Best MCP Testing Toolsin 2026 — Reviewed.

Postman is the most widely-used API client globally, with support for sending requests and running JavaScript-based tests. While Postman doesn't have native MCP support, teams can manually test MCP endpoints by crafting JSON-RPC requests and validating responses with scripts. Postman's collection-based testing works for basic MCP validation, but requires significant manual setup for each tool call, prompt, and resource endpoint. MCP testing in Postman is script-heavy and disconnected from any specification or documentation. For teams already invested in Postman, it's possible to test MCP servers, but specialized tools offer significantly better workflows.

Bruno is an open-source API client that stores requests as markdown files in Git repositories. While Bruno supports REST and GraphQL, it doesn't have native MCP support. Teams can manually create MCP requests as JSON-RPC calls and store them in Git for version control. Bruno's offline-first, file-based approach is attractive for privacy-focused teams, but MCP testing requires manual setup and lacks validation, auto-generation, or integration with MCP specifications. Bruno is early in development and lacks the maturity for complex MCP testing workflows.

Insomnia (by Kong) is a popular open-source API client that natively supports REST and GraphQL. While Insomnia doesn't have MCP support, developers can manually craft JSON-RPC requests to test MCP servers. Insomnia's clean interface and plugin system allow for basic MCP testing, but there's no MCP-specific functionality, schema validation, or automation. Teams must manually maintain MCP tests and keep them in sync with server implementations. Insomnia is best for individual developers working with REST and GraphQL who occasionally need to test MCP endpoints.

AccelQ is an AI-powered test automation platform designed for enterprise continuous testing. It offers codeless test automation, AI-driven test generation, and comprehensive testing across API, web, mobile, and desktop applications. While AccelQ doesn't have native MCP support, its flexible automation framework can be extended to test MCP servers through custom code actions. However, this requires significant setup and doesn't provide MCP-specific validation or schema checking. AccelQ is best for enterprises needing broad test automation across multiple channels, not specifically for MCP testing.

ReadyAPI (formerly SoapUI Pro) is SmartBear's enterprise API testing platform supporting REST, SOAP, GraphQL, and other protocols. It offers functional testing, security testing, load testing, and data-driven testing with advanced reporting. While ReadyAPI can test any HTTP-based API, it lacks native MCP support. Teams can create custom test cases for MCP JSON-RPC endpoints using ReadyAPI's Groovy scripting, but this requires significant manual effort and doesn't provide MCP-specific validation. ReadyAPI is powerful for enterprise API testing but has an outdated UI and high pricing, making it less suitable for modern MCP-focused workflows.

SOAtest by Parasoft is an enterprise-grade API and service testing platform designed for complex enterprise environments. It supports REST, SOAP, messaging protocols, and offers comprehensive test automation with compliance-driven reporting. Like other enterprise tools, SOAtest doesn't have native MCP support but can be extended through custom scripting to test MCP servers. Its strength lies in regulated industries requiring audit trails and compliance reporting. However, SOAtest's focus on traditional enterprise SOA architectures and lack of MCP-specific features make it a poor fit for teams building modern AI applications with Model Context Protocol.