Master API Testing with Insomnia: A Lightweight Alternative to Postman

Insomnia Overview

Insomnia is an open‑source, cross‑platform API client that supports GraphQL, REST, WebSockets, and gRPC, and has earned

32K

stars on GitHub.

Installation

Download the installer from the official website (https://insomnia.rest/download) and run it; the process is straightforward.

Usage

We use Insomnia to debug the mall e‑commerce project, which is built with SpringBoot, Vue, and uni‑app, and is Docker‑containerized with a multi‑module microservice architecture. The project’s GitHub repository has over 60K stars.

Boot project: https://github.com/macrozheng/mall

Cloud project: https://github.com/macrozheng/mall-swarm

Video tutorials: https://www.macrozheng.com/video/

Steps:

Open Insomnia and create a new workspace.

Start the mall project and open its Swagger UI at

http://localhost:8080/swagger-ui/

.

Import the Swagger URL into Insomnia using the import button.

After import, the API collection appears in the workspace.

Set environment variables – use the default Swagger environment and clear the

base_path

variable.

Configure the

Authorization

header; remove it for endpoints that do not require authentication (e.g., login).

For authenticated endpoints, add an

api_key

variable with the token obtained from the login API.

With these settings, you can successfully test both public and protected APIs.

Additional Settings

You can adjust the font size via the settings button in the lower‑left corner, and choose from 18 built‑in themes to customize the appearance.

Conclusion

Insomnia offers a sleek interface and powerful features while remaining lightweight compared to Postman, making it an excellent choice when you need a simple, efficient tool for API testing.