Multi-step form

multi-step-form is the blessed wizard: the server owns the current step and a draft of everything entered. The client is one region (whole-step outerHTML swaps), one form per step, and an hc-stepper the server re-renders with every response — no client-side step state, no hidden fields accumulating across steps, no JavaScript beyond htmx. Stable under the markup versioning policy.

Scaffold

npx @hypermedia-components/cli add multi-step-form copies this recipe’s scaffold (recipe.html, expanded.html, contract.md, checks.json); npx @hypermedia-components/cli validate machine-checks your copy. The full contract lives in recipes/multi-step-form/contract.md.

Live demo

Walk the wizard below — Next validates the step (natively via required, and authoritatively on the server, whose 422 answers a field-errors fragment), Back never validates even with a blank field, and the final step redirects to a plain confirmation page with a link back here. The endpoint is a namespaced demo implementation of the server responses under api/recipes/multi-step-form/.

The markup (a middle step)

<section id="wizard">
  <ol class="hc-stepper">
    <li class="hc-stepper__step" data-state="complete">
      <span class="hc-stepper__marker" aria-hidden="true">✓</span>
      <span class="hc-stepper__label">Account
        <span class="hc-sr-only">(completed)</span></span>
    </li>
    <li class="hc-stepper__step" aria-current="step">
      <span class="hc-stepper__marker" aria-hidden="true">2</span>
      <span class="hc-stepper__label">Profile</span>
    </li>
    <li class="hc-stepper__step">
      <span class="hc-stepper__marker" aria-hidden="true">3</span>
      <span class="hc-stepper__label">Review</span>
    </li>
  </ol>

  <form method="post" action="/signup/2"
        data-hx-post="/signup/2"
        data-hx-target="#wizard" data-hx-swap="outerHTML"
        data-hx-disabled-elt="find button[type=submit]">
    <div id="wizard-errors"></div>
    …step 2 fields, pre-filled from the draft…
    <button class="hc-button" type="submit" name="nav" value="back"
            formnovalidate>Back</button>
    <button class="hc-button" data-variant="primary" type="submit"
            name="nav" value="next">Next</button>
  </form>
</section>

Both nav directions are named submits of the same form (name="nav"), so htmx and the native no-JS path send identical bodies, and the current step’s entries always travel with the navigation.

Back must never validate

formnovalidate on the back button is the load-bearing native detail: without it, required fields on the current step trap the user in the browser’s validation bubbles. With it, back always works — the server stores whatever arrived as a draft (drafts are never validated; only “next” validates), and a back-then-next round-trip is lossless. hc validate errors on a back button without it.

Server responses

Case	Response
nav=next, valid	200 — the complete #wizard fragment for the following step: stepper re-rendered (this step now ✓), fields pre-filled from the draft
nav=back	200 — the previous step’s fragment; the posted fields were merged into the draft without validation
nav=next, invalid	422 + HX-Retarget: #wizard-errors + HX-Reswap: innerHTML with the field-errors fragment — the step is not re-rendered, the user’s in-progress values stay untouched
final nav=next	the mutating-form completion: 204 + HX-Redirect (htmx) / 303 Location (no-JS)

Step URLs are real (/signup/1, /signup/2, …): refresh and deep links land on the server’s idea of the current step, and without JavaScript the wizard is simply classic pages.

Accessibility

The stepper announces state structurally (<ol> + aria-current="step" + sr-only (completed)); formnovalidate keeps keyboard users un-trapped; the 422 path preserves field-errors’ focus management; put the step heading first in each fragment so reading order restarts sensibly after a swap.

Notes

• Draft storage (session, draft row) is your framework’s concern — the contract only requires lossless back-then-next round-trips and unvalidated drafts.
• File inputs don’t round-trip through drafts — upload files separately (file-upload) and reference the stored upload in the draft.
• Completed stepper steps may be links to their step URLs if the flow allows revisiting.

The claims here — the stepper re-render, the lossless draft round-trip, back escaping an invalid step, the value-preserving 422, completion — are pinned by a real-htmx browser test (test-browser/multi-step-form.spec.mjs).

Related

• Stepper — the zero-JS indicator.
• Mutating form recipe — the completion branching and the 422 allowance.
• Field errors recipe — the validation fragment.