Short answer: Use the existing client collections as evidence of the API and consolidate them into an OpenAPI contract. Then generate the request set from the spec. This is a one-time move that replaces a maintained client vault with a maintained, versioned contract.

What the collections already contain

Paths, methods, bodies, headers, and expected responses — a practical, partial description of the API. They are the fastest way to seed a contract without starting from a blank page.

The migration path

  1. Export the collections and convert the requests into operations.
  2. Add response schemas from real responses and validate the contract.
  3. Generate the request set and compare it to the old collection.
  4. Once aligned, make the spec the source and retire the vault.

What to expect

The first pass will miss responses and edge cases that the collections never captured. Close those gaps against the running API; the resulting contract is more complete than the collection.

The payoff

After the move, the request set is an output. The docs, mocks, and tools share the same source, and the team stops maintaining a separate client artifact.

This is part of the Powerduck vs Insomnia comparison. Next, read contract testing.