Insomnia vs Postman: What’s the Best Tool for API Testing in 2026?

We take a closer look at Insomnia—how it streamlines workflows, scales API testing, and puts AI-integrated tools to work in delivery environments today.

As software development continues to advance, the ability to efficiently test APIs across different platforms becomes crucial for enabling the robustness and reliability of applications.

API testing tools offer unique features and capabilities that streamline testing and development, and are now embracing AI. In this article, we compare Insomnia and Postman, with mentions of tools like SoapUI for specific enterprise scenarios—underscoring the significance of environment variables, API calls, AI integrations, and overall developer experience.

Choosing between Postman and Insomnia for a real project? Tool choice is rarely the main problem.¶

API testing decisions usually revolve around

• Pipeline integration: how tests are triggered across pipelines
• Failure ownership: how failures are triaged and owned
• Environment management: how environments are controlled
• Observability & reporting: how results are tracked and used in release decisions

What Is the Insomnia API Testing Tool?¶

Before comparing the tools, let’s start with the basics and answer some frequent questions about this topic.

What Is Insomnia in Testing?¶

Insomnia is an open-source desktop application for designing, debugging, and testing RESTful and GraphQL APIs. It supports API development by using API schemas to validate endpoints against their defined structures, improving workflows for developers and testers.

Its dynamic capabilities make it a valuable resource for handling dynamic API requests in real-time scenarios. With an easy-to-use interface, it simplifies the process of sending HTTP requests and analyzing responses, validating if APIs meet their design specifications. It requires no account for local use via its Scratch Pad, making it suitable for projects requiring minimal setup and enabling users to start testing immediately.

It provides native support for REST, GraphQL, gRPC, WebSocket, SOAP, and SSE, making it particularly well-suited for GraphQL and modern microservices, thanks to its native gRPC and WebSocket support. Insomnia also includes a dedicated API design feature for building and previewing OpenAPI specs. Teams can choose between local vault, Git Sync, or cloud storage, making it a local-first alternative to Postman's cloud-centric model.

Insomnia is developed by Kong, which acquired the project in October 2019 and continues to maintain it as an open-source tool alongside Kong's broader API management platform.

What Is Postman?¶

Postman is an API platform for designing, testing, and documenting RESTful APIs. It offers tools for sending HTTP requests, managing environments, and validating responses through an intuitive interface.

Its features include API schema support, automated testing with JavaScript, request chaining, collaboration tools, centralized workspaces with role-based access control, and support for REST, SOAP, and WebSocket protocols. It also includes Newman, Postman's CLI, for CI/CD test automation, along with mock servers and auto-generated, real-time API documentation. Sensitive values like API keys and tokens can also be stored as encrypted environment variables, secured with AES-256 encryption.

These make Postman effective for streamlining API development across individual and team workflows.

Is Insomnia The Same as Postman?¶

While Insomnia and Postman are both API clients used for designing, testing, and managing APIs, they are not the same.

Automated Testing¶

Each tool has unique features and user interfaces. Insomnia is known for its simplicity and streamlined interface, making it easy to create and execute API requests. Postman offers extensive documentation and collaboration features, along with comprehensive support for automated testing.

Postman's automated testing capabilities include scripting JavaScript-based tests and automating trials to validate responses and assert outcomes. One tradeoff worth noting: Postman's own community forum and support channels report that Postman can slow down as collections scale into the thousands of requests, particularly in the Collection Runner. The choice between Insomnia and Postman often comes down to personal preference and specific project requirements.

Other tools like SoapUI offer powerful automated testing features, including data-driven testing, assertions, and service mocking, making it suitable for enterprise-level validation and complex workflows.

Is Insomnia a Free API?¶

Insomnia is a free cross-platform desktop tool for designing and testing HTTP APIs. Its free Essentials plan includes Git Sync collaboration for up to 3 users, along with code generation, authentication wizards, and environment variables. This makes the free version well suited for solo developers and small teams working within that 3-user cap. The paid Pro plan removes that user cap for teams that need unlimited collaborators.

Is Postman a Free API?¶

Postman offers a free plan with core tools for API design, request building, and testing—but as of March 2026, the free plan is limited to a single user, with team collaboration requiring a paid plan. Paid plans unlock collaboration, monitoring, and more complex features like version control for enterprise workflows.

An Introduction to Comparing Insomnia vs Postman¶

When building quality software, understanding the API design and choosing the right cross-platform API client is pivotal. This analysis compares the main features of Insomnia and Postman, with occasional references to SoapUI for specific use cases—focusing on API and automated testing, as well as on developer productivity.

