LLM InterceptorLocal-first, open-source LLM gateway

Transparent proxy · OpenTelemetry observability · Governance (budget/rate-limit/tool-policy) Multi-provider routing · Protocol translation (Anthropic ↔ OpenAI) · React SPA dashboard

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Transparent Proxy

Drop-in replacement for Anthropic Messages API and OpenAI Chat API. Works with Claude Code, Cline, OpenCode, and any SDK.

Plugin Architecture

Extend behavior via Go interfaces — OTel, cost tracking, rate limiting, tool policies. Forward path never blocked.

Observability

OpenTelemetry traces and metrics. Prometheus endpoints. Token usage, latency (TTFT, P50/P95/P99), error rates, active requests.

Governance

Per-key budgets, rate limiting (RPM/TPM), tool-use policies. Best-effort alerting via Slack, Webhook, or Email.

LLM Router

Auto-detect provider from API key prefix (sk-lli-*). Multi-tenant key management with bcrypt. Bidirectional protocol translation.

Web UI

React SPA with dashboards for requests, sessions, cost analytics, error analysis, and admin console. SSE live events. Export to CSV/JSON.

Protocol Translation

Full bidirectional Anthropic ↔ OpenAI. Streaming SSE translation, tool calls, thinking blocks, system prompt mapping.

Single Binary

One Go binary. SQLite or PostgreSQL. In-memory or Redis. Docker Compose one-click start with no external dependencies.

bash — llm-interceptor

$git clone https://github.com/chingjustwe/llm-interceptor.git
Cloning into 'llm-interceptor'... ✓
$cd llm-interceptor && go build -o llm-interceptor ./cmd/llm-interceptor/
✓ Binary built (13 MB)
$./llm-interceptor config.example.yaml
[server] Listening on 127.0.0.1:8080
[plugins] Loaded: otel, cost-tracker, budget, rate-limit, tool-policy
[router] Mode: passthrough (upstream: api.anthropic.com)
$

How it works

A transparent proxy between your application and LLM providers, with a plugin pipeline for observability and governance.

AppSDK / HTTP

LLM Interceptor

OTelCostBudgetRate LimitTool Policy

StorageSQLite / PG

StateMemory / Redis

ProviderAnthropic / OpenAI