PostSync Pro

I'm building PostSync Pro, an open-source desktop tool in beta for API testing and QA automation. It imports Postman and OpenAPI definitions, maps coverage, and runs fuzz tests, mock servers and chained workflows.

View source

API workbench with request editing and analysis

My role: Creator and engineer
Work type: Independent product
Current state: Beta
Year: 2026

The product

PostSync Pro is a local-first API testing and synchronization toolkit built with Kotlin and Compose Desktop. The implemented workbench sends REST requests, manages encrypted named environments, saves redacted requests, runs bounded assertions, validates responses against OpenAPI and replays a redacted history.

The broader toolkit covers Postman/OpenAPI merge, specification validation, fuzz testing, mock servers, test chains, coverage maps and breaking-change detection. Screens that still use simulated data are explicitly presented as previews rather than production integrations.

Product capabilities

What works today.

API Workbench v2

Send REST requests, switch named environments, save redacted requests, run bounded declarative assertions and validate live responses against OpenAPI.
Postman & OpenAPI Sync

Merge older Postman collections with newer Swagger/OpenAPI specifications while preserving the testing context around the endpoints.
Safe Local Environments

Named environments support variable substitution and encrypted secret values; persisted requests and history are redacted before reaching disk.
SRS & Contract Validation

Compare API behaviour and definitions with requirements, validate live responses and surface contract mismatches without persisting raw secrets.
Fuzz Testing

Generate edge-case and security-oriented inputs including boundary values, injection-shaped payloads and negative scenarios.
Mock Server & Test Chains

Run local mock servers from specifications and connect sequential API calls through controlled variable passing.
Coverage & Breaking Changes

Map endpoint coverage, compare versions and expose untested methods or contract-breaking changes.
Honest Preview Boundaries

Scheduler, monitoring, external notifications and similar simulated screens are labelled as product previews until their integrations are implemented.

Toolchain

Kotlin
Compose Desktop
Ktor Client
Gemini / Groq / local GGUF
Local encrypted storage
Koin
Coroutines

PostSync Pro

What works today.

API Workbench v2

Postman & OpenAPI Sync

Safe Local Environments

SRS & Contract Validation

Fuzz Testing

Mock Server & Test Chains

Coverage & Breaking Changes

Honest Preview Boundaries