Compare the Top API Testing Tools as of October 2025

What are API Testing Tools?

API testing software is used to test and validate the functionality, performance, security, and reliability of Application Programming Interfaces (APIs). These tools help ensure that APIs perform as expected under various conditions and meet the required business and technical requirements. Features typically include automated testing, request/response validation, load testing, security testing (e.g., for vulnerabilities and authentication), and performance testing. API testing software often supports integration with continuous integration/continuous deployment (CI/CD) pipelines to facilitate automated testing as part of the software development lifecycle. Compare and read user reviews of the best API Testing tools currently available using the table below. This list is updated regularly.

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    KrakenD

    KrakenD

    KrakenD

    KrakenD is a high-performance API Gateway optimized for resource efficiency, capable of managing 70,000 requests per second on a single instance. The stateless architecture allows for straightforward, linear scalability, eliminating the need for complex coordination or database maintenance. It supports various protocols and API specifications, with features like fine-grained access controls, data transformation, and caching. Unique to KrakenD is its ability to aggregate multiple API responses into one, streamlining client-side operations. Security-wise, KrakenD aligns with OWASP standards and doesn't store data, making compliance simpler. It offers a declarative configuration and integrates with third-party logging and metrics tools. With transparent pricing and an open-source option, KrakenD is a comprehensive API Gateway solution for organizations prioritizing performance and scalability.
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  • 2
    Tyk

    Tyk

    Tyk Technologies

    Tyk is a leading Open Source API Gateway and Management Platform, featuring an API gateway, analytics, developer portal and dashboard. We power billions of transactions for thousands of innovative organisations. By making our capabilities easily accessible to developers, we make it fast, simple and low-risk for big enterprises to manage their APIs, adopt microservices and adopt GraphQL. Whether self-managed, cloud or a hybrid, our unique architecture and capabilities enable large, complex, global organisations to quickly deliver highly secure, highly regulated API-first applications and products that span multiple clouds and geographies.
    Starting Price: $600/month
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    Ambassador

    Ambassador

    Ambassador Labs

    Ambassador Edge Stack is a Kubernetes-native API Gateway that delivers the scalability, security, and simplicity for some of the world's largest Kubernetes installations. Edge Stack makes securing microservices easy with a comprehensive set of security functionality, including automatic TLS, authentication, rate limiting, WAF integration, and fine-grained access control. The API Gateway contains a modern Kubernetes ingress controller that supports a broad range of protocols including gRPC and gRPC-Web, supports TLS termination, and provides traffic management controls for resource availability. Why use Ambassador Edge Stack API Gateway? - Accelerate Scalability: Manage high traffic volumes and distribute incoming requests across multiple backend services, ensuring reliable application performance. - Enhanced Security: Protect your APIs from unauthorized access and malicious attacks with robust security features. - Improve Productivity & Developer Experience
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    SyncTree

    SyncTree

    Ntuple

    SyncTree strives to be a "Super Connecting Platform" that can easily connect any services you want. With SyncTree, which consists of SyncTree STUDIO, a solution for building backend business logic with block coding, and Block Store, a platform for buying and selling pre-made backend function blocks like App Store, you can organically utilize data and connect services to achieve unlimited service expansion. Based on aPaaS, Block Store provides APIs from various services such as ChatGPT, DALLE, YouTube, etc. in the form of 'backend function blocks', which you can subscribe to and then combine as you want quickly in SyncTree STUDIO to build your business logic. SyncTree is for everyone, whether you're an individual or a business, and you can subscribe and use it according to your needs, from the free version to the PRO version.
    Starting Price: Free/1Month/3,000 Call
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    Treblle

    Treblle

    Treblle

    Treblle is a federated API Intelligence platform built for enterprises that need full visibility, control, and security over their APIs. With a single integration, Treblle provides real-time API Discovery, Observability, Analytics, Governance, Runtime Security, and Developer Portals. It supports on-prem and private cloud deployments to meet strict compliance and data privacy requirements. Treblle helps teams shift left by surfacing API issues early in development and ensuring consistency across environments. Its AI-powered Integration Assistant simplifies onboarding and reduces manual effort. Trusted by global enterprises and recognized over 15 times by Gartner, Treblle accelerates innovation while giving you complete control over your API landscape.
    Starting Price: $25 per month
  • 6
    Autostub

    Autostub

    Torry Harris Business Solutions

    AutoStub® is an essential tool to speed up API development. It can significantly reduce your build time by quickly designing, prototyping, documenting and testing APIs. AutoStub® creates a functional mock that allows developers to work with APIs before they are fully implemented. Available as a SaaS offering, for On-Premise deployments and in a hybrid model. Key Features Simulate ReST and SOAP services Input format - Swagger files for ReST, WSDL files for SOAP services Support for GET, POST, PUT, DELETE methods in ReST Create WSDL/Swagger 2.0 based mock services; generate dummy data for API testing Get an endpoint URL that can be used on a third party SOAP client tool Improves quality by facilitating functional testing Can handle multiple test scenarios together
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    Levo.ai

    Levo.ai

    Levo.ai

    Levo.ai gives enterprises unparalleled visibility into their APIs while continuously discovering and documenting internal, external and partner/third-party APIs. Enterprises can then see the risk from their apps and prioritize it based on the sensitive data flows, AuthN/AuthZ usage and several other criteria. Levo.ai then continuously security tests all apps and APIs to find vulnerabilities in the SDLC as early as possible.
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    Apigee

    Apigee

    Google

    The Cross-Cloud API Management Platform. Build and deliver modern applications faster with well-managed APIs. Quickly deliver mobile apps to be where your customers are. Build a bridge between legacy systems and modern applications. Easily deliver partner and third-party offerings to customers through APIs. Hide clunky UIs and processes behind a clean API facade. Create a unified customer experience for your brand by unlocking siloed systems. Gain full visibility into API traffic, developer behavior, and other systems operations. Measure KPIs and generate actionable intelligence to inform business decisions. Leverage machine learning to identify anomalies and apply corrective actions. API management tools provide businesses with critical knowledge about API traffic trends, top developers, and API response times. This enables them to attract developers, improve API performance, find issues, and make better business decisions.
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