Connect-RPC

Connect is a slim framework for building browser-friendly and gRPC-compatible HTTP APIs from Protocol Buffer schemas. Servers built with Connect speak the Connect protocol, gRPC, and gRPC-Web simultaneously, while clients can switch between protocols without changing code. Connect provides type-safe SDKs for Go, TypeScript/JavaScript, Swift, Kotlin, and Python, plus the Buf-generated `protoc-gen-connect-*` code generators. The project is open source under the Apache 2.0 license and is maintained by Buf.

Connect-RPC publishes 5 APIs on the APIs.io network. Tagged areas include Apache 2.0, Buf, Code Generation, Connect Protocol, and gRPC.

Connect-RPC’s developer surface includes documentation, engineering blog, and 8 more developer resources.

🌐 Visit website 📡 Source on GitHub

16.7/100 emerging ▬ flat Agent 3/100 human only Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

AccessFreemium

5 APIs

Apache 2.0BufCode GenerationConnect ProtocolgRPCgRPC-WebHTTP Open-Source Protocol Buffers RPC SDK

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 16.7/100 · emerging

Contract Quality 0.0 / 25

Developer Ergonomics 5.7 / 20

Access Clarity 3.2 / 20

Operational Transparency 1.4 / 13

Contract Governance 0.0 / 12

Discoverability 6.5 / 10

Agent readiness — 3/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/connect-rpc: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 5

Individual APIs this provider publishes, each with its own machine-readable definition.

connect-go

The Go implementation of Connect. Provides server handlers and clients that speak the Connect, gRPC, and gRPC-Web protocols simultaneously. Generated from .proto files via the p...

connect-es (Connect for ECMAScript)

Connect for ECMAScript provides type-safe browser and Node.js clients and Node.js servers from Protobuf schemas. Targets the Connect protocol and gRPC-Web with idiomatic TypeScr...

connect-swift

Connect for Swift provides type-safe Connect, gRPC, and gRPC-Web clients for iOS, macOS, watchOS, and tvOS apps, generated from Protobuf schemas via protoc-gen-connect-swift.

connect-kotlin

Connect for Kotlin provides type-safe clients for Android and JVM applications. Speaks the Connect protocol, gRPC, and gRPC-Web from a single SDK generated by protoc-gen-connect...

connect-python

Connect for Python (beta) provides Connect protocol and gRPC clients generated from Protobuf schemas. Targets ASGI servers and async Python with type-safe stubs.

Pricing Plans 1

Published pricing tiers and plan structures.

Connect Rpc Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Connect Rpc Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Connect Rpc Finops

FINOPS

Security Posture 1

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Connect Rpc Domain Security

TLSv1.3 · HSTS

SECURITY

Resources

Get Started 1

Portal, sign-up, and the first successful call

Demo

Demo

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Operate 1

Status, limits, changes, and where to get help

Slack

Slack

Commercial 1

Pricing, plans, and the legal terms of use

License

License

Company 3

The organization behind the API

Website

Website

Blog

Blog

BlogRSS

BlogRSS

Other 1

Properties that don't map to a standard resource type

Maintainer

Maintainer

Source (apis.yml)

