Poly vs Replit for building with AI together

Replit and Poly both let a team build software with AI in a browser, and they make opposite bets about what the team shares. Replit shares the project: each teammate opens their own thread with Replit Agent, tasks run in isolated copies, and the agent merges them. Poly (usepoly.co) shares the session: one AI, one timeline, and every member can prompt it, approve its changes and undo its turns. Replit is the more complete platform, with an IDE, hosting and deployment built in. Poly is the narrower tool built for a small group steering one build together, including people who do not code.

Where Replit is stronger

• It is a whole platform. An editor, a shell, a database, hosting, custom domains and deployments in one place. A Poly room builds and previews; publishing gives a static snapshot, and anything with a backend is previewable but not yet publishable.
• Parallel work. Pro runs up to ten agent tasks at once across fifteen builders, each in its own copy, with a Kanban board to track them. Poly runs one turn at a time per room, on purpose.
• Maturity. Years of multiplayer editing, mobile apps, viewer seats for stakeholders, and a credits program for funded startups.

Where Poly is stronger

• One session. Everyone sees the same prompt, the same reply and the same change as it happens, and the person who typed the prompt is not a bottleneck: any member can answer the AI's question or approve its edit.
• A say before it lands. In Replit, a finished task waits in "Ready" for review. In Poly's approval modes, the AI's proposed change is a card on every screen before it happens, in plain language, and the timeline records who decided.
• Receipts. Every turn names who ran it, which model, how long it took and what it cost in credits. Replit pools plan credits across the project.
• The non-coder drives. Replit's role for a non-builder is a read-only viewer seat. In Poly, the person who cannot code prompts, approves and reverts like anyone else.
• Two labs. Each member picks Claude or ChatGPT per turn in the same room.
• A channel the AI cannot read. Poly's group chat and polls are hidden from the agent. Replit's in-editor chat is visible to its assistant.

Pricing, side by side

Replit Core is $20 a month for one project with up to five seats and one background task at a time; Pro is $100 for up to fifteen builders, ten parallel tasks and fifty viewers. Poly is free to start with no card; a person who runs the AI pays $20 a month for Pro or $50 for Max, and watching, chatting and approving are free for everyone. A team of five where two people run the AI pays Poly $40 and Replit $20 or $100 depending on how many parallel tasks they need.

Which should you pick?

• You want to ship a product with hosting, a database and deploys from one tool: Replit.
• Several engineers want to run many agent tasks in parallel: Replit Pro.
• A small group, including someone who does not code, wants to steer one AI together and see every change before it lands: Poly.
• You already have a repo and a deploy pipeline and want the AI's work visible and attributable: Poly, connected to the repo; it pushes to a branch.

They also combine. A Poly room can work on a repository that a Replit project also uses; the code meets in git.