Imposter

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Introduction

Mock server for REST APIs, OpenAPI (and Swagger) specifications, SOAP web services (and WSDL files), Salesforce and HBase APIs. - Run standalone mock servers in Docker, Kubernetes, AWS Lambda or on the JVM. - Embed mocks within your tests (JVM or Node.js) to remove external dependencies. - Script dynamic responses using JavaScript, Groovy or Java. - Capture data from requests, then store it or return a templated response. - Proxy an existing endpoint to replay its responses as a mock.

The latest GitHub release listed on 25 Oct 2026 was v4.7.0, published 2025-07-14.

Features

These items are quoted from public documentation fetched on 25 Oct 2026. Taken from the repository README section “Features”.

1. run standalone mocks in place of real: run standalone mocks in place of real systems
2. turn an OpenAPI/Swagger file or WSDL file into a mock API for dev or QA: turn an OpenAPI/Swagger file or WSDL file into a mock API for dev or QA (use it before the real API is built)
3. decouple your integration tests from the cloud/back-end systems and: decouple your integration tests from the cloud/back-end systems and take control of your dependencies
4. validate your API requests against an OpenAPI: validate your API requests against an OpenAPI specification
5. capture data to retrieve later, or use in templates to for conditional: capture data to retrieve later, or use in templates to for conditional responses
6. proxy an existing endpoint to replay its responses as a: proxy an existing endpoint to replay its responses as a mock
7. Provide mock responses using static files or customise behaviour based: Provide mock responses using static files or customise behaviour based on characteristics of the request.
8. Power users can control mock responses with JavaScript or Java/Groovy: Power users can control mock responses with JavaScript or Java/Groovy script engines.

Pros

Points stated in the public sources fetched on 25 Oct 2026:

1. Repository topics: The repository’s GitHub topics include api-mock, grpc, hbase, mock, mock-responses, mock-server, openapi, protobuf.

Cons

The pages fetched on 25 Oct 2026 do not publish a limitations list. That absence is not evidence that the tool has no drawbacks. Current issues are tracked at https://github.com/imposter-project/imposter/issues.

Usage and Links (Example)

The repository README includes this example (from “Example”):

$ curl -v -X PUT http://localhost:8080/users/alice

HTTP/1.1 201 Created
Content-Type: application/json

{ "userName": "alice" }

Resources:

• Imposter website
• GitHub repository
• GitHub release v4.7.0

Pricing

No public price was found on the pages fetched on 25 Oct 2026. This rewrite does not guess a number. Check the official website before treating the tool as free or paid.

Recommended for?

The fetched pages do not name a target audience. Decide fit from the official description and the feature list above.

Conclusion

Imposter is summarized by its public description as: “Scriptable, multipurpose mock server.”.

The latest GitHub release listed was v4.7.0, published 2025-07-14.

This page was rebuilt on 25 Oct 2026 from www.imposter.sh, github.com. It keeps only what those pages stated. Confirm the current product, license, and price on the official site before you adopt it.