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Best API testing tools in 2026

These are the API testing tools in the CheckOps directory that most directly match the API-testing category. The shortlist is taken from tagged entries, not from a paid ranking. The directory has 105 tagged entries in this area; this page lists 15.

How we picked

CheckOps is a genuine and free directory. There are no paid sponsors, featured listings, or paid placement on these pages. The shortlist is built from tools already in the directory whose tags match the topic, with a preference for entries that have a fuller CheckOps page so the facts in the table can be checked against the source essay. This is not a claim that one tool is objectively better than another, and it is not a paid ranking.

Well-known tools that already have a CheckOps page in this area are listed first. The rest of the shortlist is filled from other tagged entries, preferring fuller essays so the facts in the table can be checked. That order is a way to keep the page useful, not a quality score and not a paid ranking.

Tools

  1. P

    1. Postman

    Go faster from development to production with higher accuracy and fewer tokens.

    Read the CheckOps page · Commercial, with a free or trial tier tagged

  2. I

    2. Insomnia

    The open-source, cross-platform API client for GraphQL, REST, WebSockets, SSE and gRPC.

    Read the CheckOps page · Open source

  3. S

    3. SoapUI

    SoapUI is a free and open source cross-platform functional testing solution for APIs and web services.

    Read the CheckOps page · Open source

  4. B

    4. Bruno

    Opensource IDE For Exploring and Testing API's (lightweight alternative to Postman/Insomnia).

    Read the CheckOps page · Open source

  5. H

    5. Hoppscotch

    Open-Source API Development Ecosystem • https://hoppscotch.io • Offline, On-Prem & Cloud • Web, Desktop & CLI • Open-Source Alternative to Postman, Insomnia.

    Read the CheckOps page · Open source

  6. K

    6. Karate

    Test Automation Made Simple.

    Read the CheckOps page · Open source

  7. R

    7. Rest-Assured

    Java DSL for easy testing of REST services.

    Read the CheckOps page · Open source

  8. P

    8. Pact

    Fast, easy and reliable testing for integrating web apps, APIs and microservices.

    Read the CheckOps page · Open source

  9. R

    9. RestSharp

    Simple REST and HTTP API Client for .NET.

    Read the CheckOps page · Open source

  10. P

    10. PactFlow

    Fast, easy, and reliable testing for your APIs and microservices at scale.

    Read the CheckOps page · Commercial

  11. X

    11. Xplorer

    Xplorer by Karate Labs is a local-first API workbench that opens OpenAPI specs and Postman collections, runs requests with no sign-in and exports them to Karate feature files.

    Read the CheckOps page · Commercial, with a free or trial tier tagged

  12. O

    12. oasdiff

    oasdiff is an Apache-2.0 command-line tool that compares OpenAPI specs to produce changelogs and detect breaking changes, with a GitHub Action and a hosted pull-request review workflow.

    Read the CheckOps page · Open source

  13. H

    13. Hurl

    Hurl is an Apache-2.0 command-line tool, written in Rust on libcurl, that runs and tests HTTP requests defined in plain text files, with captures, assertions and JUnit, TAP, HTML and JSON reports.

    Read the CheckOps page · Open source

  14. S

    14. Spectral

    Spectral is an Apache-2.0 JSON and YAML linter from Stoplight with ready-made rulesets for OpenAPI, AsyncAPI and Arazzo, used to enforce API style guides in editors and CI.

    Read the CheckOps page · Open source

  15. S

    15. Scalar

    Scalar is an MIT-licensed open-source API platform built around OpenAPI: an interactive API reference with generated code examples, an offline-first API client and hosted docs, now positioned as infrastructure for APIs in the age of agents.

    Read the CheckOps page · Open source, with commercial options tagged

Comparison

License, pricing model, and languages or platforms are taken from tags on each CheckOps page. Pricing notes are a short excerpt from that page's Pricing section when one exists. A blank or "not stated" cell means the CheckOps page does not record it.

