feat(trpc): tRPC integration

[dinwwwh]

Summary

Brings the tRPC integration (@orpc/trpc) to v2. You can now convert a tRPC router into an oRPC router and use it with any oRPC feature:

const orpcRouter = toORPCRouter(trpcRouter)

• Works with RPC/OpenAPI handlers, server-side clients, OpenAPI spec generation, subscriptions (including tracked events), and lazy routers
• toTRPCMeta lets you use oRPC meta plugins (like openapi(...)) directly in tRPC's .meta()
• New tRPC Integration docs page
• 100% test coverage

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Project	Deployment	Actions	Updated (UTC)
orpc	Ready	Preview, Comment	Jul 19, 2026 3:22am

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commit: fe44c11

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[codspeed-hq]

Merging this PR will not alter performance

✅ 18 untouched benchmarks

---

_{Comparing dinwwwh:claude/orpc-v2-trpc-integration-3b6f96 (fe44c11) with main (61ef170)}

[pullfrog]

ℹ️ Minor suggestions only. Package type-checks and all 11 new tests pass.

Reviewed changes — port of the @orpc/trpc package from v1 to v2, adding toORPCRouter to convert tRPC routers into oRPC routers, plus tests and docs.

• Add @orpc/trpc package with toORPCRouter, ORPCMeta, and ToORPCRouterResult type mapping.
• Adapt to v2 architecture by preserving tRPC schemas while disabling oRPC validation, forwarding meta (including ~openapi), wrapping TRPCError as ORPCError, and supporting lazy/subscription routers.
• Add docs and fix migration link with a new docs/integrations/trpc.md page and corrected sidebar entry.

Feedback

• packages/trpc/package.json:39 — ⚠️ The package imports from @trpc/server/unstable-core-do-not-import for parser/iterator helpers, but the peer dependency has no upper bound. Because the unstable namespace is explicitly semver-exempt, a future tRPC v12 could break this integration. Consider "@trpc/server": ">=11.4.2 <12".

• packages/trpc/src/to-orpc-router.ts:126 — ℹ️ isObject(input) is also true for arrays, so a subscription input that is an array would be converted to { '0': ..., lastEventId }. Consider guarding with !Array.isArray(input) if array inputs are supported.

• packages/trpc/src/to-orpc-router.ts:137-138 — ℹ️ batchIndex: 0 is hard-coded with a TODO, so converted procedures won't behave correctly under the oRPC Batch Plugin. Worth tracking if batch plugin support is a goal.

• apps/content/docs/integrations/trpc.md:118 — ℹ️ The error-formatting snippet uses z.ZodError, z.prettifyError, and z.flattenError but doesn't show a zod import. Adding it keeps the example copy-pasteable.

  ^{｜ View workflow run ｜ via Pullfrog ｜ Using Kimi K2 (free via Pullfrog for OSS) ｜ 𝕏}

[pullfrog]

test comment 2

  ^{｜ View workflow run ｜ via Pullfrog ｜ Using Kimi K2 (free via Pullfrog for OSS) ｜ 𝕏}

[pullfrog]

ℹ️ Minor suggestions only. Package type-checks and all 11 new tests pass.

Reviewed changes — port of the @orpc/trpc package from v1 to v2, adding toORPCRouter to convert tRPC routers into oRPC routers, plus tests and docs.

• Add @orpc/trpc package with toORPCRouter, ORPCMeta, and ToORPCRouterResult type mapping.
• Adapt to v2 architecture by preserving tRPC schemas while disabling oRPC validation, forwarding meta (including ~openapi), wrapping TRPCError as ORPCError, and supporting lazy/subscription routers.
• Add docs and fix migration link with a new docs/integrations/trpc.md page and corrected sidebar entry.

  ^{｜ Fix all ➔ ｜ Fix 👍s ➔ ｜ View workflow run ｜ Using Kimi K2 (free via Pullfrog for OSS) ｜ 𝕏}

[pullfrog]

Important

The latest commits address some prior feedback (drop ORPCMeta, add mapMeta, reach 100% test coverage), but a few open concerns from the last review remain unresolved. I can't approve until they're addressed or explicitly accepted.

