Quick start — Cloud

Start free

Create an account at lair.prxy.monster/sign-up. Free includes 1,000 requests/month.

Get a PRXY API key

Mint or copy a key in Lair. Keys look like:

prxy_live_a1b2c3d4e5f6...

Configure provider access

BYOK means your upstream provider bills you directly. You can register provider keys in Lair, or pass a provider key for supported requests with x-provider-key.

curl https://api.prxy.monster/v1/byok/anthropic \
  -X PUT \
  -H "Authorization: Bearer $PRXY_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "apiKey": "sk-ant-..." }'

Point your app at the gateway

export ANTHROPIC_BASE_URL=https://api.prxy.monster
export ANTHROPIC_API_KEY=prxy_live_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

import Anthropic from '@anthropic-ai/sdk';
 
const client = new Anthropic();
 
const msg = await client.messages.create({
  model: 'claude-sonnet-4-6',
  max_tokens: 256,
  messages: [{ role: 'user', content: 'hi' }],
});

export OPENAI_BASE_URL=https://api.prxy.monster/v1
export OPENAI_API_KEY=prxy_live_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

import OpenAI from 'openai';
 
const client = new OpenAI();
 
const r = await client.chat.completions.create({
  model: 'gpt-4o-mini',
  messages: [{ role: 'user', content: 'hi' }],
});

curl https://api.prxy.monster/v1/messages \
  -H "Authorization: Bearer $PRXY_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-6",
    "max_tokens": 256,
    "messages": [{"role": "user", "content": "hi"}]
  }'

Verify the pipeline

curl https://api.prxy.monster/v1/pipeline \
  -H "Authorization: Bearer $PRXY_KEY"

Default:

{
  "configured": [],
  "active": [
    { "name": "mcp-optimizer", "version": "1.0.0" },
    { "name": "semantic-cache", "version": "1.0.0" },
    { "name": "patterns", "version": "1.0.0" }
  ],
  "override": null
}

Cache short-circuits set an x-prxy-cache response header naming the module that returned the cached result.

Optional: try MPP discovery

Agents without a prxy key can inspect the MPP surface:

curl https://api.prxy.monster/.well-known/mpp

Discovery, the HTTP 402 challenge flow, /v1/agent/quote, and /v1/agent/sessions are live end-to-end. Production Stripe SPT settlement is gated on Stripe Link SPT GA + production-payment credentials. Until that is configured, paid retries can return verification-failed. See Agent payments.