Imposter

Spec sheet

Purpose

Imposter runs interactive mock systems for development and QA, including before a real API is available.Read 4 Oct 2026 · imposter.sh

Intended users

The maker describes Imposter as a tool for developers and QA, including teams that want to decouple integration tests from cloud or backend systems.Read 4 Oct 2026 · docs.imposter.sh

Audience

The maker presents Imposter for developers, including API developers, and highlights development and QA use cases.Read 3 Oct 2026 · imposter.sh

Integrations

The CLI documentation describes embedding Imposter in JVM and Node.js tests, and using GitHub Actions or other CI/CD platforms including GitLab, CircleCI, Jenkins, Azure Pipelines, and Bitbucket.Read 4 Oct 2026 · docs.imposter.sh

Security

Imposter supports HTTPS through TLS configuration and can authenticate incoming HTTP requests using configured request conditions such as header values.Read 4 Oct 2026 · docs.imposter.sh

Maker

The linked Gatehill site identifies Pete Cornish as the person who builds tools under the Gatehill name.Read 4 Oct 2026 · gatehill.io

API validation and proxying

It can validate requests against an OpenAPI specification and proxy an existing endpoint to replay its responses as a mock.Read 4 Oct 2026 · docs.imposter.sh

CI/CD

The getting started guide describes using Imposter in GitHub Actions and other CI/CD platforms, including GitLab CI, CircleCI, Jenkins, and Azure Pipelines.Read 3 Oct 2026 · docs.imposter.sh

Data capture and proxying

Imposter can capture request data for later retrieval or templated responses, and proxy an existing endpoint to replay its responses as a mock.Read 3 Oct 2026 · docs.imposter.sh

Distribution limit

The Docker documentation says the core image includes OpenAPI, REST, and SOAP plugins, while the all image contains all plugins and has the most dependencies.Read 4 Oct 2026 · docs.imposter.sh

Dynamic responses

Responses can use static files or be scripted with JavaScript, Groovy, or Java; advanced users can write plugins in JVM languages.Read 4 Oct 2026 · docs.imposter.sh

Platform support

The CLI install page says its shell-script installation is for macOS and Linux; the CLI also supports native binary and Docker engines.Read 4 Oct 2026 · docs.imposter.sh

Pricing

The opened maker pages describe the project and its downloads but do not state a price or subscription plan.Read 3 Oct 2026 · imposter.sh

Request data

Imposter can capture request data for later retrieval or use it in templates to create conditional responses.Read 4 Oct 2026 · docs.imposter.sh

Request validation

The OpenAPI plugin can validate incoming request parameters, headers, and bodies against the specification.Read 3 Oct 2026 · docs.imposter.sh

Run modes

Imposter can run as a standalone server in Docker, Kubernetes, AWS Lambda, or on the JVM, or be embedded in JVM and Node.js tests.Read 3 Oct 2026 · docs.imposter.sh

Supported APIs

The documentation lists mock support for REST, OpenAPI/Swagger, SOAP/WSDL, HBase, Salesforce, and WireMock mappings.Read 3 Oct 2026 · docs.imposter.sh

Supported mocks

It supports REST, OpenAPI/Swagger, SOAP/WSDL, HBase, Salesforce, and WireMock mappings.Read 4 Oct 2026 · docs.imposter.sh

Telemetry

The feature documentation lists metrics collection and persistent or semi-persistent stores as configurable features.Read 3 Oct 2026 · docs.imposter.sh

Ways to run

You can run standalone mocks in Docker, Kubernetes, AWS Lambda, or on the JVM, or embed them in JVM and Node.js tests.Read 4 Oct 2026 · docs.imposter.sh

Where Specifiction places it

• API Mocking Tools#15 of 267.6