API Mocking & Stub Servers

In WireMock, withRequestBody(equalToJson(...)) parses the request body as JSON and requires it to equal your expected document exactly. Extra fields, missing fields and reordered arrays all make it miss. Two optional flags relax extra elements and array order.

WireMock renders a stub body only when the response-template transformer is attached to that response. Without it, WireMock treats the body as literal bytes and returns the Handlebars source unchanged. Attach it with withTransformers, or launch WireMock with --global-response-templating.

Put both WireMock stubs into one scenario with inScenario. The first requires the start state and calls willSetStateTo to move the conversation on. The second requires that new state and answers only once the first has served.

Negate the header name. MockServer holds request names and values as NottableString values, so a header built from not("X-Sweep-Tenant") matches only calls that carry no such header. Negating the value instead matches a header that is present but different.

Yes. MockServer matches on a subset, not on equality. Every header, cookie and query-string parameter you name is a constraint the request must satisfy; every one you do not name is ignored, however many the client sends.

WireMock's admin API at /__admin/mappings lists every registered stub on GET and registers one new stub from the posted body on POST. DELETE on the same path removes all of them. Any HTTP client can drive it while the server runs.

A hosted mock service is a stub server a vendor runs for you. Its canned replies live in an account on their platform, reachable at an address they control. What you give up is custody: review, rollback and availability.

The POST /imposters response is the created imposter, and its port field holds the number mountebank bound. Read it from that response, or list running imposters with GET /imposters, then build the worker's base URL from it.

Call resetRequests() on WireMock's WireMockServer, or resetAllRequests() from its static client DSL; over the admin API it is DELETE /__admin/requests. It resets the request journal alone, so stub mappings, scenario state and global settings all survive untouched.

Call DELETE /__admin/mappings/{id} with the id WireMock returned when the stub was registered. That removes exactly that mapping and leaves the rest in place, while DELETE on the collection path clears every registered mapping at once.

Mountebank's proxyOnce forwards the first matching glossary request to the real service and answers later identical ones from the saved reply. proxyAlways forwards every matching request upstream. proxyTransparent forwards everything and saves nothing, staying a pure pass-through.

Run WireMock standalone with --record-mappings and --proxy-all pointed at the kayak-rental base URL. Every request is forwarded upstream and the real reply is written back as a stub mapping. Large response bodies are extracted into separate body files.

In WireMock, startRecording puts the running server into recording mode against a target base URL. WireMock's stopRecording ends the session and returns a SnapshotRecordResult holding the stub mappings built from the traffic. Both are also WireMock admin routes.

It serves the public CA certificate WireMock signs browser-proxy certificates with. A client proxied through WireMock must install it in its trust store, or the call fails before any stub is matched. The private key stays on the server.

WireMock's --https-port opens an extra TLS listener on that port. --https-keystore points at a Java keystore holding the certificate WireMock presents there, and --keystore-password unlocks it. Omit both and WireMock serves its own bundled self-signed certificate instead.

MockServer keeps a journal of every request it receives, and MockServerClient.verify asserts against it. Pass a request definition describing the POST plus a VerificationTimes count. When nothing matches, verify throws an AssertionError listing the requests the journal did record.

WireMock's --no-request-journal flag stops the server recording the requests it receives. Because nothing is recorded, verification is not weakened but abolished: the disabled journal raises RequestJournalDisabledException. A verify() call after that flag can never pass, whatever the client sent.

With makeStubsPersistent set to false, WireMock keeps the regenerated stubs in memory only: they serve requests while the instance lives and vanish on restart. Its default, true, writes each one as a JSON file under the mappings directory.

VerificationTimes carries six factories: never, once, exactly, atLeast, atMost and between. Each turns a MockServer verification from at least one matching request into a precise count assertion, so a duplicated or missing hold request fails the test rather than passing.

MockServer reads the OpenAPI document, then creates one expectation for each operation it selects, matching that operation's method, path and declared parameters. Each expectation replies with the response the document declares. The entry point is upsert(OpenAPIExpectation...) on MockServerClient.