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clients > summary-reviews

REST API Client Support for Exploratory Testing Summary Reviews

Reviews of REST API Clients covering how well the tool supports Exploratory Testing.

Introduction to Exploratory Testing Support Reviews

There are so many REST Clients available I have tried to list all those that I have evaluated here, with a summary of the evaluation results. The evaluation criteria was 'how well does the tool support exploratory testing'. If you also use the REST API Client for 'Test Automation' then you will evaluate and rank these tools differently.

The main headings are listed in alphabetic order. To see a recommended grouping check the section below.

For Exploratory Testing I use Bruno. I evaluated the tools below to make sure I have alternative tools and know the limits of each tool.

Tools last evaluated in April 2025.

A list of Open Source API Clients is available at the Awesome API Clients Github list. Many of desktop tools listed are reviewed below.

Grouped Recommendations for Exploratory Testing

If you are evaluating a tool for Exploratory Testing then start with those listed in this section.

Recommended Lightweight Free Clients

  • Bruno review - good all-rounder, free for commercial use. Recommended usebruno.com
  • Milkman review - a little rough around the edges, but open source and free for commercial use Milkman on github
  • Kreya review - proxy can only be configured via environment variables but capable when configured Kreya
  • Yaak review - lacks scripting, free for commercial use if run from source. yaak.app

Recommended Heavyweight Free Clients

  • Insomnia - review - easy to use without logging in, login required for multiple collections Insomnia.rest
  • Postman - review - requires logging in, feature packed, UI takes time to learn GetPostman.com

All Evaluated Client Summaries

All recommended clients have longer reviews.

I added tools in here that I do not recommend, simply because they are available, if you search the web you will find them. If you do have good experiences with tools that I have not recommend then feel free to let us know.

Advanced Rest Client

Since there are so many other Open Source and free API clients, I do not recommend.

API Dash

API Dash on github

  • Free and open source desktop client - last release Nov 2023
  • Super Simple. Create collections, but I have no idea where they are saved.
  • Can generate cURL commands
  • No proxy support.
  • No Open API import support.
  • No environment variable support
  • Cannot see history of requests and responses
  • Cannot see the request sent
  • no scripting capabilities
  • no custom methods

Would not recommend given the availability of other tools. Does not seem to be under active development.

Bruno

  • Bruno is Open Source.
  • Free for commercial use.
  • Aids Exploratory Testing well with good Proxy support.
  • Free plan also allows scripting.
  • Paid plans for CI usage, data driven and automated assertions
  • Good cURL integration with both export and import capabilities.
  • Provides Open API import, and other import formats supported.
  • usebruno.com

Read our full review of Bruno

Cartero

I'm tempted to view Cartero more like a front end for creating cURL requests rather than a REST API Client. It seems to build cURL requests quite well.

  • Allows you to create single requests, which are stored in files.
  • Cannot see a way to set a proxy.
  • No concept of collections.
  • You can't copy requests, but you could 'save as' new file and then load it back.
  • No concept of environment variables.
  • It does allow adding headers and parameters but there is no auto complete.
  • It does allow exporting to cURL
  • Cartero

Kreya

Kreya would be much easy to recommend with simpler Proxy configuration. But it is easier to configure the proxy for Kreya than build Yaak from source.

  • A free forever plan and I think can be used in a commercial environment
  • Can import Open API files
  • Can use a proxy but only if set environment variables.
  • No script capabilities in the free version.
  • A templating feature is avaiable with some ability to script.
  • Faker is built in to generate random data
  • Can use custom methods.
  • Kreya

Read our full review of Kreya

HTTPIE

  • Free for commercial use
  • Requires a login for basic functionality like 'choosing where to save files'
  • Does not support HTTP Proxy
  • Does not support Open API import - but can import from Postman and Insomnia
  • Pretty UI
  • Login for experimental Generative AI features
  • cURL Support
  • Can use Custom Methods
  • No Scripting
  • No request and response history
  • Httpie

Requires Open API import and Proxy Support to be viable for supporting Exploratory Testing.

Read our full review of Httpie

HttpMaster - Windows Only

  • Completely free
  • Windows only.
  • Lots of features.
  • I found the UI Cluttered and hard to use.
  • Given the amount of competition available there are other tools I would choose.
  • HttpMaster.net

Httpyac

  • VS Code plugin tool
  • Write and Issue API requests from text file
  • Allows the creation of a literate HTTP testing spec
  • Scripting and Request Chaining capabilities
  • To get the proxy working I had to configure vs code preferences > settings to 'on' and not 'override'.
  • I have an example .http file in the thingifier repo: httpyac example
  • Httpyac

Insomnia

An easy to use client for adhoc exploratory testing using scratchpad mode. Login is required for multiple collections.

