Expedia Group Rapid API vs LetsFG

Expedia Group Rapid API

Expedia's lodging inventory with shop, price check, book, change and cancel in one API. Partner application and site review before production, no self-serve keys.

LetsFG

Hosted MCP with OAuth 2.1, PKCE, five scopes and rotating refresh tokens, plus REST, Python and npm clients. Tickets are bought by a LetsFG booking agent after the hold, 4 to 11 minutes per the docs, and bookings can pause with questions.

Expedia Group Rapid API

1. Build the SHA-512 signature from key, secret and the current epoch seconds in that order, per request
2. Send Customer-Ip and the session headers the docs ask for, since fraud checks use them
3. Point everything at test.ean.com until the site review is through; the paths match api.ean.com
4. Follow the links in each response rather than building URLs; price check and book links carry tokens
5. Read the Rate-Limit-Minute-Remaining and Rate-Limit-Day-Remaining headers, since the docs publish no ceilings

LetsFG

1. Start on /v1/sandbox/ with no key; the booking states, questions and timings match production
2. After book_flight, poll get_flight_booking every 20 to 30 seconds and answer questions before expires_at_ms; an unanswered price change fails the booking and releases the hold
3. Honour retry_after_seconds on a 429. Over MCP the limit is 10 searches per 10 minutes and 100 a day, and early retries lengthen the pause
4. Fetch results with get_flight_results and the search_id rather than searching again, which spends allowance
5. Send the same idempotency_key when retrying a booking after a timeout
6. Treat a 410 as a retired route and read the replacement path in its body