Postman offers extensive API documentation features, making it easier for teams to create, share, and maintain their API documentation.

The Postman team has developed a tool that’s widely used in the industry, but Insomnia offers a compelling alternative with features that promote efficiency and ease of use, especially for those looking to create organizations and manage their APIs in a streamlined environment.

While Postman is celebrated for its comprehensive feature set and user-friendly interface, SoapUI is often preferred for more complex SOAP-based services due to its robust testing features and ability to handle advanced API testing scenarios.

Comparatively, Insomnia shines with its minimalist design and effectiveness in handling both REST and GraphQL APIs, making it a favorite for developers who appreciate a streamlined workflow and powerful features without the complexity of SoapUI or the breadth of Postman’s features.

When to Consider SoapUI for API Testing¶

SoapUI allows detailed assertions and data-driven testing, which can be crucial for enterprise environments that require rigorous testing protocols. Additionally, it supports features like mock servers, enabling developers to simulate API responses during early stages of development.

If you want to read our full comparison of SoapUI vs Postman for API Testing, we invite you to read this article.

Would you like to explore more tools for API automation testing? We invite you to read this article: API Testing Tools: Best 15 In-Depth Reviewed

Hands-On with Insomnia: Our API Testing Approach¶

Let’s get to understand what features Insomnia has, why it’s often considered a go-to tool, and how it handles both REST and SOAP APIs. With this aim, we carried out these tests against the APIs GoREST CountryInfoService.

Following the style of the article “Hoppscotch: Open Source API Development Ecosystem”, we want to dive into how Insomnia behaves by testing a REST API versus Postman and a SOAP API versus SoapUI.

We will share some screenshots taken during the tests to show what the tool looks like. After downloading and installing it, its use is really intuitive since it presents an interface very similar to Postman.

Proof of Concept: GoREST¶

It is a web service that displays country information from a two-letter ISO code, for example, “UY”. It offers functions to recover the currency used, the language, the capital city, the continent, and the telephone code.

To get started, we created another project in the Insomnia dashboard. We also configured the environment and collections of the new Project:

Being able to manage environments is crucial. That’s why the first thing we did was configure the work environment. To do this, go to the environments menu and select the Manage Environments or Ctrl+E option:

In the environment manager, we display the options in Sub Environments and select Environment:

With the new environment created, we can click on the name to edit it and start writing the parameters in JSON format:

Once the environment is created, we must select it from the drop-down list:

Within the environment, create collections to organize and store the different requests:

Unlike Postman or SoapUI, collections or folders are not exported directly from the context menu. However, in Settings, you can move or copy them to another Workspace.

To import or export any document or collection from the workspace, go to the menu that is displayed in its name and select Import/Export:

As with similar robust tools, you can use parameters in requests through environment variables, defined in JSON format.

To invoke any parameter, press Ctrl+Space where you want to insert it, and it will display a list with all the available variables.

It is also possible to indicate the parameter directly in the Query section of the request:

In the case of sending a POST-type request, as in other tools, you can select the type of Body (JSON, XML, YAML, EDN, Plain, Binary File, No Body):

In the case of the API you are testing, it is necessary to send an authorization token. You can add it to the Auth section by selecting the type of authorization required:

Insomnia allows you to make requests from cURL. To do this, copy one of the cURLs offered by the GoRest API as an example and paste it into the request URL:

Likewise, it is possible to send attached files if you select Binary File in the Body:

After selecting the file, the request will look like this:

You can see the result on the right side of the screen as follows:

Another feature shared with other tools is the response history on the right to be able to trace our work:

Proof of Concept: CountryInfoService¶

It is a web service that displays country information from a two-letter ISO code, for example, “UY”. It offers functions to recover the currency used, the language, the capital city, the continent, and the telephone code.

To get started, we created another project in the Insomnia dashboard. We also configured the environment and collections of the new Project:

For requests of the SOAP type, select XML as the Body type and give it the corresponding format (XML):

An important thing: you must select the POST method, although it is possible to use GET in Soap web services, typically, given that this protocol uses verbose payloads, POST is usually used. In addition, it is also necessary to configure the headers:

And you get the answer:

If you prefer to pass data as parameters in the request, you can do it as follows:

Chaining API Requests¶

Insomnia allows the extraction of values ​​from the answers to be used in other requests. For example, using the response ID of a POST method in a GET request. You can see this Documentation for more information.

