| What it does | A fast, private and offline API client for REST, gRPC, GraphQL and WebSocket services
| Test, debug, and evaluate MCP servers across every major AI client
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| Stage | Not given
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| Founded | Not given
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| Based in | Not given
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| Pricing model | Open source
| Freemium
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| Pricing | Not given
| Free: $0/mo with 200 credits/day and 500 free eval iterations. Pro: $24/mo (billed annually at $288/year) with 5,000 credits/mo. Team: $199/mo (billed annually at $2,388/year) with 50,000 credits/mo. Enterprise: Custom pricing. Additional credits: $10 per 1,000 credits (Pro), $9 per 1,000 credits (T
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| Key features | - REST and HTTP with every method, query and path params, JSON, XML, text, form-data, URL-encoded and binary bodies
- gRPC with server reflection or proto files, unary and server-streaming calls, metadata and trailers, TLS and mutual TLS
- GraphQL queries and variables with data and errors split out
- WebSocket text, JSON and binary messages with live message log
- Traffic proxy to capture HTTP(S) traffic of apps and phones
- Python scripting for pre and post-request scripts with tests
- Test cases and CI integration with chapar-cli
- Environments with variables and secret values encrypted with OS keychain
- Import Postman collections, OpenAPI specs and proto files
- Code generation for cURL, Python, Go, JavaScript, Java, Ruby and .NET
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| What makes it different | - Local-only data with no cloud sync or telemetry
- GPU-rendered native UI that starts quickly and runs on macOS, Linux and Windows without a browser engine
- Collections stored as YAML files in git for version control
- Built-in traffic proxy for inspecting and importing HTTP(S) traffic from other apps
- Free and open source under BSD 3-Clause license
| - Tests how external AI clients use your MCP server, not just how your code runs
- Open source core runs locally or in your own CI, never sees live traffic
- Evaluations score tool choice and goal completion across repeated runs, not brittle assertions
- Automatically maintains current behavior of 16+ AI clients so your tests stay relevant
- Framework and deployment agnostic: works with any MCP server however it was built
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| Free plan | Not given
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| Open source | Not given
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| Platforms | Not given
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| Public API | Not given
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| Community votes | 0 | 0 |
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| DR (Domain Rating by Ahrefs) | 6 ● no change since last check | 63 ▲ +1 (up) since last check |
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| Trust Flow (Majestic) | 5 | 20 |
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| Citation Flow (Majestic) | 26 | 42 |
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| Referring domains (Majestic) | 31 | 399 |
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Chapar
MCPJam