Testnizer
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Everything in one app. Everything on-device.

Testnizer covers the full enterprise API surface — REST, SOAP, gRPC, GraphQL, WebSocket, SSE, plus an AI client and a workbench of cryptographic tools. None of it phones home.

Protocols

All seven protocols, first-class.

HTTP / REST

  • Full method coverage including TRACE and CONNECT
  • Body modes: raw / JSON / XML / urlencoded / form-data with file upload / binary
  • mTLS with project-scoped client certificates and OS-keychain-encrypted passphrases
  • HTTP / SOCKS proxy with auth, follow / no-follow redirects, custom timeouts
  • Pre-request and post-response scripts with a Postman-compatible pm API
  • Test assertions on status, headers, body, response time, JSON path, XML path
  • Cookie jar per workspace with manual edit

SOAP / WSDL

  • WSDL import from URL or file, SOAP 1.1 + 1.2 dual bindings
  • Multi-service, multi-port WSDL parsing with operation extraction
  • Manual envelope mode for hand-written SOAP / XML payloads
  • Automatic example envelope generation from XSD schema
  • WS-Security: UsernameToken (Text + Digest with nonce/created), Timestamp with TTL
  • XML Signature (RSA-SHA1 / RSA-SHA256), envelope or specific elements
  • XML Encryption (AES-128/256-CBC, AES-128/256-GCM, RSA-OAEP key wrapping)
  • SOAPAction extraction and header negotiation

WebSocket

  • ws + wss with custom headers and subprotocol negotiation
  • JSON / text composer with template variable substitution
  • Message timeline (sent + received) with timestamps and direction
  • Reconnection control with manual disconnect

GraphQL

  • Query, mutation, and subscription support over HTTP and WebSocket transports
  • Schema introspection with searchable type browser
  • Variables JSON editor synced with the operation
  • graphql-ws for live subscriptions, no SaaS proxy

gRPC

  • .proto file import via @grpc/proto-loader
  • All four streaming modes: unary, server-streaming, client-streaming, bidirectional
  • Metadata editor (request and response)
  • JSON skeleton automatically generated from message field types
  • TLS / mTLS with project-scoped certificates

Server-Sent Events

  • Long-lived event streams with automatic Last-Event-ID resume
  • Per-event filtering, JSON parsing of data payloads
  • Reconnect-with-backoff (configurable)

AI Chat

  • 14 providers: OpenAI, Anthropic, Google, xAI, DeepSeek, Mistral, Groq, Perplexity, Cerebras, Cohere, Fireworks, DeepInfra, Together, OpenRouter
  • Custom URL provider for self-hosted vLLM / LM Studio / Ollama / TGI endpoints
  • Streaming responses with abort support
  • Multi-turn conversations with system prompt control
  • Environment variable resolution in URL, headers, and body

Built-in tools

No more pasting tokens into jwt.io.

These all run inside Testnizer's main process, with no network call. If your machine is offline, they still work.

JWT debugger

Decode header and claims, verify HS / RS / ES signatures, inspect against expected issuer / audience. Token never leaves the process.

WS-Security workbench

Apply, verify, decrypt, and sign arbitrary XML. Same engine as the SOAP request panel. Useful for inspecting captured envelopes.

AES / RSA encrypt / decrypt

Standalone tool for opening encrypted XML payloads without uploading them anywhere.

JSON / XML formatters

Pretty-print, minify, and validate. Multi-line input, syntax errors with line numbers.

Encoders / decoders

Base64, URL, Hex, HTML entities, Unicode escape — paired text fields, instant convert.

JSONPath / XPath / XSLT / Jolt

Evaluate expressions against an in-editor sample, see matches highlighted, save common queries.

Text diff

Side-by-side, line / word / char granularity, ignore whitespace toggle.

Certificate manager

Local cert store, mTLS / client certificates per project, OS keychain encryption for passphrases.

Workflow

The collaborative bits, without a cloud.

Collection runner

Sequential or parallel execution of multiple endpoints with HTML report output. Iterate over data files for parameterised runs.

Test suites

Multi-collection regression sets with auto-detected import (Testnizer + Postman + Insomnia formats).

Scheduler

Local cron-style scheduling for repeat runs against staging or QA endpoints. No background SaaS workers.

Git integration

Project files commit through your existing repo. Branch with the project, review through PRs.

Console

Virtualised log timeline with per-tab filtering, raw request / response capture, search.

Code generation

Export any request as cURL, JavaScript fetch, Python requests — useful for sharing without sharing tokens.

Try it in five minutes.

Free. MIT-licensed. No account, no waitlist, no telemetry.

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