There are three types of response options:

Response – Body Attribute:¶

Works on JSON and XML responses, pulling attributes from a response body.

Response – Raw Body:¶

References the entire body contents of a request.

Response – Header:¶

Pulls specific header values out of a response.

For example, in the empty URL bar, enter ‘/response’ to specify the data you want to obtain, and the options will be displayed.

Select the desired one. In our case, we selected Body Attribute.

Then click on the red tag and configure the rest of the options.

In Request, specify which request you are referring to. Select it from the drop-down list. In Filter, which can be a JSONPath or XPath, enter the data that you want to obtain from the response, which will be displayed in the Live Preview box.

In the following example in the GoRest project, use the id obtained from the POST NewUser method response to send a GET UserById request. Pass the data as a request query:

And configure the tag as follows:

In the following example in the CountryInfoService project, take the ISO Code from the response of the CountryByName request and pass it to the FullCountryInfoByISOCode request as follows:

As in the previous case, we select the response that contains the data, and in Filter, we enter the corresponding XPath:

In this way, you can see that it is different from how data is handled between requests in Postman, for example, although Insomnia also allows you to do it through environment variables.

Testing With Insomnia¶

Unlike Postman or SoapUI, Insomnia API testing offers a separate tab for testing. Previously, we were working on the DEBUG tab with the requests and responses. Unit tests are based on the Mocha and Chai framework for assertions, with JavaScript, according to the documentation

You can organize unit tests in Suites, and run them individually. You also can run the complete Suite.

Image 1 shows the organization of unit tests in Suites in the left panel.

This second image shows the unit tests within the Suite, related to the corresponding request, in the central panel.

And image 3 shows the results of the tests with the time consumed, in the panel located to the right of the workspace.

In the case of the project with SOAP it is the same procedure:

Inso CLI¶

Inso CLI (Command Line Interface) for Insomnia is based on Node.js and the core Insomnia libraries. It allows you to use Insomnia functionality in terminal and CI/CD environments for automation. At this time, Inso CLI only works with design documents and does not request collections.

There are two ways to install Inso CLI:

• From an executable that is downloaded from GitHub Releases
• Through the official installer, downloading the platform-specific build (macOS, Windows, or Linux) from Inso CLI's installation docs.

Although Insomnia is primarily used for functional and integration testing, it can also support load testing when combined with external tools or scripts. By leveraging its CLI and scripting features, it’s possible to simulate multiple API requests to observe response times and identify potential bottlenecks under load.

Inso Run Test¶

In our case, we installed it using the first option. After installation, we tried with the commands as explained in the documentation, and this was the result of running the test suites of the GoREST project:

When running the inso run test command without specifying a document, we are prompted to select one from the list. After selecting the document or suite to test, we are asked to select the environment, as shown in the screenshot.

We did the same for the CountryInfoService project:

If a report type (dot, list, spec, min, and progress) is not specified, spec is used by default.

Inso Export Spec¶

This command extracts and exports the raw OpenAPI specification. The OpenAPI specification is the standard for documenting APIs. OpenAPI 3.x offers several improvements, such as a simpler structure for defining APIs and more reusable components to reduce duplication.

With the –output <path> option, the specification is saved to a file.

Export the specification loaded in the ‘DESIGN’ tab.

An OpenAPI document describes the public interface of the REST API and defines information such as name and description, the individual endpoints (paths), and how issuers are authenticated. One of the main benefits of using OpenAPI is for documentation; once you have an OpenAPI document that describes your API, it’s easy to generate reference documentation for it.

Inso Generate Config¶

This command generates a configuration from the API specification declared in DESIGN using openapi-2-kong. The command works similarly to generating a declarative configuration file or Kubernetes manifest from Insomnia. An example can be seen.

Insomnia allows you to create a preformatted DecK file when adding endpoints to the document, or you can take a document and generate a Kubernetes manifest.

Both options are also available in the Insomnia user interface.

Continuous Integration, Test Automation, and Collaboration¶

Insomnia shines in collaboration, offering features that enhance project management and team synchronization. Its enterprise plan includes enterprise SSO, making it a preferred choice for organizations prioritizing security and collaboration.

Another benefit of using Insomnia in collaborative environments is its built-in version control, which allows teams to track changes in API designs and configurations over time, improving transparency and rollback capabilities when needed.

Seamless Integration¶

Inso CLI is designed to run in a continuous integration (CI) environment, removing the need to interact with the tools through prompts and providing exit codes to pass or fail the CI workflow. An example can be seen here.

