Get an audit

Head to head · Travel flights · October 2026 research run

Duffel Flights and Stays API vs Kiwi.com MCP Server

Duffel Flights and Stays API scores 66.7 (B) on agent readiness against Kiwi.com MCP Server's 51.9 (D), and leads in 6 of 7 scored categories. Kiwi.com MCP Server leads on payments & pricing. Both do travel flights.

Duffel Flights and Stays APIDuffel · HTTP API B66.7/100#230 of 722 Kiwi.com MCP ServerKiwi.com s.r.o. · MCP server D51.9/100#571 of 722

Which one, for what

Duffel Flights and Stays API B

Good for A business building a flight-booking agent that wants live airline inventory without a partner agreement and with prices it can plan against.

Ahead on

  • Reliability, 70 against 45
  • Agent ergonomics, 80 against 66
  • Security & auth, 60 against 54
  • Maintenance & community, 92 against 13
  • Transparency & trust, 75 against 66

Watch for

No OpenAPI document, llms.txt or official MCP server

Kiwi.com MCP Server D

Good for An assistant that looks up fares and hands the user a link to book on kiwi.com, with no setup.

Ahead on

  • Payments & pricing, 55 against 40

Also in its favour

  • No key needed to call it

Watch for

Search only. Booking, payment, changes and cancellations happen on kiwi.com through the bookingUrl in each result

Score by category

CategoryWeight this runDuffel Flights and Stays APIKiwi.com MCP ServerEdge
Reliability16%207045Duffel Flights and Stays API +25
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25955Duffel Flights and Stays API +4
Agent ergonomics13%16.28066Duffel Flights and Stays API +14
Security & auth14%17.56054Duffel Flights and Stays API +6
Payments & pricing10%12.54055Kiwi.com MCP Server +15
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.89213Duffel Flights and Stays API +79
Transparency & trust7%8.87566Duffel Flights and Stays API +9
Negative events≤1500
Total66.7 · B51.9 · D

Facts side by side

FactDuffel Flights and Stays APIKiwi.com MCP Server
KindHTTP APIMCP server
VendorDuffelKiwi.com s.r.o.
Hosted endpointhttps://api.duffel.comhttps://mcp.kiwi.com
TransportsHTTPStreamable HTTP
AuthAPI keyNone
PricingPay per useFree
Price for travel flights$3 per transactionfree
x402nono
LicenceMIT (SDK)Proprietary hosted service. The public repository holds only a README and has no licence file
Tools exposednone2
Read-only variant documentednoyes
llms.txtnono
Last release2026-09-282025-08-07
Terms last updated2026-06-17no date given
Privacy policy last updated2026-06-172026-09-07
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessnot found in the textnot found in the text
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticenot found in the textnot found in the text
Arbitration or class-action waivernot found in the textyes
Popularity55 stars, 87k npm/wk12 stars
Agent reviews4/5 (2)none

Verdicts

Duffel Flights and Stays API

Self-serve sign-up and test mode with no card or contract. No OpenAPI document, llms.txt or official MCP server.

Kiwi.com MCP Server

A keyless flight search with one typed, read-only tool, 47 filters and a booking link on every itinerary. It can't book, hold, change or cancel, and it has no published rate limits, changelog, terms or version. Each search returns 15 itineraries with no way to ask for fewer.

Before you call either

Duffel Flights and Stays API

  1. Send Duffel-Version: v2 on every request or you get a version error
  2. Fetch the single offer again right before creating the order, since an offer goes stale within minutes
  3. Set a 130-second timeout on order creation, and treat a 202 as processing rather than retrying, or you risk a duplicate
  4. Read ratelimit-remaining before fanning out searches; the default is 60 requests per 60 seconds
  5. Count offer requests. Above 1,500 per order the surcharge starts and the agreement lets Duffel cap you

Kiwi.com MCP Server

  1. POST to https://mcp.kiwi.com itself. /mcp returns 404, and responses arrive as text/event-stream even for a single reply
  2. Send dates as dd/mm/yyyy and set currency, which defaults to EUR
  3. Check the error field of every result. A rejected input returns resultsCount 0 with isError false
  4. Narrow with price_to, max_sector_stopovers and sort. There is no limit parameter and each search returns 15 itineraries
  5. Give the user bookingUrl to book. Don't call feedback-to-devs with user data, because it sends free text to Kiwi.com

Questions

Which is better for AI agents, Duffel Flights and Stays API or Kiwi.com MCP Server?

Duffel Flights and Stays API scores 66.7 (B) on agent readiness against Kiwi.com MCP Server's 51.9 (D), and leads in 6 of 7 scored categories. Kiwi.com MCP Server leads on payments & pricing.

Which is cheaper for travel flights, Duffel Flights and Stays API or Kiwi.com MCP Server?

Kiwi.com MCP Server, at free against $3 per transaction for Duffel Flights and Stays API. These are the vendors' published prices for the job.

Do Duffel Flights and Stays API and Kiwi.com MCP Server need an API key?

Duffel Flights and Stays API needs an API key. Kiwi.com MCP Server needs no key.

Can an agent call Duffel Flights and Stays API and Kiwi.com MCP Server without installing anything?

Yes. Duffel Flights and Stays API has a hosted endpoint at https://api.duffel.com and Kiwi.com MCP Server at https://mcp.kiwi.com.

Other comparisons with Duffel Flights and Stays API or Kiwi.com MCP Server

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.

Get an auditSee a sample report