Starcat Developer
The in-browser builder that builds and edits one app's code from conversation
Starcat Developer is the builder inside each Stardeck project. Describe what you want; it writes the UI, database, auth, and business logic for that app.
Starcat Developer is the in-browser option, for when you can't install anything. To build with Claude Code, Codex or Cursor on your computer, follow the Quickstart. For the agent that works across your organization, see Starcat.
What the Agent Can Do
- Write and edit code, design UIs, and manage the database schema and migrations.
- Search the web for API docs and design references.
- Generate images (Image Generation) and find stock photos.
- Break large work into tasks and track progress.
Example requests:
- "Add user login and admin access": auth with roles and Stardeck single sign-on.
- "Let users upload files": file storage for images, PDFs, video.
- "Add payment processing": Beam Checkout, Stripe Connect, or a gateway such as Omise. See Payments.
- "Send email notifications": see Email.
- "Rebuild my current website": replicate an existing site with a new design.
Question Forms
When the agent needs input, it shows a form instead of a plain-text question: visual selection cards, checkboxes, dropdowns, text inputs, and a custom option. Every form has an optional notes field.
Live Visual Previews
Before writing code, the agent renders real HTML previews in the chat. You can scroll and hover them. It uses them for design direction questions, feature previews, and comparing layouts side by side. Point at what you want changed.
Model
Starcat Developer runs on Claude Sonnet 5.5. There's no model or tier to pick. Each message counts toward your plan's AI usage based on the work it takes, so a small edit costs less than a large feature.
Ultra
Ultra, at the top of the mode selector, is the max-power Agent mode for a large change built and verified in one run; see Starcat Developer Ultra.
Recommended Workflow
- Plan first. For a new app or large feature, use Plan mode. Agree on requirements, previews, and phases.
- Build from the plan. Approve it, then switch to Agent mode (or Ultra for a large, fully specified change).
- Refine in small steps. Quick fixes and copy changes are cheap.
Uploading Assets
Upload files in the chat: logos, brand images, photos, PDFs, spreadsheets, and screenshots of designs. Common image (PNG, JPG, SVG, WebP) and document (PDF, CSV, TXT) types work.
- Upload brand assets early so the agent uses them in every design.
- The agent can see images. Share a screenshot of a bug, a mockup to build, or a site you like.
- Uploaded images can be references for Image Generation.
Loading Data
To import existing data (products, customers, menus, blog posts):
- Export it as CSV or a spreadsheet with clear column headers.
- Drag it into the chat and say what it is: "Here's my product catalog. Each row is a product with name, price, description, and category."
- The agent shows how it will map columns to your database. Confirm or correct.
- It loads the data.
For large imports, start with a small sample.
Tips
- Plain language works. "Make the header stick to the top when I scroll" is enough.
- Be specific: "Add a contact form with name, email, and message that emails me" beats "Add a form".
- Ask when unsure: "What's missing from my site?" or "Can I accept payments here?"
- Answer the agent's questions with specifics, not "the usual stuff".
- Build one feature at a time and refine after seeing the result.