Collaboration¶

To work as a team and to be able to synchronize projects, it is necessary to register in the Insomnia web dashboard. The documentation explains how to work as a team and synchronize projects.

Once entered into the dashboard, you can manage the team and add members via email.

Once the work is synchronized, all team members can view the shared dashboard projects on Insomnia API testing desktop.

Our dashboard:

A collaborator’s dashboard:

Pros¶

• Its paid version is the cheapest compared to Postman or SoapUI (see Insomnia's pricing).
• It allows you to manage the Cookies of the responses and send them in the requests automatically when necessary.
• It allows integration with GitHub in a simple way.
• It allows the handling of variables and data in a simpler way than alternative tools.
• It allows you to generate code snippets for more than 12 different languages ​​from the requests.
• It also allows you to import an API swagger in the DESIGN tab from a yaml file or by manually entering the appropriate format.

Cons¶

• Environment variables can only be set in JSON format.
• The test scripts must be entered manually since it does not present snippets like Postman for example.
• Collaboration and teamwork are only available in the paid version.
• There’s Little documentation about requests for SOAP.
• Inso CLI does not work with collections.
• It’s only available for Desktop in English.
• Although it presents a dashboard on the web for teamwork management, requests and responses can only be managed from the desktop version.

AI Integrations in Insomnia and Postman¶

AI on Insomnia¶

Insomnia now ships AI-native features as a core part of the product, available even on its free Essentials plan—not as an Enterprise-only beta. These include AI-assisted test-suite scaffolding from an imported

• OpenAPI spec, and a dedicated MCP Client, which lets Insomnia validate and debug MCP servers directly, ahead of using them in an agentic workflow.
• AI Runner, the optional proxy that sits in front of any LLM endpoint for semantic caching and guardrails, remains available as well.

AI on Postman: From Postbot to AI-Native Capabilities¶

Postbot was Postman's original AI assistant, launched in 2023 to help generate tests, documentation, and suggestions from natural language prompts. As of Postman's January 2026 update, Postbot has been superseded by AI-native capabilities built directly into the platform, which can read, write, and reason across Postman assets and code.

The centerpiece is Agent Mode, which turns natural-language prompts into actions across the API lifecycle—sending requests, fixing errors, updating tests, and generating code, without switching tools. Postman also introduced an API Catalog (a live operational view of an organization's APIs, tests, and production status) and native MCP server support, so AI coding agents like Claude Desktop or Cursor can pull structured, executable context about a team's APIs.

Key Features of Agent Mode¶

Insomnia's AI features remain narrower in scope by comparison, focused on scaffolding and proxying rather than autonomous action across the API lifecycle—though both tools are moving quickly in this direction.

Final Thoughts – Insomnia vs Postman¶

In comparing Postman vs Insomnia, Insomnia emerges as a tool that presents many advantages in API testing and developer productivity. Whether you’re an experienced software engineer or new to the field, Insomnia offers a robust set of features designed to improve your workflow and testing capabilities.

Insomnia API testing stands out as a powerful tool in this domain, offering an array of features designed to streamline the API lifecycle and enhance test automation—ultimately helping teams deliver high-quality apis more efficiently.

Although Insomnia has an interface very similar to Postman, as the work area is divided into 3 ‘tabs’ where different topics are dealt with (DESIGN/DEBUG/TEST), it makes it a more organized tool to work with. For teams new to API testing, Insomnia presents a smooth learning curve, thanks to its intuitive layout and straightforward workflow, making it accessible without compromising on advanced capabilities.

The dashboard that it presents with the different workspace projects and other actions, such as creating the documentation, is also user-friendly and helps keep our projects organized.

It has very similar features to Postman, but not so to SoapUI. Compared to Postman, we found it to be a very versatile tool when working with data and variables. In the testing section, it would be better if some snippets were added to help.

Inso CLI allows an approach to test automation, allowing to run the suites, although, in our opinion, it would be better to be able to run the collections.

In terms of AI integration, Insomnia and Postman differ significantly: while both tools have moved quickly on AI, Postman's shift from Postbot to full Agent Mode gives it an edge in autonomous, cross-lifecycle actions, while Insomnia's AI stays more scoped to scaffolding and MCP validation.

As for AI-driven support, Insomnia’s capabilities are still limited compared to Postman, which currently offers a more comprehensive suite of tools to assist developers during the testing and documentation process. Finally, the integration with GitHub is a notable advantage, as collaborative work on the network is increasingly essential nowadays.