SerpApi vs Tavily API + MCP

SerpApi

Over 100 engines behind one GET URL, with json_restrictor field selection and output=md. 25 incidents on the status feed from July to 1 October 2026, including an outage across all APIs on 10 September.

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.

SerpApi

1. Use the MCP with Authorization: Bearer, not the key-in-path URL the README leads with
2. Read serpapi://engines/<engine> before calling a new engine, since params isn't typed
3. Add json_restrictor or output=md to cut tokens, and mode: compact on the MCP
4. A 429 means either the hourly limit or an empty balance. Check the account before retrying
5. Repeat a search within the hour and the cached copy is free. Set no_cache=true only when freshness matters

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}