[BUG] ORPC server returns 400 on production with nuxt adapter when nitro preset = bun

[Prains]

Environment

"@orpc/client": "^1.8.9",
"@orpc/server": "^1.8.9",
"nuxt": "^4.1.1",

Reproduction

https://github.com/Prains/orpc-nuxt-bun-reproduction

1. bun i
2. bun dev

• open page, everything working correctly

1. bun i
2. bun run build
3. bun run .output/server/index.mjs

• open page, requests return 400 with Malformed request. Ensure the request body is properly formatted and the 'Content-Type' header is set correctly.

Describe the bug

Hey!

When building nuxt project with nitro preset = bun server return 400 on all requests.

After further investigation i figured out that it happens because body of request returns in Unit8 byte instead of parsed body

it is not quite described in nuxt adapter, so im in loss here. is there any options to solve this without any workarouns?

also please add battle pass, awesome library

Additional context

No response

Logs

[dosubot]

This issue happens because Bun's Nitro preset returns the request body as a Uint8Array, but oRPC expects a parsed object or string. The 400 "Malformed request" error is triggered when the body isn't parsed as expected. This is a known limitation—there's no built-in fix in the Nuxt adapter or oRPC for Bun's Uint8Array body format, and it's not documented in the adapter yet.

The recommended solution is to use oRPC's generated client for requests, which ensures the body is formatted correctly for RPCHandler. If you need to support manual API calls (like from Postman or curl), swap RPCHandler for OpenAPIHandler, which is designed to handle standard HTTP requests and avoids this validation error. There are no Bun-specific caveats beyond this—it's about using the right handler for your use case. If you must use RPCHandler with direct calls, you need to implement the full RPC Protocol as documented in oRPC's advanced docs [discussion].

If you need custom body parsing (for example, to handle multipart uploads or raw bodies), you can override the body parser using adapterInterceptors and rootInterceptors, but this is considered a workaround and not a built-in solution [discussion].

Let me know if you want more details on handler setup or body parsing overrides!

To reply, just mention @dosu.

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[dinwwwh]

Let's try fetch adapter instead - https://discord.com/channels/1308966753044398161/1408957813581152316/1416074800258089032

I will check this asap

[Prains]

Let's try fetch adapter instead - https://discord.com/channels/1308966753044398161/1408957813581152316/1416074800258089032

I will check this asap

im sorry discord is currently restricted in my country, can you please send content of the link here?

[Prains]

it did worked out, thank you!!!!

[Prains]

import { RPCHandler } from "@orpc/server/fetch";
import { router } from "../../orpc/router";
import { prismaClient } from "~~/prisma/client";

const handler = new RPCHandler(router);

export default defineEventHandler(async (event) => {
  const request = toWebRequest(event);

  const { matched, response } = await handler.handle(request, {
    prefix: "/rpc",
    context: { prisma: prismaClient, request },
  });

  if (matched && response) return response;

  setResponseStatus(event, 404, "Not Found");

  return "Not found";
});

[Prains]

any chance we get it mentioned in the docs?