Reviewed changes — since the prior review, the package replaced the built-in ORPCMeta type with explicit '~openapi' typing and a user-supplied mapMeta option, and added tests covering dot-path lazy routers, partially loaded routers, scalar lastEventId input passthrough, and non-TRPCError rethrowing. Type-check and the 15 runtime tests pass.

  ^{｜ Fix all ➔ ｜ Fix 👍s ➔ ｜ View workflow run ｜ Using Kimi K2 (free via Pullfrog for OSS) ｜ 𝕏}

[pullfrog]

Important

The new toTRPCMeta bridge is clean, but I cannot approve while three unresolved Pullfrog concerns remain on the tRPC package.

Reviewed changes — since the last review, the package added the toTRPCMeta helper so oRPC meta plugins can be used with tRPC builders, plus tests and docs.

• Added toTRPCMeta in packages/trpc/src/to-trpc-meta.ts, wrapping resolveMetaPlugins from @orpc/contract to resolve oRPC meta plugins into a plain meta object.
• Added @orpc/contract dependency and exported the new helper from packages/trpc/src/index.ts.
• Added tests covering empty-plugin resolution, plugin merge logic, custom defineMeta plugins, and end-to-end conversion with toORPCRouter.
• Updated docs/integrations/trpc.md to promote toTRPCMeta first and document the shallow-merge caveat of chained tRPC .meta() calls.
• Resolved the previously open isObject(input)/lastEventId array-input concern by verifying that tRPC's isObject explicitly excludes arrays.

⚠️ @trpc/server peer dependency lacks an upper bound

packages/trpc/package.json declares "@trpc/server": ">=11.4.2". Because the code imports from @trpc/server/unstable-core-do-not-import, a future tRPC semver-major release could break the integration without a compatibility signal.

⚠️ Docs error-formatting snippet is missing imports

apps/content/docs/integrations/trpc.md uses z.ZodError, z.prettifyError, and z.flattenError in its error-formatting example, but the zod import is not shown, so the snippet is not copy-pasteable.

⚠️ batchIndex: 0 is hard-coded

packages/trpc/src/to-orpc-router.ts always passes batchIndex: 0 to tRPC procedures, with a TODO noting it should be inferred from context. Converted procedures will not behave correctly under the oRPC Batch Plugin.

  ^{｜ Fix it ➔ ｜ View workflow run ｜ Using Kimi K2 (free via Pullfrog for OSS) ｜ 𝕏}

[pullfrog]

Important

No new issues in the latest commit, but this PR still cannot be approved until the unresolved Pullfrog review threads from the previous review are addressed.

Reviewed changes — the latest commit reorganized docs/integrations/trpc.md so the general router-conversion content comes before the OpenAPI section.

• Moved router conversion to its own section explaining that the result is a regular oRPC router compatible with handlers, clients, middlewares, plugins, and interceptors.
• Added call and createRouterClient examples showing direct procedure invocation and server-side clients.
• Added an info box noting that input/output validation remains delegated to tRPC.

  ^{｜ Fix it ➔ ｜ View workflow run ｜ Using Kimi K2 (free via Pullfrog for OSS) ｜ 𝕏}

[pullfrog]

Important

The latest commit is clean, but three unresolved concerns from prior reviews remain unaddressed.

Reviewed changes — since the prior review at f6298018, the package dropped the optional mapMeta API and the tRPC integration docs were trimmed.

• Removed the mapMeta option from toORPCRouter: meta now passes straight through from tRPC, and users are expected to put OpenAPI metadata under '~openapi' (typically via toTRPCMeta).
• Simplified the OpenAPI docs section by removing the manual OpenAPIMeta example and the request-handling code block; the page now links to the dedicated OpenAPI docs.
• Removed the mapMeta test case and kept the rest of the test suite passing (18 tests).

  ^{｜ Fix all ➔ ｜ Fix 👍s ➔ ｜ View workflow run ｜ Using Kimi K2 (free via Pullfrog for OSS) ｜ 𝕏}

[pullfrog]

Important

The latest commit simplifies conversion internals, but it drops support for nested lazy routers and leaves a stale project reference.

Reviewed changes — since the prior review at 664a7954, the latest commit refactored lazy conversion and call forwarding.