  • Can Import many formats of API definition, including Open API
  • A History of requests can be seen, but cannot be exported.
  • cURL is well support for import and generation.
  • Environment variables are supported in requests and headers.
  • Proxy is easy easily configured.
  • Requests can be organised into folders.
  • Scripting is available in the free version.
  • Custom Methods can be used.
  • Insomnia.rest

Read our full review of Insomnia

Katalon Studio

Based on my evaluation, I don't think Katalon Studio should be viewed as an Exploratory Testing tool. It seems to be aimed at test automation and should be evaluated in those terms.

  • Requires Login
  • Clumsy sign up process
  • Free version does not support Open APi 3 files fully
  • Slow to send requests
  • Recommend evaluating it as a Test Automation tool, not an Exploratory Testing tool.
  • Katalon Studio

Read our full review of Katalon

MilkMan

I installed milkman by downloading the nightly release zip files. A completely free and Open Source REST API Client with collection and Proxy support.

  • MilkMan is a JavaFX application and should run on windows, mac and linux.
  • Import Open API files from disk
  • Can not see the actual request sent
  • Json responses can be queried using JMESPath
  • Supports simple scripting using plugin
  • Can configure a proxy
  • All Headers are manually configured. Can add custom headers. Header names do have auto completion, header values do not
  • Not support custom methods
  • Collections are saved to the database.db in the application folder when the application exits. Exportable to Postman.
  • Environment variable support.
  • Milkman

Read our full review of Milkman

Paw - Mac Only

  • Paw is now called Rapid API
  • Free, not open source
  • Mac only tool
  • Simple to use HTTP API Client
  • paw.cloud

A good choice if you are on Mac. I used this a lot for Exploratory Testing when I was primarily Mac OS based.

Postman

  • Import many collection formats
  • Export postman formats
  • Easy to configure proxy
  • Simple variable support
  • Most features required for exploratory testing in free plan
  • Scripting available in free plan.
  • Will probably be the default client for most people.
  • Feature Cluttered UI that takes time to get used to.
  • Collections stored in cloud, limited sharing on free plan. Be careful what you make public.
  • GetPostman.com

Read our full review of Postman

Pororoca

  • I had huge problems with this application.
  • I could import an Open API collection, but then I could not make any requests.
  • Most of the time when I clicked on an imported request the UI would go blank.
  • When I finally did manage to click Send for a valid URL, the application shut down.
  • From what I saw, there was no way to set a proxy.
  • And it didn't look like a history of requests was maintained.
  • Pororoca

Perhaps I downloaded an unluckily buggy version but I can't recommend.

REST Client

Listed here but requires future evaluation. These are initial notes.

  • Rest Client seems to be very similar to Httpyac
  • Rest Client seems to support a subset of curl so it might be possible to write cURL directly into the editor.
  • Does not get updated very often, last commit (October 2024)
  • Seems like a very interesting tool. Evaluate at the same time as HttpYac
  • Rest Client

SoapUI

  • does not import Open API v3 files in JSON format without amending file
  • UI is a bit clunky,
  • takes time to get used to
  • no shared environment variables
  • cannot switch off product usage data sent to mixpanel.com
  • free and open source
  • can make basic requests
  • can work through a proxy
  • can create collections
  • can create adhoc load tests
  • can output the http log for a test session
  • no cURL support
  • SoapUI

Read our full review of SoapUI

Thunder Client VS Code extension

  • The licensing model makes it hard to evaluate.
  • A Paid license is required for basic functionality.
  • Hard to recommend given the free plan available in Bruno or Yaak
  • Evaluate if you want a VS Code based IDE with cheap commercial license
  • thunderclient.com

Yaak

  • This is a very capable basic client which can be used for exploratory testing quite easily.
  • Open Source API client which requires a paid license if pre-built binaries are used in a commercial organisation with more than two people.
  • $50 per year per user to be compliant with license. All features available for evaluation period.
  • Yaak is completely free for commercial use if run from source.
  • Does not support scripting, but does support Request Chaining to populate new requests with data from earlier responses.
  • Good cURL integration with both export and import capabilities.
  • Provided excellent Open API import, with other import formats supported.
  • To get the most out of Yaak for exploratory testing I found that I needed to configure it to use a Proxy because the Requests are not shown in the Client, only the responses.
  • Supports custom methods.
  • Yaak

Read our full review of Yaak

 

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