Plugins

Imposter uses plugins to control its behaviour and provide specialised mocks.

The following table describes the available plugins.

Category	Plugin name	Description	Details	Supported versions
Mock	grpc	gRPC mocks.	External plugin (5.x). See gRPC plugin.	5.x
Mock	hbase	HBase mocks.	See HBase plugin.	4.x
Mock	openapi	OpenAPI (and Swagger) mocks.	Built-in. See OpenAPI (and Swagger) plugin.	4.x, 5.x
Mock	rest	REST mocks.	Built-in. See REST plugin.	4.x, 5.x
Mock	sfdc	SFDC (Salesforce) mocks.	See SFDC (Salesforce) plugin.	4.x
Mock	soap	SOAP (and WSDL) mocks.	Built-in. See SOAP plugin.	4.x, 5.x
Mock	wiremock	WireMock mappings support.	See WireMock plugin.	4.x
Scripting	js-graal	Graal.js scripting.	Graal.js JavaScript scripting support. This is the default JavaScript script engine. See Modern JavaScript features.	4.x
Scripting	js-nashorn	Nashorn scripting.	This is the legacy JavaScript script engine	4.x
Store	store-dynamodb	DynamoDB store implementation.	See DynamoDB store.	4.x
Store	store-redis	Redis store implementation.	See Redis store.	4.x
Store	store-graphql	GraphQL store queries.	See GraphQL.	4.x
Configuration	config-detector	Detects plugins from *-config files.	Built-in	4.x
Configuration	meta-detector	Detects plugins from META-INF.	Built-in	4.x
Data generator	fake-data	Generates fake data.	See Fake data generator.	4.x, 5.x
Authentication	oidc-server	OpenID Connect authorization server.	External plugin (5.x). Provides a full OIDC authorization server for testing auth flows.	5.x
Documentation	swaggerui	Interactive Swagger UI viewer.	External plugin (5.x). Built-in (4.x). Serves an interactive UI for OpenAPI specifications at /_spec/.	4.x, 5.x
Documentation	wsdlweb	Interactive WSDL/SOAP viewer.	External plugin (5.x). Serves an interactive UI for WSDL files at /_wsdl/.	5.x

You can also write your own plugins, if you want to customise behaviour further.

Plugin loading

Imposter loads plugins from the plugin directory. This is configured using the following environment variable:

IMPOSTER_PLUGIN_DIR="/path/to/dir/containing/plugins"

Imposter 4.x

When you set the plugin directory environment variable in Imposter 4.x, plugin JAR files placed in this directory will be loaded by Imposter on startup.

Imposter 5.x

Imposter 5.x requires you to also set the IMPOSTER_EXTERNAL_PLUGINS environment variable:

IMPOSTER_EXTERNAL_PLUGINS=true
IMPOSTER_PLUGIN_DIR="/path/to/dir/containing/plugins"

See imposter-go for available plugins.

Using the CLI

If you are using the Imposter CLI, you can install a plugin with:

imposter plugin install -d <plugin name>

The CLI automatically manages the plugin directory, so you do not have to set the IMPOSTER_PLUGIN_DIR environment variable.

For example:

imposter plugin install -d stores-dynamodb

This will install the plugin version matching the current engine version used by the CLI. The next time you run imposter up, the plugin will be available.

Using the Docker image

If you are using the Docker image, you can bind-mount a local directory to the /opt/imposter/plugins directory within the container.

For example:

docker run --rm -it \
    -v /path/to/plugin/dir:/opt/imposter/plugins \
    -v /path/to/config/dir:/opt/imposter/config \
    -p 8080:8080 \
    outofcoffee/imposter

The Docker container sets the environment variable IMPOSTER_PLUGIN_DIR=/opt/imposter/plugins, so you do not have to set it explicitly.