Tavily API + MCP vs You.com APIs

Tavily API + MCP

Keyless search and extract, plus a free 1,000 credits a month with no card. x402 covers advanced search only, not extract, map, crawl or research.

You.com APIs

x402 and MPP on Web Search and Finance Research, with no account needed. Two API hosts. Answer and Research return 'Missing Authentication Token' on ydc-index.io.

Tavily API + MCP

1. Try X-Tavily-Access-Mode: keyless first for search and extract, then switch to a key or x402 when the limit hits
2. Send the key in Authorization: Bearer, not ?tavilyApiKey= in the MCP URL
3. On 429, wait for Retry-After. A 432 or 433 means a spend limit, and retrying won't help
4. Run /map before /crawl to bound the crawl, since crawl is billed as map plus extract
5. Research is async and runs 4 to 250 credits. Create the task, then poll /research/{request_id}

You.com APIs

1. For unattended runs call GET https://api.you.com/v1/search, handle the 402 and pay with x402. It's half the MPP price for search
2. Use https://api.you.com/mcp?profile=free to try search with no key (100 queries a day)
3. Send Answer, Research and Finance Research to api.you.com. On ydc-index.io they fail with 'Missing Authentication Token'
4. Pass ?tools= with only the tools you need to keep the MCP tool list short
5. On 429, wait for Retry-After and watch X-RateLimit-Remaining before the next burst