Released 2026-06-03. Playgrounds can now run your own server-side code — a secure backend you write in the editor that your page can call, with access to your sheets, tools, agents, and workflows.
Server-side code for playgrounds
- A new Server tab in the playground editor lets you write backend functions that run on FlowFn, never in the visitor's browser. Use it for logic or secrets you don't want to ship to the page.
- Call a function from your page with
await flowfn.server.call('myFunction', { ...inputs }). Inside, each function receives actxwith your data sheets, your registered tools and fetch entries, and the ability to start an agent or workflow. - Use the Functions panel on the Server tab to declare each function and list its inputs; whatever the function returns is sent to the page. Add to code drops a starter
exports.<name>into the editor for you to fill in. - Declaring an enabled function makes it callable both from your editor preview and by visitors of your published page — handy for sign-up forms, lookups, or anything that needs your backend. Calls validate their inputs and are rate-limited, with a daily cap per playground. Code you
exportbut don't declare in the panel stays private to you. - The AI assistant can help you write and refine Server-tab code, the same way it helps with your page's HTML, CSS, and JavaScript.
- Available on plans that include playground server-side code.