veo 3 Fast: $0.15/second with audio, $0.10/second video only
+ * Veo 3 / 3.1: $0.40/second with audio, $0.20/second video only
+ * Veo 3 / 3.1 Fast: $0.15/second with audio, $0.10/second video only
  */
 export const VertexAIVideoModels: SupportedVideoModel[] = [
+  {
+    model_id: 'veo-3.1-fast-generate-preview',
+    cost_per_second_with_audio: 0.15,
+    cost_per_second_without_audio: 0.1,
+    provider: 'VertexAI',
+  },
+  {
+    model_id: 'veo-3.1-generate-preview',
+    cost_per_second_with_audio: 0.4,
+    cost_per_second_without_audio: 0.2,
+    provider: 'VertexAI',
+  },
   {
     model_id: 'veo-3.0-fast-generate-preview',
     cost_per_second_with_audio: 0.15,
-    cost_per_second_without_audio: 0.1, // Fixed: was 0.1, now 0.10 for clarity
+    cost_per_second_without_audio: 0.1,
     provider: 'VertexAI',
   },
   {
     model_id: 'veo-3.0-generate-preview',
-    cost_per_second_with_audio: 0.4, // Fixed: was 0.4, now 0.40 for clarity
-    cost_per_second_without_audio: 0.2, // Fixed: was 0.2, now 0.20 for clarity
+    cost_per_second_with_audio: 0.4,
+    cost_per_second_without_audio: 0.2,
     provider: 'VertexAI',
   },
 ];
diff --git a/packages/tests/integration/README.md b/packages/tests/integration/README.md
@@ -80,3 +80,10 @@ Reset only:
 ```bash
 pnpm db:reset
 ```
+
+## Navigation
+
+- [Back to `packages/tests`](../../README.md)
+- [Back to `echo`](../../../README.md)
+- [Back to `REPOS`](../../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../../README.md)
diff --git a/templates/README.md b/templates/README.md
@@ -306,3 +306,9 @@ Some templates (like `nextjs-api-key-template`) may require additional environme
 ---
 
 Built with ❤️ by [Merit Systems](https://merit.systems)
+
+## Navigation
+
+- [Back to `echo`](../README.md)
+- [Back to `REPOS`](../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../README.md)
diff --git a/templates/assistant-ui/README.md b/templates/assistant-ui/README.md
@@ -87,3 +87,10 @@ const runtime = useChatRuntime({
 ## API Route
 
 The API route at `/api/chat` uses the new `streamText` function from AI SDK v5 to handle chat completions.
+
+## Navigation
+
+- [Back to `templates`](../README.md)
+- [Back to `echo`](../../README.md)
+- [Back to `REPOS`](../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../README.md)
diff --git a/templates/authjs/README.md b/templates/authjs/README.md
@@ -46,3 +46,10 @@ You can check out [the Next.js GitHub repository](https://github.com/vercel/next
 The easiest way to deploy your Next.js app is to use the [Vercel Platform](https://vercel.com/new?utm_medium=default-template&filter=next.js&utm_source=create-next-app&utm_campaign=create-next-app-readme) from the creators of Next.js.
 
 Check out our [Next.js deployment documentation](https://nextjs.org/docs/app/building-your-application/deploying) for more details.
+
+## Navigation
+
+- [Back to `templates`](../README.md)
+- [Back to `echo`](../../README.md)
+- [Back to `REPOS`](../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../README.md)
diff --git a/templates/echo-cli/README.md b/templates/echo-cli/README.md
@@ -320,3 +320,10 @@ MIT
 ---
 
 Built with ❤️ by [Merit Systems](https://merit.systems)
+
+## Navigation
+
+- [Back to `templates`](../README.md)
+- [Back to `echo`](../../README.md)
+- [Back to `REPOS`](../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../README.md)
diff --git a/templates/next-chat/README.md b/templates/next-chat/README.md
@@ -243,3 +243,10 @@ Make sure to update your Echo app configuration with your production domain.
 ---
 
 Built with ❤️ using [Echo](https://echo.merit.systems) - The simplest way to build AI applications with built-in billing and user management.
+
+## Navigation
+
+- [Back to `templates`](../README.md)
+- [Back to `echo`](../../README.md)
+- [Back to `REPOS`](../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../README.md)
diff --git a/templates/next-image/README.md b/templates/next-image/README.md
@@ -44,3 +44,10 @@ You can check out [the Next.js GitHub repository](https://github.com/vercel/next
 The easiest way to deploy your Next.js app is to use the [Vercel Platform](https://vercel.com/new?utm_medium=default-template&filter=next.js&utm_source=create-next-app&utm_campaign=create-next-app-readme) from the creators of Next.js.
 
