How we're different.
Not a feature-by-feature duel with any specific competitor. Just what we do differently from the typical API client — and why we think those differences matter.
The short version
We think an API testing tool should be local-first, fully-featured for free, built for every protocol, and honest about where your data goes. The typical tool in this category is none of those things.
We built Rostyman because we wanted to work offline, own our data, not pay per-user-per-month to test a WebSocket connection, and not worry about a breach at a vendor we've never met leaking our API keys. If that resonates, you'll probably like us.
Where your data lives
Typical API client
On their cloud. Even if encrypted at rest, it's subject to their outage, their acquisition, their data-retention policy.
Rostyman
On your machine. A local SQLite file at a path you control. Back it up, version it, inspect it.
What it costs to use every protocol
Typical API client
Teams-plan required for gRPC, WebSocket, MQTT, SSE. $12/user/month minimum to test an internal streaming API.
Rostyman
Free. Every protocol. Forever. Including MCP for AI agents — a capability that doesn’t exist in most alternatives.
Where your scripts run
Typical API client
On their servers. Your script receives your API credentials, executes remotely, returns results. Add network dependency + privacy surface.
Rostyman
In a local sandbox on your machine. Same API (rm.*), instant execution, zero cloud exposure.
How your API keys are stored
Typical API client
Alongside the collection as environment variables. Synced to their cloud by default.
Rostyman
In a separate encrypted vault. Never synced. Referenced by name in collections, so exports stay clean.
Account requirement
Typical API client
Required to install. Required to save. Required to share.
Rostyman
Optional, always. Download, double-click, work. The app never prompts for a login unless you opt into cloud sync.
Offline support
Typical API client
Degraded — some features require the cloud to function at all.
Rostyman
Full-feature offline. Airport, plane, disconnected lab — everything keeps working.
Customization
Typical API client
Two themes, five languages, one layout.
Rostyman
20+ themes (plus custom builder), 18 languages with RTL, configurable shortcuts, plugins.
Testing breadth
Typical API client
API testing only. Need a database? Open another app. Need to test the UI? Open a third.
Rostyman
API testing today. Database client and browser test runner coming soon — all in the same window, with linked context between them.
Export format
Typical API client
Proprietary JSON you can't read without the tool.
Rostyman
Plain human-readable .rostyman JSON. Diff in Git, grep it, open in VS Code.
AI integration
Typical API client
Chat sidebar that calls their LLM. One model. One provider.
Rostyman
Claude, OpenAI, or local Ollama — your pick. Plus full MCP server + client so AI agents get real tools, not just chat.
Where we're still catching up
We're in beta. Some things the mature tools do better today:
- No public collection marketplace yet — you bring your own.
- CI integrations are thinner than the established CLIs have had a decade to build.
- Real-time team collaboration (shared workspaces, live editing) is on the roadmap, not shipped.
- Documentation has gaps — we're writing as fast as we're shipping.
If those are make-or-break for you right now, stay on your current tool and come back in six months. If the trade-offs we've named are worth it, you'll like what's here today.