A design document is a workspace containing tools to design an API specification. You can write and edit a spec, generate a collection from the spec to send requests, and create test suites to run different types of tests against your API or API spec.
For more details, see Documents
A request collection is a workspace for sending requests. You can create new requests or import requests from an API spec, clipboard, or even from a Postman collection. Requests can be customized with environment variables, template tags, pre-request and after-response scripts. Requests can be run individually or as a series of requests to run together.
For more details, see Collections
A mock server is a self-hosted or cloud-hosted way to simulate an API endpoint. You can create a mock server and define endpoints manually, or generate them from existing responses. You can customize the response code, body, and headers.
For more details, see Mock servers.
The Insomnia Scratch Pad is a local workspace that you can use to send requests. It doesn’t require creating an Insomnia account. The Scratch Pad functions as a collection, and you have access to all collection features.
For more details, see Scratch Pad.
The Collection Runner is a tool that allows you to send multiple requests in a specific order. You can also chain requests to reuse elements from a request or response in another one.
For more details, see Use the Collection Runner and Chain requests.
A template tag is a type of variable that you can use to reference or transform values. You can reuse an element from a request or a response, get the current timestamp, encode a value, prompt the user for an input value, etc.
A pre-request script is a feature in a collection that allows you to define actions to perform before running a request. For example, you can set a variable, add a query parameter, remove a header, etc. Once you send the request, the pre-request script runs before the request is actually sent. The results of the script are displayed in the console.
An after-response script is a feature in a collection that allows you to define actions to perform after receiving the response to a request. For example, you can get the response body, check for data types, clear a variable, etc. The results of the script are displayed in the console.