Open Source API Tools
An application programming interface (API) defines how software systems exchange data and request services. APIs let applications connect without sharing their internal implementation, supporting tasks such as retrieving information, updating records, and coordinating services. They are used in web and mobile applications, automation, data pipelines, and integrations between organizations. Common approaches include REST, GraphQL, and event-driven messaging, each with different patterns for structuring requests and responses.
Open source API tools include server frameworks, client libraries, gateways, documentation generators, testing utilities, and services for monitoring usage. When choosing one, consider its protocol support, security features, licensing, documentation, maintenance activity, runtime requirements, and fit with your existing stack. These tools are useful to developers building integrations or services, as well as teams seeking more control over how software communicates and how API usage is managed.
153 repositories · updated October 15, 2026
shoreguard: Manage NVIDIA OpenShell Agent Sandboxes
ShoreGuard adds a web UI, REST API, and Terraform workflow for managing NVIDIA OpenShell sandboxes, policies, and routed inference. It suits teams operating multiple gateways that need centralized access controls and auditability.
QuietHealth 25/100
meridian: Connect Coding Clients to Claude and Antigravity
Meridian is a local API bridge for using Claude and Antigravity subscriptions with coding clients such as Pi and OpenCode. It also provides usage monitoring and an optional Mac app, with Antigravity currently marked as a preview.
ActiveHealth 77/100
SwarmLLM: Run Local and Distributed AI Models
SwarmLLM runs open AI models on your computer and can pool resources with other computers to run larger models. It also provides OpenAI- and Anthropic-compatible APIs for local apps and agents.
ActiveHealth 46/100
e2a: Email API for Applications and AI Agents
e2a provides an email API and relay for applications and AI agents. It supports transactional sending, inbound mailboxes, and agent replies, with optional human review and hosted or Docker-based deployment.
NewHealth 63/100
shimmy: Serve Local GGUF Models with an OpenAI-Compatible API
Shimmy is a Rust inference server that runs GGUF language models locally and exposes an OpenAI-compatible API. It suits developers who want a lightweight alternative for connecting existing tools to local models without Python or llama.cpp.
ActiveHealth 38/100
router: Route AI Requests to the Best Model
weave-os/router is a Go proxy that routes AI requests across configured model providers, while accepting Anthropic, OpenAI, and Gemini API formats. It suits developers who want model choice and routing behind one endpoint, including agent and coding-tool users.
NewHealth 57/100
llm-d-router: Route Inference Requests Intelligently
llm-d Router directs inference requests using model-serving signals such as KV-cache locality, load, and priority. It is for teams running LLM serving on Kubernetes that need proxy-integrated routing and request flow control.
ActiveHealth 75/100
inference-gateway: Unify LLM Providers Behind One API
Inference Gateway proxies requests to cloud and local LLM providers through compatible APIs. It is suited to teams building provider-flexible AI services that need self-hosting, MCP tools, authentication, or observability.
ActiveHealth 79/100
harnessrouter: Unify Agent Harnesses Behind One API
HarnessRouter is a self-hosted Python service that exposes multiple agent harnesses through a unified, OpenAI Responses-compatible API. It suits teams building agent features that want shared session, streaming, file, and cancellation handling across harnesses.
NewHealth 76/100
aport-spec: Define Pre-Action Authorization for AI Agents
Aport-spec defines Open Agent Passport, a draft standard for checking agent identity and permissions before sensitive actions. It specifies passport and decision formats, signed authorization records, and conformance resources for teams building agent platforms.
MaintainedHealth 30/100
n8n-sandbox-service: Run Commands in Isolated Sandboxes
A Go service that provisions isolated, on-demand environments and exposes command and file operations through a REST API. It is aimed at teams that need to run workloads in containers or Firecracker microVMs behind a central placement service.
NewHealth 68/100
tunnel-client: Connect Private MCP Servers to OpenAI
A Go client that connects private or localhost MCP servers to ChatGPT, Codex, the Responses API, and AgentKit through an OpenAI-hosted tunnel. It is designed for teams that need remote access without exposing MCP servers to the public internet.
ActiveHealth 62/100