Docs · 2026-05-29

TL;DR — Set ANTHROPIC_BASE_URL=https://api.jusinfer.com and ANTHROPIC_AUTH_TOKEN=jinf_... in your shell. jusInfer speaks the Anthropic Messages API natively at /v1/messages — Claude Code's default — and routes every call to the cheapest capable model under the hood.

Use jusInfer with Claude Code

Claude Code is Anthropic's terminal-native coding agent. It speaks the Anthropic Messages API (POST /v1/messages) by default. jusInfer exposes that exact surface — so Claude Code points at api.jusinfer.com with one env-var change and everything else (tool use, streaming, thinking, system prompts) keeps working unchanged. Under the hood, jusInfer routes each call to the cheapest capable model.

Why route through jusInfer?

Cost. We pick the most cost-effective model that meets the bar for each call — frontier when you need it, smaller when you don't. Same API, lower bill.
No vendor lock-in. Your code only ever talks to api.jusinfer.com. We swap models behind the scenes as the market moves.
One bill. Credits roll over, never expire. Per-user soft caps. No surprise overages.
Same DX. Your existing Claude Code workflow doesn't change — just the endpoint.

30-second setup

1. Get a jusInfer API key

# Sign in at https://jusinfer.com/login (Google or Microsoft)
# Then visit https://jusinfer.com/developer → Keys tab → "Mint key"
# Copy the jinf_… token. You'll only see it once.

2. Point Claude Code at jusInfer

Claude Code uses two environment variables for OpenAI-compatible mode:

export ANTHROPIC_BASE_URL="https://api.jusinfer.com"
export ANTHROPIC_AUTH_TOKEN="jinf_your_key_here"

Add those to your shell profile (~/.zshrc, ~/.bashrc) and reload:

source ~/.zshrc

3. Verify

claude --version
claude  # should start a normal session

Inside Claude Code, ask it anything — say, "summarize this directory". The call is routed through jusInfer. Verify the spend on your dashboard.

Per-project override

If you only want jusInfer for one repo:

# Create .envrc in your repo (with direnv) or a shell alias:
alias claude-jusinfer='ANTHROPIC_BASE_URL=https://api.jusinfer.com \
  ANTHROPIC_AUTH_TOKEN=jinf_... claude'

What jusInfer picks

jusInfer routes every request through three filters:

Capability — does the task need hard reasoning, long context, or tool use?
Cost — per-token rate, cache hit rate, retry cost
Fit — task type, codebase size, your spend profile

The chosen model is opaque by default. You can inspect any call's actual upstream model from the Usage tab if you want to.

Limits and gotchas

Streaming works. Server-sent events are forwarded transparently.
Tool use works. Both Anthropic-style and OpenAI-style tool calls are normalized.
System prompts work. No magic — they pass through untouched.
Image inputs route to a vision-capable model automatically.
Rate limits: 60 RPM per key, 600 RPM per tenant. Bump in the dashboard if you need more.

Troubleshooting

Symptom	Likely cause	Fix
`401 INVALID_KEY`	Key was revoked or never minted	Mint a fresh key in the dashboard
`403 SEAT_REQUIRED`	Tenant has >1 member with no seat sub	Subscribe in Billing tab
`429 RATE_LIMIT`	Burst hit the per-key 60 RPM	Wait 60s or raise the limit
`502`	Upstream model temporarily unavailable	Retry; jusInfer automatically falls back

This page is also available as raw markdown for AI agents to consume directly: /docs/claude-code.md