Core Building Blocks

These are the Mountebank-compatible primitives every Rift config is built from. This page explains what each one is; the reference pages under Mountebank Compatibility give the exact syntax and every option.

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Imposter

An imposter is a mock server bound to a port. It declares a protocol (http or https), an optional name, and a list of stubs. Create one by POSTing it to the admin API (default port 2525) or loading it from a config file at startup.

{ "port": 4545, "protocol": "http", "stubs": [ /* … */ ] }

One Rift process hosts many imposters, each on its own port. → Imposters

Stub

A stub is a single match-and-respond rule inside an imposter: a set of predicates and a list of responses. On each request, Rift evaluates stubs top-to-bottom and uses the first stub whose predicates all match. A stub with no predicates matches everything (a good catch-all/default, placed last).

Predicate

A predicate decides whether a stub applies to a request. Predicates match on request fields (method, path, query, headers, body) with operators like equals, deepEquals, contains, startsWith, endsWith, matches (regex), and exists, plus jsonpath/xpath selectors and the logical combinators and, or, not. Multiple predicates in one stub combine with implicit AND. → Predicates

Response

A response is what a matched stub returns. The three kinds:

• is — a static response (statusCode, headers, body). Supports request interpolation.
• proxy — forward to a real upstream and optionally record the reply for replay.
• inject / _rift.script — compute the response dynamically with a script.

A stub can list several responses; Rift cycles through them per request (round-robin), honoring each response’s repeat count. → Responses

Behavior

A behavior post-processes a response before it’s sent. Rift supports wait (latency), copy and lookup (pull request/CSV data into the response), decorate and shellTransform (transform the body), and repeat (response cycling). → Behaviors

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Once these click, the Rift Model adds state on top: making responses depend on what happened on previous requests.