• Removed the @orpc/client dependency and switched from wrapAsyncIteratorPreservingEventMeta to @orpc/shared's wrapAsyncIterator while preserving event metadata explicitly.
• Simplified lazy-router conversion by removing the accessible-proxy wrapper.
• Added opaqueReturnedErrors: true to converted procedures.
• Strengthened call tests to assert context, signal, path, type, and raw input forwarding.

  ^{｜ Fix all ➔ ｜ Fix 👍s ➔ ｜ View workflow run ｜ Using Kimi K2 (free via Pullfrog for OSS) ｜ 𝕏}

[pullfrog]

Important

The latest commit is clean and the stale tsconfig.json reference is fixed, but several Pullfrog concerns from prior reviews remain unaddressed — most notably, nested lazy routers placed under plain object records are still inaccessible at runtime.

Reviewed changes — since the prior Pullfrog review at 77141d7, the PR cleaned up tests, removed the stale ../client project reference, loosened the toTRPCMeta return type, and restructured the tRPC integration docs. Type-check and the 15 runtime tests pass.

• Restructured apps/content/docs/integrations/trpc.md to lead with router conversion and error formatting before covering toTRPCMeta in a dedicated Metadata section.
• Removed the stale ../client project reference from packages/trpc/tsconfig.json after @orpc/client was removed as a dependency.
• Loosened toTRPCMeta’s return type from Meta to Record<string, any> in packages/trpc/src/to-trpc-meta.ts so it can be passed directly to tRPC .meta() calls with arbitrary user-defined meta shapes.
• Inlined test routers in packages/trpc/src/to-orpc-router.test.ts and packages/trpc/src/to-orpc-router.test-d.ts and removed the shared fixture to avoid cross-test coupling.
• Restored the non-TRPCError rethrow test using a mutation that returns an async iterable whose iterator factory throws the original error.

⚠️ Nested lazy routers under plain object records remain inaccessible

A runtime reproduction confirms the issue raised in the previous review is still present: tRPC stores a lazy placed under a plain record (nested: { lazy: lazy(...) }) with the dot-joined key nested.lazy. lazyToORPCRouter assigns that key verbatim, so orpcRouter.nested.lazy is undefined while (orpcRouter as any)['nested.lazy'] is the Lazy. The existing deep lazy test only covers lazies inside lazy-loaded sub-routers, not this plain-record case.

⚠️ @trpc/server peer dependency still lacks an upper bound

packages/trpc/package.json:39 still declares "@trpc/server": ">=11.4.2". Because this package imports from @trpc/server/unstable-core-do-not-import, a future tRPC semver-major release could break the integration without a compatibility signal.

⚠️ batchIndex: 0 remains hard-coded

packages/trpc/src/to-orpc-router.ts:110-111 still passes batchIndex: 0 to tRPC procedures, so converted procedures will not behave correctly under the oRPC Batch Plugin.

ℹ️ Nitpicks

• apps/content/docs/integrations/trpc.md:58 still uses z.ZodError, z.prettifyError, and z.flattenError without showing the imports (zod, ORPCError, TRPCError), so the error-formatting snippet is not copy-pasteable.

  ^{｜ Fix it ➔ ｜ View workflow run ｜ Using Kimi K2 (free via Pullfrog for OSS) ｜ 𝕏}

[pullfrog]

Important

The latest commit resolves the nested lazy-router issue from the previous review. Type-check and all 15 runtime tests pass, and I found no new issues in this increment. This PR still carries unresolved Pullfrog feedback from the prior review, so it is not yet mergeable.

Reviewed changes — since the prior Pullfrog review at b38745d, the latest commit fixes nested lazy routers placed under plain object records.

• Fixed nested lazy-router placement in packages/trpc/src/to-orpc-router.ts by splitting tRPC's dot-joined lazy keys with set from @orpc/shared, so orpcRouter.nested.lazy is now accessible at runtime.
• Added/updated tests in packages/trpc/src/to-orpc-router.test.ts covering deep lazy-loaded sub-routers and lazies nested under plain object records.

  ^{｜ Fix it ➔ ｜ View workflow run ｜ Using Kimi K2 (free via Pullfrog for OSS) ｜ 𝕏}