Dokumentace SimplyForms

<form action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID" method="POST">
  <input type="email" name="email" required />
  <button type="submit">Odeslat</button>
</form>

git clone https://github.com/simplyforms/public-claude-skill ~/.claude/skills/simplyforms

Here's my contact form at ./about.html. Wire it up to SimplyForms.
My form_id is YOUR_FORM_ID, I'm on the FREE plan.
Show me an inline thank-you message on success.

Connect this website's form to SimplyForms (https://simplyforms.app), a hosted form backend that emails every submission to the site owner and does not store it.
- Endpoint: POST https://api.simplyforms.app/v1/forms/FORM_ID. FORM_ID is in the SimplyForms dashboard; ask me for it. Submitting needs no API key.
- Keep the existing field names: they become the labels in the email. A field named "subject" sets the email subject; fields whose name starts with "_" are left out of the email.
- Either set the form's action to the endpoint with method="POST" (works without JavaScript: the visitor lands on a SimplyForms thank-you page, or on the URL in a hidden "_redirect" field when it is on the same https site), or submit with fetch(endpoint, { method: "POST", body: new FormData(form) }) and show an inline thank-you when the response is 200 with {"success": true}.
- For file inputs use enctype="multipart/form-data" (FormData does this). Attachment limit per submission: Free 1 MB, Standard 5 MB, Extend 50 MB.
- Errors come back as JSON with "ok": false, "code" and "message" at the top level; read body.code and body.message (the "detail" copy is deprecated).
- Add no CAPTCHA on the Free plan. On paid plans spam protection is switched on in the dashboard; the widget is described in the full guide.
Full guide: https://simplyforms.app/llms-full.txt

<form action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID" method="POST">
  <label for="name">Jmeno:</label>
  <input type="text" id="name" name="name" required />

  <label for="email">Email:</label>
  <input type="email" id="email" name="email" required />

  <label for="message">Zprava:</label>
  <textarea id="message" name="message" rows="5" required></textarea>

  <button type="submit">Odeslat zpravu</button>
</form>

<form action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID" method="POST">
  <!-- Optional: your own thank-you page instead of ours.
       A path like /thanks works too. -->
  <input type="hidden" name="_redirect" value="https://example.com/thanks" />

  <input type="email" name="email" required />
  <textarea name="message" required></textarea>
  <button type="submit">Send</button>
</form>

<form id="multi-step-form" action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID" method="POST">
  <!-- Krok 1: Osobni udaje -->
  <div class="step step-1 active">
    <h3>Krok 1: Osobni udaje</h3>
    <input type="text" name="firstName" placeholder="Jmeno" required />
    <input type="text" name="lastName" placeholder="Prijmeni" required />
    <button type="button" onclick="nextStep()">Dalsi</button>
  </div>

  <!-- Krok 2: Kontakt -->
  <div class="step step-2">
    <h3>Krok 2: Kontaktni udaje</h3>
    <input type="email" name="email" placeholder="Email" required />
    <input type="tel" name="phone" placeholder="Telefon" />
    <button type="button" onclick="prevStep()">Zpet</button>
    <button type="button" onclick="nextStep()">Dalsi</button>
  </div>

  <!-- Krok 3: Zprava -->
  <div class="step step-3">
    <h3>Krok 3: Vase zprava</h3>
    <textarea name="message" placeholder="Zprava" rows="5" required></textarea>
    <button type="button" onclick="prevStep()">Zpet</button>
    <button type="submit">Odeslat</button>
  </div>
</form>

<script>
let currentStep = 1;
const totalSteps = 3;

function nextStep() {
  if (currentStep < totalSteps) {
    document.querySelector(`.step-${currentStep}`).classList.remove('active');
    currentStep++;
    document.querySelector(`.step-${currentStep}`).classList.add('active');
  }
}

function prevStep() {
  if (currentStep > 1) {
    document.querySelector(`.step-${currentStep}`).classList.remove('active');
    currentStep--;
    document.querySelector(`.step-${currentStep}`).classList.add('active');
  }
}
</script>

