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Params Validation

Validate path parameters (e.g. from dynamic routes like [id]) by defining a params schema for the method in your route's schema.ts. BurgerAPI runs validation before the handler; validated params are on ctx.validated.params. Path values are text, so enable coercion if you expect a typed param (e.g. a number id).

See Schema Definition and the full Validation guide for examples.

Types for this feature​

The params schema types ctx.validated.params.

The types you use (from burger-api):

  • defineRoute(schema, handler): infers the handler type from schema; no generic to write
  • BurgerContext<typeof GET>: the same inference, written by hand
  • ctx.validated.params: the validated path parameters

✅ Correct. Validated params are typed from the schema:

api/products/[id]/schema.ts
import { z } from "zod";
export const GET = { params: z.object({ id: z.string().uuid() }) };
api/products/[id]/route.ts
import { defineRoute } from "burger-api";
import { GET as GetSchema } from "./schema";

export const GET = defineRoute(GetSchema, (ctx) => {
    const { id } = ctx.validated.params; // typed: string
    return Response.json({ id });
});

❌ Wrong. A parameter name that is not in the schema:

export const GET = defineRoute(GetSchema, (ctx) => {
    ctx.validated.params.wrong; // ❌ Property 'wrong' does not exist
});

Without a params schema, ctx.params is still always Record<string, string> (empty when the route has no [param] segments), but the values are plain strings: the framework does not check or convert them. For typed parameters, always add the schema. See the TypeScript overview.

Check your code: bun run typecheck.