SvelteKit contact form �Formspree alternative with AI spam filtering

Contact form for SvelteKit, posting JSON to SmartForm AI from a form action.

What you're POSTing

The endpoint accepts a standard HTML form POST or JSON via AJAX. Two kinds of fields:

Your form fields â€?name, email, message, whatever you want. Every non-reserved field lands in your dashboard as a column in the submissions table.

Reserved fields â€?names starting with _ are interpreted by the API, not stored:

Field	Purpose
_gotcha	Honeypot. Keep it empty. Hidden from humans via CSS; bots fill it automatically. Any non-empty value silently drops the submission. Add this to every form.
_hp_email / _website / _url / _phone	Honeypot aliases for _gotcha (WordPress / WPForms / Contact Form 7 migrations). Same drop semantics.
_next	Same-origin URL to redirect to after a successful submission. Browser POST results in a 302 here. AJAX calls (with Accept: application/json) get the same value back as next_url in the JSON response. Only http(s) and in-site paths allowed.
_subject	Override the AI-generated email subject line. Max 200 chars; control characters stripped.
X-Gotcha header	Same as _gotcha for JSON requests where you can't add a hidden form field.

Field names are Formspree-compatible â€?migrating from formspree.io/f/{form_id} requires no renaming.

Setup

1. Get a form ID at https://usesmartform.com/dashboard.
2. Clone, install, configure, run:

   git clone https://github.com/smartformai/smartform-example-sveltekit.git
   cd smartform-example-sveltekit
   npm install
   cp .env.example .env
   # edit .env �SMARTFORM_FORM_ID=your_real_id
   npm run dev

3. Open http://localhost:5173/contact, submit, check your dashboard.

The form action

src/routes/contact/+page.server.ts handles the POST and forwards to SmartForm. The page itself (+page.svelte) is a normal HTML form.

// src/routes/contact/+page.server.ts
import type { Actions } from './$types';

export const actions: Actions = {
  default: async ({ request }) => {
    const data = await request.formData();
    const payload: Record<string, FormDataEntryValue> = {};
    data.forEach((v, k) => { payload[k] = v; });

    const r = await fetch(`${process.env.SMARTFORM_ENDPOINT ?? 'https://api.usesmartform.com'}/api/v1/f/${process.env.SMARTFORM_FORM_ID}`, {
      method:  'POST',
      headers: { 'Content-Type': 'application/json', 'Accept': 'application/json' },
      body:    JSON.stringify(payload),
    });

    return { ok: r.ok, status: r.status, body: await r.json() };
  },
};

src/routes/contact/+page.svelte renders the form and reads form from props to show status.

How the API works

• POST {endpoint}/api/v1/f/{form_id} â€?JSON or form-data, no API key.
• Response: { success, message, submission_id, is_spam, intent, next_url }.

For the full contract, see https://usesmartform.com/docs.

Deploy

npm run build         # ./build
npx vercel --prod     # or `wrangler pages deploy ./build`

Set SMARTFORM_FORM_ID in your hosting provider's environment variables.

FAQ

Is there a free tier?

Yes. AI spam filtering is enabled by default on every plan. AI intent classification and high-value lead detection require a paid plan (Pro or Business) �the dashboard enforces this and returns HTTP 402 if you try to enable them on a free workspace.

Do I need an API key?

No. The form posts directly to a public endpoint using only an 8-char form ID, which is non-enumerable. The example also includes a hidden _gotcha honeypot field so naive bots cannot submit.

Do I need a SvelteKit server?

The example uses a SvelteKit form action so the form ID stays server-side. It runs on Vercel, Netlify, Cloudflare and Node adapters without code changes.

Related examples

Next.js contact form | Nuxt contact form | Astro contact form

License

MIT.