SpecCanvas

Discover, Don't Guess

Turn a rough idea into a structured spec. See the first shape of your app. Give any AI agent reusable context — not throwaway prompts.

Open SpecCanvas Read the docs

Free to use. No credit card.

The Stack

Methodology Format Tool

Evolutionary Specification

INDEPENDENT

Discovery-first approach. Explore with AI, select the best, refine iteratively.

UI Spec + Data Spec

OPEN STANDARD

Self-describing format AI understands natively. No vendor lock-in.

SpecCanvas

TOOL

Visual editing, side-by-side comparison, auto diagrams. The 10x accelerator.

UI Spec works anywhere. SpecCanvas makes it faster.

See before you build

A prompt disappears after one chat. A spec stays — reusable, structured, readable by any AI agent.

Traditional approach

Describe → Implement → See

(and hope it's right)

With SpecCanvas

Describe → See → Implement

(when you know it's right)

AI-Powered

How It Works

From idea to validated spec in hours, not weeks

Iterate Until perfect

1

AI Writes the Spec

From idea, mockup, or existing code.

2

AI Generates HTML

Same spec, different AI visions.

3

Compare Side-by-Side

Rate and pick favorites.

4

Refine with AI

Pin what works, regenerate the rest.

5

Export to AI Agent

Hand the spec to any coding agent — it understands the full app from one file.

The output is an executable specification, not just HTML.

What is UI Spec?

An open format for AI-native specifications

dashboard.ui.spec

screens:
  dashboard:
    blocks:
      - id: header
      - id: content

Claude GPT Gemini

One structure, three visions.

UI Spec is a language. Write anywhere. Send to any AI.

Progressive Precision

Control how much freedom AI gets. Start broad, add detail where needed.

purpose: User dashboard

Claude

Explore

AI has full freedom. 4 wildly different results.

blocks:
  - id: avatar
    purpose: "User avatar with level badge"
  - id: streak
    purpose: "Streak counter with flame"
  - id: achievements
    purpose: "Grid of achievement badges"
  - id: quests
    purpose: "Quests with progress bars"

Claude

Intent

Blocks defined. Styling varies.

theme: "Light airy, soft shadows"
palette:
  accent: "Coral and mint"

blocks:
  - id: avatar
    columns: 4
    purpose: "XP ring pulses near level-up"
  - id: streak
    columns: 8
    purpose: "Sun icon, amber pulse if at risk"
  - id: achievements
    columns: 6
    purpose: "Pastel unlocked, dashed locked"
  - id: quests
    columns: 6
    purpose: "Click → expand, confetti burst"

Claude

Refined

Same layout, aligned styling.

Precision where you need it.

Freedom where you don't.

Start Exploring

What You Get

Compact knowledge layer for your app

UI Spec enables OPEN FORMAT

AI-Native Understanding

Self-describing format. AI reads it without instructions. No prompt engineering. Works with any model — today and tomorrow.

Structure Lock

Your spec holds the structure. AI fills in the style. Change the look without breaking the layout. Evolve without starting over.

Reusable AI Context

Write the spec once — use it in every AI session. New chat, different agent, new team member — the spec carries the full app context. No re-explaining.

SpecCanvas accelerates VISUAL EDITOR

Multi-AI Comparison

Generate from Claude, GPT, Gemini, DeepSeek. View side-by-side. Rate and pick favorites. All in one interface.

Visual Block Editing

Edit specs visually. Drag blocks, adjust columns. See structure as you build. No YAML wrestling required.

Auto Diagrams

ER diagrams from Data Spec. Screen flow visualization. Understand complex structures at a glance.

Pricing

Everything you need. Free.

Free Plan

Unlimited projects
Unlimited specs
All AI integrations
Local storage
No account required

$0

Why free?

You already pay for AI.

Most AI tools charge you twice: subscription for the tool, plus token fees for the AI.

SpecCanvas takes a different approach. You copy prompts to your own AI (ChatGPT, Claude, Gemini — whichever you already use), and paste results back.

No middleman. No extra fees. Your data never leaves your device.

Copy Prompt

Paste to Your AI

Copy Result

Paste Back

Four clicks. Zero fees. Total freedom.

See it in action

From Spec to Interface

Structure locked. Style guided. Details — AI's creative choice.

Claude

Figma

Gemini

GPT

Time to generate: 30 mins

Lines of spec: ~100

AI models compared: 4

Yes, even Figma AI reads UI Spec.

What you see is what you refine.

Explore this project in SpecCanvas →

Ready to discover?

Free tier. Open format. Your AI. Your rules.

Start Building