Replica lets your whole team describe a screen in plain language and get an interactive prototype built from your own design system. The code is free and open, but the models behind it and a shared Hub are not.
The short answer
- What it is: an AI prototyping tool from GitHub Design, released under the MIT license on October 28, 2026, at github.com/github/replica.
- Who it suits: teams with a design system. GitHub says it builds on your existing components, patterns and documentation, not on generic styles.
- Day one: the GitHub Copilot app, Git, and Node.js with npm, on macOS or Linux. No server, domain or Hub.
- Sharing: an optional, self-hosted Replica Hub lets teammates view prototypes and comment. It needs its own Linux server and domain.
- The catch: an open license does not make model use or hosting free.
Who benefits and who does what
Replica splits the work in two. Designers write the guidance: the components, patterns and documentation the tool must follow. Then anyone on the team, including product managers and engineers, describes an idea in natural language in the GitHub Copilot app.
The prototype appears next to the conversation. You test it, ask for changes, and refine it the same way. Teams can also adapt the open-source tooling and guidance to their product and workflow.
That is GitHub’s own description. It is not a comparison, and nothing here shows Replica beats other prototyping tools.
What a first local session looks like
The repository does not list install commands on its main page. It points to a walkthrough called “Create your first local prototype”, and each walkthrough covers installation. The flow it describes is short:
- Start from a starter or from an existing prototype repository.
- Add your team’s guidance.
- Describe a screen in the Copilot app and watch the prototype run beside the conversation.
Two starters ship with the project. Minimal is a small example app you adapt to your own design system. CoreAI Sandbox has a navigation layout and prebuilt elements such as buttons and menus from Microsoft’s CoreAI design system. The footer also credits Microsoft CoreAI Design.
What designers should prepare
Your guidance is the product. The repository builds it from your team’s components, patterns and documentation, so gather those before the first session. Anyone setting up or adapting a prototype repository, human or agent, should follow docs/prototype-repository-setup.md. Joining an existing team environment is covered in docs/getting-started.md.
What you need for local work versus sharing
Local work needs three things: the GitHub Copilot app, Git, and Node.js with npm. The documented platforms are macOS and Linux. The documented canvas workflow also needs a GitHub sign-in.
Sharing adds Replica Hub, which hosts published prototypes so teammates can explore them and leave comments. Your organization runs it and controls its configuration. Publishing to it also needs the GitHub build action, which local prototyping does not.
The repository lists these requirements for hosted publishing: a Linux server, a dedicated domain with wildcard DNS and HTTPS, network access, and GitHub permissions and approvals. If hosting is blocked, work locally and connect the same repository to a Hub later. Hosting setup is in docs/prototype-environment.md.
| Goal | What you need | Extra cost or limit |
|---|---|---|
| Prototype alone, locally | Copilot app, Git, Node.js and npm on macOS or Linux | GitHub-hosted models need a Copilot plan |
| Share and collect comments | Self-hosted Hub: Linux server, domain with wildcard DNS and HTTPS, approvals | The repository does not state hosting costs |
| Only view or review | Access to a published prototype | No Copilot subscription needed |
The cost map: license, models, hosting
- License: MIT, so the code costs nothing. Bundled fonts use the SIL Open Font License.
- Models: GitHub-hosted models require a Copilot plan. Or bring your own model provider and skip the plan. Then the provider’s costs and terms apply. That option is in public preview and may change.
- Hosting: a Hub means a server and a domain that your organization pays for and runs.
Where Hub data goes
Hub stores publishing and review events in its own database for 90 days. Those events do not cover offline work, local editing or interactions inside prototype previews. Sending them to Segment, Mixpanel or a custom HTTPS endpoint needs a repository administrator to configure it, and Replica does not send activity records to GitHub automatically.
Self-hosted does not mean fully internal. GitHub services and your AI provider each have their own data handling. Read hub/docs/analytics.md, hub/docs/security.md and hub/docs/backups-and-restore.md before you connect a Hub.
Start here
- Confirm your team uses macOS or Linux.
- Choose your model route: a Copilot plan, or your own provider.
- Pick Minimal or CoreAI Sandbox, add your design guidance, and follow the first-prototype walkthrough.
- Test with real screens locally. Ask about a Hub only if you need teammates to comment.
Not covered by the sources: Windows for local prototyping, right-to-left language support, hosting costs, and minimum versions of Node.js, npm and Git. The repository says support is limited to what its support policy describes.
Questions and answers
Do I need a server to try Replica?
No. The README says you can start locally without a server, domain or Replica Hub, then connect the same repository to a Hub later.
Do the people who review prototypes need Copilot?
No. Viewing a finished prototype or reviewing it in Hub does not require a Copilot subscription.
Can I use my own model provider?
Yes, without a Copilot plan. It is a public preview that may change, and the provider’s costs and terms apply.
Who can build prototypes: only designers?
No. Designers set the guidance. Designers, product managers and engineers can all create and refine prototypes by describing them in the Copilot app.
Does a self-hosted Hub keep all data inside my company?
No. Events stay in the Hub’s database for 90 days, but GitHub services and your AI provider have their own data terms.
Terms in plain language
- Design system: a team’s shared set of components, patterns and rules for how a product looks and behaves.
- Prototype: a clickable draft of a screen or flow used to test an idea before building it.
- MIT license: a permissive open-source license for the code. It says nothing about the cost of services you connect.
- BYOK: bring your own key, meaning you connect your own model provider.
- Wildcard DNS: a domain setting that lets many subdomains point to the same server.
This article is based on the GitHub announcement and repository. We did not install or run Replica.
Sources
- GitHub changelog: Introducing Replica, an open-source AI prototyping tool (October 28, 2026)
- GitHub repository: github/replica
Facts read on 29 October 2026
