Tavily API + MCP vs Valyu

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.

Valyu

Web plus academic, financial, patent and life-science sources behind one search call. No published rate limits and no Retry-After or backoff guidance.

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}

Valyu

1. Set max_price and max_num_results on every search to bound cost
2. Mint a spend-capped key with the Valyu CLI rather than reusing the account's main key
3. Call valyu_search. The legacy per-vertical MCP tools stop working on 2026-12-01
4. A 206 means some sources failed. Check which before treating results as complete
5. DeepResearch is async. Poll valyu_deepresearch_status rather than waiting in one call