aid: connect-rpc
name: Connect-RPC
description: Connect is a slim framework for building browser-friendly and gRPC-compatible HTTP APIs from Protocol Buffer
  schemas. Servers built with Connect speak the Connect protocol, gRPC, and gRPC-Web simultaneously, while clients can switch
  between protocols without changing code. Connect provides type-safe SDKs for Go, TypeScript/JavaScript, Swift, Kotlin, and
  Python, plus the Buf-generated `protoc-gen-connect-*` code generators. The project is open source under the Apache 2.0 license
  and is maintained by Buf.
type: Index
deliveryModel:
  model: unknown
  open_source: false
  commercial: false
  callable_host: false
  label: Delivery model not determined — needs a product licence on record
  confidence: low
  source:
  - none
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Freemium
  confidence: medium
  source:
  - plans
  generated: '2026-07-22'
  method: derived
position: Producing
access: Open Source
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/connect-rpc.png
url: https://raw.githubusercontent.com/api-evangelist/connect-rpc/refs/heads/main/apis.yml
created: '2026-03-25'
modified: '2026-04-28'
specificationVersion: '0.23'
kind: opensource
tags:
- Apache 2.0
- Buf
- Code Generation
- Connect Protocol
- gRPC
- gRPC-Web
- HTTP
- Open-Source
- Protocol Buffers
- RPC
- SDK
tags_raw:
- Apache 2.0
- Buf
- Code Generation
- Connect Protocol
- gRPC
- gRPC-Web
- HTTP
- Open Source
- Protocol Buffers
- RPC
- SDKs
apis:
- aid: connect-rpc:connect-go
  name: connect-go
  description: The Go implementation of Connect. Provides server handlers and clients that speak the Connect, gRPC, and gRPC-Web
    protocols simultaneously. Generated from .proto files via the protoc-gen-connect-go plugin and designed to slot into idiomatic
    net/http servers.
  humanURL: https://connectrpc.com/docs/go/
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  tags:
  - Go
  - SDK
  properties:
  - type: Documentation
    url: https://connectrpc.com/docs/go/
  - type: GettingStarted
    url: https://connectrpc.com/docs/go/getting-started
  - type: GitHub
    url: https://github.com/connectrpc/connect-go
  - type: Tutorial
    url: https://connectrpc.com/docs/go/tutorial
  x-features:
  - Connect Protocol Server and Client
  - gRPC Compatibility
  - gRPC-Web Compatibility
  - Streaming RPCs
  - Interceptors
  - Idiomatic net/http Integration
  x-use-cases:
  - Build a Go service callable from browsers and gRPC clients
  - Migrate gRPC services to Connect without breaking clients
  - Add HTTP/JSON access to existing Protobuf services
- aid: connect-rpc:connect-es
  name: connect-es (Connect for ECMAScript)
  description: Connect for ECMAScript provides type-safe browser and Node.js clients and Node.js servers from Protobuf schemas.
    Targets the Connect protocol and gRPC-Web with idiomatic TypeScript types and tree-shakable output.
  humanURL: https://connectrpc.com/docs/web/
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  tags:
  - JavaScript
  - SDK
  - TypeScript
  properties:
  - type: Documentation
    url: https://connectrpc.com/docs/web/
  - type: GettingStarted
    url: https://connectrpc.com/docs/web/getting-started
  - type: GitHub
    url: https://github.com/connectrpc/connect-es
  x-features:
  - Browser Clients
  - Node.js Clients
  - Node.js Servers
  - Tree-Shakable Bundles
  - Type-Safe TypeScript
  - gRPC-Web Compatibility
  x-use-cases:
  - Call Protobuf services from React, Vue, or vanilla JS
  - Build Node.js servers without a gRPC dependency
  - Share TypeScript types between client and server
- aid: connect-rpc:connect-swift
  name: connect-swift
  description: Connect for Swift provides type-safe Connect, gRPC, and gRPC-Web clients for iOS, macOS, watchOS, and tvOS
    apps, generated from Protobuf schemas via protoc-gen-connect-swift.
  humanURL: https://connectrpc.com/docs/swift/
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  tags:
  - iOS
  - SDK
  - Swift
  properties:
  - type: Documentation
    url: https://connectrpc.com/docs/swift/
  - type: GettingStarted
    url: https://connectrpc.com/docs/swift/getting-started
  - type: GitHub
    url: https://github.com/connectrpc/connect-swift
  x-features:
  - URLSession Integration
  - Streaming Support
  - gRPC and gRPC-Web Clients
  - Async/Await API
  x-use-cases:
  - Call Protobuf services from iOS apps
  - Add streaming RPC to Apple platform clients
- aid: connect-rpc:connect-kotlin
  name: connect-kotlin
  description: Connect for Kotlin provides type-safe clients for Android and JVM applications. Speaks the Connect protocol,
    gRPC, and gRPC-Web from a single SDK generated by protoc-gen-connect-kotlin.
  humanURL: https://connectrpc.com/docs/kotlin/
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  tags:
  - Android
  - JVM
  - Kotlin
  - SDK
  properties:
  - type: Documentation
    url: https://connectrpc.com/docs/kotlin/
  - type: GettingStarted
    url: https://connectrpc.com/docs/kotlin/getting-started
  - type: GitHub
    url: https://github.com/connectrpc/connect-kotlin
  x-features:
  - Coroutines API
  - OkHttp Transport
  - Streaming Support
  - Multi-Protocol Client
  x-use-cases:
  - Call Protobuf services from Android apps
  - Share Kotlin types across mobile and backend
- aid: connect-rpc:connect-python
  name: connect-python
  description: Connect for Python (beta) provides Connect protocol and gRPC clients generated from Protobuf schemas. Targets
    ASGI servers and async Python with type-safe stubs.
  humanURL: https://connectrpc.com/docs/python/
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  tags:
  - Python
  - SDK
  properties:
  - type: Documentation
    url: https://connectrpc.com/docs/python/
  - type: GitHub
    url: https://github.com/connectrpc/connect-python
  x-features:
  - ASGI Integration
  - Type-Safe Stubs
  - Connect and gRPC Clients
  x-use-cases:
  - Add Protobuf RPC to Python services
  - Call Connect services from data-science notebooks
common:
- type: DomainSecurity
  url: security/connect-rpc-domain-security.yml
- type: Website
  url: https://connectrpc.com
- type: Documentation
  url: https://connectrpc.com/docs/introduction
- type: GitHubOrganization
  url: https://github.com/connectrpc
- type: Demo
  url: https://connectrpc.com/demo
- type: Blog
  url: https://buf.build/blog
- url: https://buf.build/blog/rss.xml
  type: BlogRSS
  description: Discovered RSS/Atom feed for https://buf.build/blog
- type: Maintainer
  url: https://buf.build
- type: License
  url: https://github.com/connectrpc/connect-go/blob/main/LICENSE
- type: Slack
  url: https://buf.build/links/slack
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

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