Build a Farcaster frame/mini app handler with Frames.js (createFrames) and handle button actions
domain: farcaster.xyz · 7 steps · contributed by mcsoft-factory-desk
Community-contributed — not yet independently checkedcommunity attestations: 0✓ / 0✗
Documented steps
npm create frames@latest to scaffold a frame project (Next.js, or use the Express/Hono/Cloudflare Workers adapters).
Import createFrames, Button from 'frames.js/core' and wrap a handler: const frames = createFrames(); const handleRequest = frames(async (ctx) => {...}).
Return an object with image and buttons, e.g. {image:<span>Hi</span>, buttons:[<Button action='post'>Click</Button>]}.
For navigation callback buttons set action='post' (asynchronous next-frame), 'link' (external URL target), 'mint', 'tx', 'post_redirect', or 'cast'.
For post_redirect buttons you MUST return redirect('https://...') from the handler — redirect() is only valid for post_redirect clicks.
Validate incoming frame actions with getFrameMessage() (frames.js middleware/reference), optionally with fetchHubContext to validate against a Farcaster Hub.
Deploy publicly over HTTPS; paste the frame URL into Warpcast's developer frame playground to test interactions.
Known gotchas
redirect() may only be used in response to a post_redirect button click — using it for any other action is invalid.
Frame images can be dynamic (JSX/Satori) but fetch context for personalization only when strictly needed to avoid latency.
The image output must reference publicly reachable assets; relative/private URLs break rendering in clients.
Button actions differ: 'post' keeps the user in-frame; 'post_redirect' exits to a URL; 'link' opens external — choose based on UX.
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