Now in alpha

Ship AI-generated apps
you can actually trust

Vassa is a verification kernel for AI-generated UI. It treats model output as untrusted input, verifies it, and exports safe apps to every platform.

Get started GitHub
How it works
One pipeline. One trust boundary.
Your AI generates UI. Vassa makes sure it's safe before anyone sees it.
01
Generate
Your AI generates a UI description as JSON. Any model works — GPT, Claude, Gemini, open-source. Vassa doesn't care who made it.
02
Verify
The kernel compiles it into a deterministic plan and runs 30+ verification rules: layout, accessibility, security, resource budgets. Typed receipts for every decision.
03
Ship
Export verified apps to HTML, SwiftUI, or native macOS — all from one plan. If it passed the kernel, it's safe to ship.
30+
Kernel rules
1600+
Tests passing
25
Component packs
21
Verified themes
11
MCP tools
Features
Built for trust, not trust-me
Every feature exists to close the gap between "the AI said it's fine" and "it actually is."
Verification kernel
30+ rules check layout, a11y, security, and resource budgets. Auto-repair for common issues. Typed receipts for every decision — not "it passed," but why it passed.
One plan, every platform
Export verified apps to standalone HTML, SwiftUI source, or native macOS .app bundles. Same verification, same output, every target.
25 component packs
Dashboards, forms, charts, commerce, social, gaming — 100+ components that expand creative space without expanding the trust surface.
AI agent native
MCP server with 11 tools. AI agents can build, verify, theme, and export apps through structured tool calls. Not a UI for humans — a tool for agents.
ActionGraph runtime
Verified app logic — state, actions, effects, guards. Exported apps aren't just visual; they're functional. No new Function(), no eval. Safe evaluators only.
Deterministic by design
Same input, same output. Every time. Debuggable, replayable, cacheable. The kernel doesn't guess — it computes.
Get started
Five commands to verified
Install the CLI. Verify a plan. Export an app. That's it.
Terminal 
# Install the CLI
cargo install vassa-cli

# Verify a plan from any AI model
vassa verify plan.json --json

# Export to a standalone HTML app
vassa export html plan.json -o app.html

# Export to SwiftUI source
vassa export swiftui plan.json -o MyApp.swift

# Or start with the React library
npm create vassa@latest my-app
Component packs
25 packs. 100+ components.
Every pack is schema-validated, accessibility-checked, and cost-modeled. Expand the creative space without expanding the trust surface.
admin auth charts commerce dashboard data editors essentials feedback forms gaming governance layout maps media mini mobile nav notifications overlays printing social studio voice
21 verified themes
All WCAG AA contrast validated.

Built by builders, for builders

Vassa is alpha software. The kernel is solid. The edges are rough. Install it, break it, tell us what's missing.

Install the CLI Star on GitHub