Comparison of Best API testing tools in 2026
ToolLicensePricing modelLanguages / platformsPricing notes
PostmanCommercial, with a free or trial tier taggedFree tier, Paid, SaaSNot stated in the tags on the CheckOps pagePostman offers a variety of pricing plans to cater to different user needs: Free Plan: Includes core features, limited collaboration, and basic monitoring capabilities.
InsomniaOpen sourceFree, Open sourceNot stated in the tags on the CheckOps pageInsomnia offers different pricing tiers to accommodate various needs: Free Version: The open-source version of Insomnia is free to use, providing access to core features suitable for individual developers and small…
SoapUIOpen sourceFree, Open source, Free tierNot stated in the tags on the CheckOps pageSoapUI offers both a free version and a Pro version (SoapUI Pro), known as ReadyAPI, which includes additional features and advanced capabilities: SoapUI Open Source: Free to use and includes core features for basic…
BrunoOpen sourceFree, Open sourceNot stated in the tags on the CheckOps pageBruno is an open-source tool, which means it is free to use. There are no licensing fees or subscription costs associated with using Bruno, making it an excellent option for organizations looking for a cost-effective…
HoppscotchOpen sourceFree, Open sourceNot stated in the tags on the CheckOps pageNot stated in a Pricing section.
KarateOpen sourceFree, Open sourceNot stated in the tags on the CheckOps pageKarate is an open-source tool released under the MIT license, which means it is free to use for both commercial and non-commercial purposes.
Rest-AssuredOpen sourceFree, Open sourceNot stated in the tags on the CheckOps pageRest Assured is an open-source library and is available for free. There are no licensing fees or subscription costs associated with its use.
PactOpen sourceFree, Open sourceJava, Ruby, Node, Dot Net, Golang, Scala, Kotlin, Php, Javascript 2PactFlow offers several pricing tiers, including a free tier that’s ideal for small teams getting started with contract testing.
RestSharpOpen sourceFree, Open sourceDot NetRestSharp is an open-source library, which means it’s available for free to developers and organizations.
PactFlowCommercialPaid, SaaSPolygot, Java, Node, Golang, Dot Net, Scala, Kotlin, Ruby, Javascript, PhpPactFlow offers both free and paid subscription plans. The free tier is suitable for small teams or organizations exploring contract testing.
XplorerCommercial, with a free or trial tier taggedFree tier, PaidNot stated in the tags on the CheckOps pageXplorer's core is $0, including the Postman rail and Export to Karate; Premium features such as Try It with schema checks are paid.
oasdiffOpen sourceFree, Open sourceGolangoasdiff is free and open source under the Apache-2.0 licence.
HurlOpen sourceFree, Open sourceRustHurl is free and open source under the Apache-2.0 licence.
SpectralOpen sourceFree, Open sourceJavascriptSpectral is free and open source under the Apache-2.0 licence.
ScalarOpen source, with commercial options taggedOpen source, Free tier, PaidTypescriptScalar's open-source packages are free (MIT). Managed hosting has a free tier (publish references on an apidocumentation.com subdomain with SSL) and paid plans for teams.

FAQ

How did CheckOps pick these tools?
CheckOps is a genuine and free directory. There are no paid sponsors, featured listings, or paid placement on these pages. The shortlist is built from tools already in the directory whose tags match the topic, with a preference for entries that have a fuller CheckOps page so the facts in the table can be checked against the source essay. This is not a claim that one tool is objectively better than another, and it is not a paid ranking.
Does CheckOps sell placement on this list?
No. CheckOps does not sell featured or paid placement, and this page does not include sponsored listings.
How many api tools are in the directory?
This shortlist has 15 tools. The directory has 105 tagged entries in this area. See the API & contract testing stage for the wider set.
Are the one-line summaries complete reviews?
No. Each line is taken from the tool's CheckOps page (the short description, or the opening of the essay when that description is empty). Open the linked page for the full write-up.