Free desktop app · v1.0.6
The Postman for AI, on your machine.
Test, compare, and optimize prompts across every model — side by side, with your own API keys. Free, desktop-first, no signup to start.
Auto-updates after install. On another OS? Use the web app →
Works with the models you already use — bring your own API keys
Run one prompt across every model — at once
Pick your models, write a prompt, hit Run, and see every model’s answer, latency, and cost side by side. Stop guessing which model is best; see it.
Bring your own keys. Keep them local.
Add the providers you already pay for — OpenAI, Anthropic, Google, OpenRouter, fal and more. Your keys are stored on your machine and used to call the providers directly.
Why the desktop app
Instant testing
Run a prompt against multiple models at once — no glue code, no dashboards to wire up.
Informed decisions
Compare outputs, latency, and cost directly. Pick the model that actually wins for your task.
Cost reduction
See where a cheaper model gives the same answer and switch — before it hits your bill.
Local & private
Your API keys stay on your machine. The app calls providers directly with your keys.
Save scenarios
Keep the prompts, inputs, and model sets you test often. Reopen and re-run in a click.
Graduate to production
When a prompt is ready, promote it to a versioned VernaOne endpoint with automatic fallback.
How it works
- Download & install for macOS or Windows — it’s free.
- Add your API keys for the providers you use. They stay on your machine.
- Write a prompt, pick the models to compare, and hit Run.
- Compare outputs, latency, and cost — and ship the winner.
Ready to ship it? Go model-agnostic.
When a prompt works, VernaOne turns it into a versioned endpoint that runs across every provider with automatic fallback and cost control.
Open the VernaOne web app →Frequently asked
What is the VernaOne desktop app?
A free desktop app — the "Postman for AI" — for testing and comparing LLM prompts across providers with your own API keys. Run one prompt against multiple models side by side, compare outputs and latency, save scenarios, and pick the best model for the job. It is desktop-first and works with OpenAI, Anthropic, Google, and more.
Is the desktop app free?
Yes, the desktop app is free to download and use with your own provider API keys. No signup required to start.
Which operating systems are supported?
macOS (Apple Silicon) and Windows 10/11 (64-bit). Download the installer for your platform below; the app auto-updates.
Do I need to share my API keys with VernaOne?
No. The desktop app stores your provider API keys locally and calls the providers with your keys — bring your own keys, keep them on your machine.
What is the difference between the desktop app and the VernaOne web platform?
The desktop app is the free "Postman for AI" for hands-on prompt testing and model comparison. The VernaOne web platform turns prompts into versioned, model-agnostic API endpoints with automatic fallback, cost analytics, and evals for production use.