SpendFuel spendfuel.app

How to Find x402 Tools with the SpendFuel API

· 2 min read

SpendFuel's JSON API is public and needs no key. It is a quick way for a script or an agent to find a paid tool that fits a job and a budget. All endpoints live under https://spendfuel.app/api/v1, and the full contract is in openapi.yaml.

1. Search the catalog

curl -s 'https://spendfuel.app/api/v1/catalog?q=search&max_price=0.05&sort=price&limit=10'

Query parameters:

  • q: free-text search
  • category: for example search, data, vision or compute
  • max_price: highest price per call in USD
  • verified: true to show verified listings only
  • sort: rank, price, success_rate or newest
  • limit (1 to 100, default 50) and offset for paging

Each result includes the tool's slug, name, description, url, mcp_url if it has one, price_usd, pricing_model, category, tags, verified and source (for example manual or auto-seed).

2. See what categories exist

curl -s https://spendfuel.app/api/v1/catalog/categories

Returns each category with a count, which is handy for building a filter or telling an agent what is available.

3. Ask for a recommendation

curl -s 'https://spendfuel.app/api/v1/recommend?goal=web+search&budget_usd=0.05&limit=3'

Give a goal in plain words and a per-call budget. You get back a short list of tools that match the goal and fit the budget. This is the endpoint to use when an agent has a spending cap.

4. Read one tool

curl -s https://spendfuel.app/api/v1/tools/exa-search

Full details for a single listing by slug.

Tips

  • Catalog responses are cached for about 30 seconds (Cache-Control: max-age=30), so a brand-new listing can take a moment to appear.
  • Prefer verified listings when reliability matters, and remember that auto-seeded listings are unverified: SpendFuel confirmed the endpoint answered with an x402 payment challenge, not that the tool is good.
  • Always confirm the live price with the provider before your agent pays. Listing prices can lag behind provider changes.
  • GET /api/v1/health is a simple liveness check.

Prefer MCP? See connect your agent to SpendFuel over MCP. New here? Start with what SpendFuel is.

Keep reading