Introducing Vovk.ts — A Back-End Framework Native to Next.js

#webdev #typescript #nextjs #api

After nearly three years of development, I'm releasing Vovk.ts — a back-end meta-framework built natively on top of Next.js App Router. It turns Route Handlers into a structured API layer with controllers, services, and procedures, and automatically generates type-safe RPC clients, OpenAPI specs, and AI tool definitions from your code.

If you've ever wanted the structured back-end experience of NestJS but without leaving the Next.js deployment model, this is what I've been building.

The idea in 30 seconds

Define a controller with validation in-place:

@prefix("users")
export default class UserController {
  @get('{id}')
  static getUser = procedure({
    params: z.object({ id: z.string().uuid() }),
    output: z.object({ id: z.string(), name: z.string() }),
  }).handle(async (req, { id }) => {
    return UserService.getUser(id);
  });
}

The CLI generates a type-safe client that mirrors the controller:

import { UserRPC } from 'vovk-client';

const user = await UserRPC.getUser({ params: { id: '123' } });

The same procedure runs locally for SSR — no HTTP round-trip:

await UserController.getUser.fn({ params: { id: '123' } });

And it's derivable as an AI tool in one call:

const { tools } = deriveTools({ modules: { UserRPC, TaskController } });
// [{ name, description, parameters, execute }, ...]

That's one endpoint definition generating a typed client, an OpenAPI spec, a local execution path, and an LLM-callable tool.

What it gives you

In-place validation with Zod, Valibot, or ArkType — no separate contracts or DTOs
Auto-generated TypeScript clients with jump-to-definition and JSDoc hover
OpenAPI 3.1 generation with Scalar-compatible docs
Per-segment serverless compilation — each route.ts is its own function with independent runtime config
Local procedure execution via .fn() for SSR, PPR, and background jobs
JSON Lines streaming with async function* generators
Third-party API mixins — import external OpenAPI specs and get the same typed client interface
AI tool derivation and MCP server support out of the box
Multi-language client generation (experimental) for Python and Rust
Multitenancy with built-in subdomain routing

What makes it different

If you've used tRPC, ts-rest, NestJS, oRPC, Hono, or ElysiaJS, many of the ideas here will feel familiar. Each of those tools does something genuinely well, and the patterns they've established informed many of the design decisions in Vovk.ts.

Where Vovk.ts carves its own path is in combining these ideas natively within Next.js App Router: the Controller–Service architecture from NestJS, the type-safe clients from tRPC, the REST compliance and OpenAPI generation from ts-rest. On top of that, it adds things I couldn't find elsewhere: local procedure execution via .fn() and built-in AI tool derivation for LLM agents and MCP servers.

It's not the right tool for every situation — if you're not on Next.js, or if you prefer a contract-first workflow, other options will serve you better. But if you're building a structured API layer on top of the App Router and want all of the above from a single source of truth, I think you'll enjoy it.