htmx Endpoint Design

Use this skill when the hard part is the server/browser contract: which element makes the request, which endpoint handles it, what HTML comes back, and where that HTML lands.

Contract First

Define the endpoint contract before writing attributes:

• Request source: the element that sends the request.
• HTTP method: GET for safe reads; POST, PUT, PATCH, or DELETE for mutations when the server/framework supports them.
• Input data: normal form fields, included elements, path params, or explicit values.
• Response shape: full page, partial fragment, empty response, redirect, or event-only response.
• Swap target: the element to replace or update.
• Follow-up effects: events, out-of-band fragments, URL changes, focus changes, and messages.

Endpoint Workflow