Stagewise – Open Source Agentic IDE for Frontend Development

TL;DR

TL;DR: Stagewise is an open-source, browser-based agentic IDE that runs a coding agent with full access to your tab’s console and debugger — reverse-engineer any site, make temporary test changes, or connect a codebase for permanent edits.

Source and Accuracy Notes

⚠️ This section is MANDATORY. All links must be verified from actual source, not guessed.

• Project page: stagewise.io ← verified by direct visit
• Source repository: github.com/stagewise-io/stagewise ← README read end-to-end
• License: AGPL-3.0 ← verified via GitHub API
• HN launch thread: news.ycombinator.com/item?id=44798553 ← Show HN, 46 points
• Source last checked: 2026-07-20 (commit main, 6,737 stars)

What Is Stagewise?

Stagewise is an open-source agentic IDE — a browser-based development environment where an AI coding agent runs directly inside your tab. Unlike a chat-only Copilot interface, Stagewise gives the agent full access to your browser’s console and debugger, enabling it to inspect live state, read network requests, and make changes you can verify immediately.

The core promise: no context switching between “ask the AI” and “see what it did.” The agent works where you work — inside the browser tab.

Key capabilities

From the official README:

• Browse and build in the same tool — no tab switching between browser and editor
• Full console and debugger access — the agent reads live DOM state and errors
• Temporary test changes — experiment without committing
• Connect a codebase — permanent, production-ready edits
• Reverse-engineer any website’s components, style systems, and color palettes
• IDE integration — view and apply changes in your preferred editor

Setup Workflow

Step 1: Install Stagewise

Download from stagewise.io and follow the onboarding guide to create an account. No CLI or local install required — Stagewise runs entirely in the browser.

Step 2: Connect an AI Provider

Stagewise supports two connection patterns:

Pattern A — Subscription import (easiest):

| Provider | Featured Models | Sign Up | |---|---|---| | OpenRouter | 345+ models via single key | openrouter.ai/keys | | Mistral | Mistral Medium 3.5, Codestral | console.mistral.ai/api-keys | | Moonshot AI (Kimi) | Kimi K3, Kimi K2.7 Code | platform.moonshot.ai | | MiniMax | MiniMax M3, M2.7 | platform.minimax.io |

Pattern B — Bring your own API key for any provider via OpenRouter for maximum flexibility.

Step 3: Start a Session

1. Open Stagewise in your browser
2. Navigate to the target website or open your codebase
3. The coding agent is ready to receive instructions

Pricing

Stagewise offers a tiered model access plan:

| Plan | Price | Limits | |---|---|---| | Free | $0 / month | 3 standard models | | Pro | $20 / month | All models including Frontier and Open-Weights | | Ultra | $200 / month | All models, 15x higher limits than Pro |

Open-Weight Models Available

The project supports open-weight models from multiple providers:

• Moonshot AI: Kimi K3, Kimi K2.7 Code, Kimi K2.6, Kimi K2.5
• Alibaba: Qwen 3-32B, Qwen 3-Coder 30B-A3B
• DeepSeek: DeepSeek V4 Pro, DeepSeek V4 Flash
• MiniMax: MiniMax M3, MiniMax M2.7
• Mistral: Mistral Medium 3.5, Mistral Large 3, Codestral

Practical Evaluation Checklist

• [ ] Can the agent read console errors from a live page?
• [ ] Does connecting a local codebase work without additional CLI setup?
• [ ] Are changes applied temporarily visible without git commits?
• [ ] Does the reverse-engineer feature correctly identify CSS variables and component structure?
• [ ] Is Bring Your Own Key working for OpenRouter?
• [ ] Do open-weight models perform code tasks at usable speed?

Security Notes

• All model traffic routes through the provider’s API — no data processing on Stagewise servers beyond authentication
• Using your own API key (Pattern B) means model providers see your prompts directly
• The agent runs in your browser tab — review changes before applying to a connected codebase

FAQ

Q: Does Stagewise require a local install? A: No. Stagewise runs entirely in the browser. No CLI or desktop app needed.

Q: Can it work with my existing codebase? A: Yes. You can connect a local codebase for permanent edits, or use temporary test changes that do not touch your git history.

Q: Which models does it support? A: 30+ models across OpenRouter, Mistral, Moonshot AI, DeepSeek, MiniMax, and more. Both proprietary (Claude, GPT) and open-weight models are supported.

Q: Is it actually open source? A: Yes. The core project is AGPL-3.0 licensed and lives at github.com/stagewise-io/stagewise.

Q: How does it compare to browser automation tools like Playwright or Puppeteer? A: Stagewise is not an automation framework — it is an IDE with an embedded agent. The agent can read live DOM state and console output, but does not expose a programmatic API for headless runs.

Conclusion

Stagewise stands out from chat-based coding assistants by giving the AI in-browser execution context — it can see what the browser sees, read console errors in real time, and let you verify changes before they touch your codebase. The open-source AGPL-3.0 license and support for 30+ models across multiple providers make it a flexible choice for developers who want to run frontier or open-weight models without vendor lock-in.

For frontend developers specifically, the reverse-engineer feature — which extracts component structure, CSS variables, and color palettes from any live site — is a capability most other tools do not offer at all.

Try it at stagewise.io.