API Testing Tool Features
All-in-One API Testing & Development Tool
SchemaClient combines a REST API client, localhost tunneling tool, real-time API traffic monitor, webhook tester, and JSON schema validator into one free native desktop app. The best free Postman and ngrok alternative.
REST API Client & API Tester
Test REST APIs with full control over HTTP methods, headers, query parameters, and request body. Send API requests, inspect responses, debug HTTP errors, and check API endpoints. Supports JSON, form data, multipart uploads, and raw payloads.
- ✓ GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS
- ✓ Request history and response inspection
- ✓ Syntax-highlighted JSON response viewer
- ✓ Response timing, headers, and status codes
Localhost Tunnel — Free ngrok Alternative
Expose localhost to the internet with a public HTTPS URL. The best free ngrok alternative for webhook testing, API demos, mobile app development, and sharing local servers with teammates.
- ✓ Instant public HTTPS URLs
- ✓ WebSocket-based for low latency
- ✓ Custom subdomain per user
- ✓ Request/response forwarding with full headers
API Traffic Monitor & HTTP Debugger
Real-time API monitoring tool to watch every HTTP request and response flowing through your tunnel. Debug API calls, inspect headers, request/response bodies, timing, and status codes. Essential for webhook testing and API debugging.
- ✓ Live request/response streaming
- ✓ Filter by method, status, path
- ✓ Response time tracking
- ✓ Export logs for debugging
API Schema Validation & JSON Checker
Validate API responses against JSON schemas. Define expected response structures, catch API contract violations early, and ensure your REST APIs return exactly what your frontend expects. Built-in API response checker.
- ✓ Custom schema definitions
- ✓ Auto-validate responses
- ✓ Type checking and field validation
- ✓ Cloud-synced schemas
OpenAPI & Swagger Import Tool
Import OpenAPI 3.0 and Swagger 2.0 specifications to auto-generate API request collections. Convert your API documentation into testable requests instantly. Best API documentation import tool.
- ✓ OpenAPI 3.0 and Swagger 2.0
- ✓ Auto-generate requests from spec
- ✓ Organized folder structure
API Collections & Cloud Sync
Organize API requests into collections with folders and tags. Save API endpoints, sync API collections across devices, manage authentication (Bearer, Basic, API Key), and set base URLs. Like Postman collections but free.
- ✓ Organize with folders and tags
- ✓ Cloud sync across devices
- ✓ Auth inheritance (Bearer, Basic, API Key)
- ✓ Base URL and variable management