Home / Use cases / anthropic-api-budget-cap

Cap Claude API spend per agent — automatic USDC paywall

The problem

You hand an agent your Anthropic API key. It loops, makes 200,000 calls overnight, you wake up to a $4,000 bill. There is no per-agent budget primitive in the upstream API.

What Spawnpay does

Wrap each agent in the Spawnpay paywall SDK with a daily budget. Pre-charge throws BUDGET_DAILY before the call goes upstream. State persists to ~/.spawnpay/budget-state.json with a 24h rolling window.

Code

curl -X POST https://spawnpay.ai/api/proxy\
  -H 'Authorization: Bearer spk_live_...'\
  -H 'Content-Type: application/json' \
  -d '{  "provider": "anthropic",  "path": "/v1/messages",  "method": "POST",  "body": {    "model": "claude-haiku-4-5-20251001",    "max_tokens": 256,    "messages": [      {        "role": "user",        "content": "hello"      }    ]  }}'
60-SEC QUICKSTART → PLAYGROUND → TOP UP USDC →

What you get with $7 free credit

Every new spk_ wallet starts with $7. That covers 7,000 proxy calls, 1,400 cloud-scrapes, or 700 screenshots — enough to verify Spawnpay fits your workflow before topping up.

See also