 Check out our [Next.js deployment documentation](https://nextjs.org/docs/app/building-your-application/deploying) for more details.
+
+## Navigation
+
+- [Back to `templates`](../README.md)
+- [Back to `echo`](../../README.md)
+- [Back to `REPOS`](../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../README.md)
diff --git a/templates/next-video-template/README.md b/templates/next-video-template/README.md
@@ -44,3 +44,10 @@ You can check out [the Next.js GitHub repository](https://github.com/vercel/next
 The easiest way to deploy your Next.js app is to use the [Vercel Platform](https://vercel.com/new?utm_medium=default-template&filter=next.js&utm_source=create-next-app&utm_campaign=create-next-app-readme) from the creators of Next.js.
 
 Check out our [Next.js deployment documentation](https://nextjs.org/docs/app/building-your-application/deploying) for more details.
+
+## Navigation
+
+- [Back to `templates`](../README.md)
+- [Back to `echo`](../../README.md)
+- [Back to `REPOS`](../../../README.md)
+- [Back to `AI_REVENUE_SPRINT_100_24H`](../../../../README.md)
diff --git a/templates/next-video-template/src/app/api/generate-video/validation.ts b/templates/next-video-template/src/app/api/generate-video/validation.ts
@@ -35,6 +35,8 @@ export function validateGenerateVideoRequest(body: unknown): ValidationResult {
   }
 
   const validModels: VideoModelOption[] = [
+    'veo-3.1-fast-generate-preview',
+    'veo-3.1-generate-preview',
     'veo-3.0-fast-generate-preview',
     'veo-3.0-generate-preview',
   ];

diff --git a/templates/next-video-template/src/app/api/generate-video/vertex.ts b/templates/next-video-template/src/app/api/generate-video/vertex.ts
@@ -4,6 +4,7 @@
 
 import { getEchoToken } from '@/echo';
 import { ERROR_MESSAGES } from '@/lib/constants';
+import type { VideoModelOption } from '@/lib/types';
 import {
   GenerateVideosOperation,
   GenerateVideosParameters,
@@ -14,7 +15,7 @@ import {
  */
 export async function handleGeminiGenerate(
   prompt: string,
-  model: 'veo-3.0-fast-generate-preview' | 'veo-3.0-generate-preview',
+  model: VideoModelOption,
   durationSeconds: number = 4,
   generateAudio: boolean = false,
   image?: string, // Base64 encoded image or data URL (first frame)

diff --git a/templates/next-video-template/src/components/video-generator.tsx b/templates/next-video-template/src/components/video-generator.tsx
@@ -42,6 +42,8 @@ import { FileInputManager } from './FileInputManager';
 import { VideoHistory } from './video-history';
 
 const models: VideoModelConfig[] = [
+  { id: 'veo-3.1-fast-generate-preview', name: 'Veo 3.1 Fast' },
+  { id: 'veo-3.1-generate-preview', name: 'Veo 3.1' },
   { id: 'veo-3.0-fast-generate-preview', name: 'Veo 3 Fast' },
   { id: 'veo-3.0-generate-preview', name: 'Veo 3' },
 ];
@@ -57,7 +59,7 @@ const models: VideoModelConfig[] = [
  */
 export default function VideoGenerator() {
   const [model, setModel] = useState<VideoModelOption>(
-    'veo-3.0-fast-generate-preview'
+    'veo-3.1-fast-generate-preview'
   );
   const [durationSeconds, setDurationSeconds] = useState<4 | 6 | 8>(4);
   const [generateAudio, setGenerateAudio] = useState<boolean>(false);

diff --git a/templates/next-video-template/src/lib/types.ts b/templates/next-video-template/src/lib/types.ts
@@ -14,6 +14,8 @@ export type ModelOption = 'openai' | 'gemini';
  * Available AI models for video generation
  */
 export type VideoModelOption =
+  | 'veo-3.1-fast-generate-preview'
+  | 'veo-3.1-generate-preview'
   | 'veo-3.0-fast-generate-preview'
   | 'veo-3.0-generate-preview';