Support for zod/v4 & zod/v4-mini

[MarkLee425]

Failed to start application: [query.healthCheck.healthCheck] - Input parser expects a Zod validator
It currently does not support zod v4 and mini

[devtempmac]

hmm maybe trpc-openapi can use typeschema to support all typeschema-compatible-schema-validation?

typeschema has toJSONSchema, so I'm guessing it should work without a lot of work

also, trpc's official openapi package (deprecated) seems to recommend https://github.com/mcampa/trpc-to-openapi
(though that repo doesn't have the 'issues' tab)

[necky2]

Same problem. Here is a reproducible example:

Produces an error in a NextJS app with zod 4.0.5, but it works perfectly fine with zod 3.25.76.

// src/app/api/openapi.json/route.ts
import { initTRPC } from "@trpc/server";
import { generateOpenApiDocument } from "trpc-to-openapi";
import { OpenApiMeta } from "trpc-to-openapi";
import { z } from "zod";

const t = initTRPC.meta<OpenApiMeta>().create();

const openApiRouter = t.router({
  sayHello: t.procedure
    .meta({
      openapi: {
        method: "GET",
        path: "/say-hello",
      },
    })
    .input(z.object({ name: z.string() }))
    .output(z.object({ greeting: z.string() }))
    .query(({ input }) => {
      return { greeting: `Hello ${input.name}!` };
    }),
});

export const openApiDocument = generateOpenApiDocument(openApiRouter, {
  title: "tRPC OpenAPI",
  version: "1.0.0",
  baseUrl: "http://localhost:3000",
});

export async function GET() {
  return Response.json(openApiDocument);
}

Error:

Runtime Error
TRPCError: [query.sayHello] - Input parser expects a Zod validator
src/app/api/openapi.json/route.ts (23:55) @ eval
  21 | });
  22 |
> 23 | export const openApiDocument = generateOpenApiDocument(openApiRouter, {
     |                                                       ^
  24 |   title: "tRPC OpenAPI",
  25 |   version: "1.0.0",
  26 |   baseUrl: "http://localhost:3000",

[MarkLee425]

hmm maybe trpc-openapi can use typeschema to support all typeschema-compatible-schema-validation?

typeschema has toJSONSchema, so I'm guessing it should work without a lot of work

also, trpc's official openapi package (deprecated) seems to recommend https://github.com/mcampa/trpc-to-openapi
(though that repo doesn't have the 'issues' tab)

Yes exactly, I cannot find any discussion or issues tab. That's why I raise the issue here instead, hoping any maintainers can find it.