# Heathrow Airport

> Heathrow Airport Limited operates London Heathrow (IATA LHR, ICAO EGLL), the United Kingdom's principal international hub and Europe's busiest airport by passenger numbers. Heathrow runs a real, branded developer portal at developer.heathrow.com built on Microsoft Azure API Management, which publicly describes three API products in prose — Flights, Flight Connections and Weather — but publishes no OpenAPI, no endpoint reference, no rate limits, no pricing and no SLA to anonymous visitors. Access requires a manual enrolment conversation, a Microsoft Entra ID (Azure AD) account, and a Heathrow-issued client certificate for the mutual-TLS gateway at api.heathrow.com.

This file was generated by API Evangelist from the public Heathrow surface on 2026-07-28. Heathrow publishes no llms.txt of its own (developer.heathrow.com/llms.txt and www.heathrow.com/llms.txt both 404).

## APIs

- [Heathrow Flights API](https://developer.heathrow.com/api-flights): Real-time flight information to and from Heathrow — destinations, arrivals, airlines, aircraft types, flight status, gates and terminals, with scheduled flights enriched by real-time gate and terminal updates. Contract visible only to enrolled, Azure AD authenticated accounts.
- [Heathrow Flight Connections API](https://developer.heathrow.com/api-connections): Real-time flight connections to and from Heathrow, returning connection information together with flight detail. Four documented query shapes — flight to flight, flight to terminal, terminal to terminal, terminal to flight.
- [Heathrow Weather API](https://developer.heathrow.com/api-weather): Weather conditions at most airports worldwide — temperature, weather categories, a countries list, and weather lookup by IATA code. Positioned as a companion to the Flights API.

## Specs

No machine-readable contract is published. No OpenAPI, Swagger, AsyncAPI, GraphQL schema, JSON Schema or Postman collection is retrievable anonymously anywhere on heathrow.com, developer.heathrow.com, api.heathrow.com or apimgmt.lhr.aero. The Azure API Management catalogue returns an empty list (`{"value":[],"count":0}`) to unauthenticated callers.

## Access

- [How It Works — the access gate](https://developer.heathrow.com/how-it-works): Contact support@heathrow.com or 08443351801, state your user type and purpose, complete Heathrow's enrolment process, then sign in with Microsoft Active Directory.
- [Sign in](https://developer.heathrow.com/signin): "Sign in using your Azure Active Directory credentials."
- [Sign up](https://developer.heathrow.com/signup): No self-serve registration form is presented to anonymous visitors.
- Runtime gateway `https://api.heathrow.com` enforces mutual TLS — every anonymous request is rejected with "400 No required SSL certificate was sent".

## Docs

- [Developer portal](https://developer.heathrow.com/)
- [API list](https://developer.heathrow.com/apis) — renders empty to anonymous visitors
- [Products](https://developer.heathrow.com/products) — renders empty to anonymous visitors
- [API changelog](https://developer.heathrow.com/api-changelog) — page exists, zero entries published

## Artifacts (API Evangelist)

- [apis.yml](https://raw.githubusercontent.com/api-evangelist/heathrow-airport/refs/heads/main/apis.yml)
- [Authentication profile](https://raw.githubusercontent.com/api-evangelist/heathrow-airport/refs/heads/main/authentication/heathrow-airport-authentication.yml)
- [API conventions](https://raw.githubusercontent.com/api-evangelist/heathrow-airport/refs/heads/main/conventions/heathrow-airport-conventions.yml)
- [Conformance](https://raw.githubusercontent.com/api-evangelist/heathrow-airport/refs/heads/main/conformance/heathrow-airport-conformance.yml)
- [Lifecycle](https://raw.githubusercontent.com/api-evangelist/heathrow-airport/refs/heads/main/lifecycle/heathrow-airport-lifecycle.yml)
- [Changelog](https://raw.githubusercontent.com/api-evangelist/heathrow-airport/refs/heads/main/changelog/heathrow-airport-changelog.yml)
- [Packages / SDK search](https://raw.githubusercontent.com/api-evangelist/heathrow-airport/refs/heads/main/packages/heathrow-airport-packages.yml)
- [Well-known discovery probes](https://raw.githubusercontent.com/api-evangelist/heathrow-airport/refs/heads/main/well-known/heathrow-airport-well-known.yml)
- [Domain security](https://raw.githubusercontent.com/api-evangelist/heathrow-airport/refs/heads/main/security/heathrow-airport-domain-security.yml)
- [Review](https://raw.githubusercontent.com/api-evangelist/heathrow-airport/refs/heads/main/review.yml)

## Notes for agents

- There is no anonymous path to any Heathrow API operation. Do not attempt to construct request URLs — no base path is published, and the gateway rejects requests without a Heathrow-issued client certificate before routing.
- Heathrow sells no seats, holds no bookable inventory, issues no PNRs or e-tickets, and sits entirely outside the GDS and IATA NDC value chain. It is airport infrastructure, not a travel intermediary.
- For flight schedules, status and connection data covering LHR without an enrolment, commercial alternatives exist (OAG, Cirium, FlightAware AeroAPI). Airport weather by IATA code is a commodity available from many providers.
- heathrow.com's website terms prohibit systematic downloading of site content into a database (clause 5.5.2) and prohibit caching or mirroring for third parties (clause 5.3).
- Company: Heathrow Airport Limited, The Compass Centre, Nelson Road, Hounslow, Middlesex TW6 2GW. Portal footer credits LHR Airports Limited (England company number 1970855).