CS-03 · Travel
Integrating a supplier API that had no documentation
The transferable point
Missing documentation is a scoping problem, not a blocker. Investigate first as a paid phase, then quote the build — quoting a fixed price against an unknown API is how integrations run three times over.
The situation
A supplier whose availability and pricing were being copied into the operator's system by hand, four hours a week, every week. The supplier had an API. The supplier did not have documentation for it, and the person who did had left.
The problem
Four hours a week is a quarter of a working day gone permanently, and hand-copied data is wrong at a predictable rate. The operator had been quoted for the integration twice before and both quotes assumed documentation existed.
What we found
The supplier's own booking site used the same API. That meant the complete behaviour was observable — every request, every response shape, every error condition — by working through the site and capturing the traffic.
What we could not observe was rate limiting and failure behaviour under load, so we assumed the worst case and designed for it rather than discovering it in production.
What we built
We captured and mapped every endpoint the booking site used, then built a fixture set from the recorded responses so the integration could be tested without hammering a supplier we had no agreement with.
The integration itself is queue-based. Requests are idempotent, failures retry with backoff, and anything that fails repeatedly lands in a dead-letter queue that a person can inspect and replay rather than disappearing. A daily reconciliation compares what we hold against what the supplier reports and flags differences instead of overwriting silently.
We also wrote the documentation the supplier did not have — endpoint by endpoint, field by field, including the three undocumented error codes we found. That document went to the client and, as a courtesy, to the supplier.
The result
The four hours a week of manual entry stopped. Availability is now current rather than up to seven days old, which had been causing occasional overselling. The reconciliation has caught two supplier-side pricing errors since launch that would previously have gone straight into a customer quote.
If a supplier is costing your team hours a week in copy-and-paste, that is usually a two to four week job.
Start a conversation
Tell us what the system has to do.
Describe the problem in a paragraph and we will tell you honestly whether we are the right people for it — and roughly what it costs before you spend anything.