<style>
.step { display: none; }
.step.active { display: block; }
</style>

<form
  action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID"
  method="POST"
  enctype="multipart/form-data">

  <label for="name">Jmeno:</label>
  <input type="text" id="name" name="name" required />

  <label for="email">Email:</label>
  <input type="email" id="email" name="email" required />

  <label for="file">Nahrat soubor:</label>
  <input
    type="file"
    id="file"
    name="attachment"
    accept=".pdf,.doc,.docx,.jpg,.png"
    required />

  <p class="file-info">
    Podporovane formaty: PDF, DOC, DOCX, JPG, PNG<br>
    Maximalni velikost: 50MB (Extend plan)
  </p>

  <button type="submit">Odeslat s prilohou</button>
</form>

<form action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID" method="POST">

  <!-- subject -> Subject: header of the delivered e-mail -->
  <input type="text" name="subject" placeholder="Email subject" required />

  <!-- from_name -> sender name in your inbox: "Acme website via SimplyForms" -->
  <input type="hidden" name="from_name" value="Acme website" />

  <!-- Extra recipients: configure them under Recipients in the dashboard.
       The legacy ccemail field is deprecated and cannot add a new recipient. -->

  <!-- Regular fields (appear in the e-mail body) -->
  <input type="text" name="name" placeholder="Your name" required />
  <input type="email" name="email" placeholder="Your e-mail" required />
  <textarea name="message" placeholder="Your message" required></textarea>

  <!-- _-prefixed -> kept out of the e-mail body (use for hidden context) -->
  <input type="hidden" name="_source" value="homepage-hero" />

  <!-- _redirect -> your own thank-you page after a plain form submit
       (same https site as the form; otherwise our thank-you page) -->
  <input type="hidden" name="_redirect" value="https://example.com/thanks" />

  <button type="submit">Send</button>
</form>

<form action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID" method="POST">
  <input type="text" name="name" placeholder="Jmeno" required />
  <input type="email" name="email" placeholder="Email" required />
  <textarea name="message" placeholder="Zprava" required></textarea>

  <!-- Cloudflare Turnstile -->
  <div class="cf-turnstile" data-sitekey="YOUR_SITE_KEY"></div>

  <button type="submit">Odeslat</button>
</form>

<script src="https://challenges.cloudflare.com/turnstile/v0/api.js" async defer></script>

<form action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID" method="POST">
  <input type="text" name="name" placeholder="Jmeno" required />
  <input type="email" name="email" placeholder="Email" required />

  <!-- reCAPTCHA v3 token -->
  <input type="hidden" name="g-recaptcha-response" id="recaptchaResponse" />

  <button type="submit">Odeslat</button>
</form>

<script src="https://www.google.com/recaptcha/api.js?render=YOUR_SITE_KEY"></script>
<script>
grecaptcha.ready(function() {
  document.querySelector('form').addEventListener('submit', function(e) {
    e.preventDefault();
    grecaptcha.execute('YOUR_SITE_KEY', {action: 'submit'}).then(function(token) {
      document.getElementById('recaptchaResponse').value = token;
      e.target.submit();
    });
  });
});
</script>

<form action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID" method="POST">
  <input type="text" name="name" placeholder="Jmeno" required />
  <input type="email" name="email" placeholder="Email" required />
  <textarea name="message" placeholder="Zprava" required></textarea>

  <!-- SimplyForms Protection widget — loads JS from the SimplyForms API (self-hosted) -->
  <script type="module" src="https://api.simplyforms.app/sf/widget.js"></script>
  <sf-captcha challengeurl="https://api.simplyforms.app/sf/challenge?form_id=YOUR_FORM_ID"></sf-captcha>

  <button type="submit">Odeslat</button>
</form>

<form action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID" method="POST">
  <input type="email" name="email" required />
  <textarea name="message" required></textarea>

  <script type="module" src="https://api.simplyforms.app/sf/widget.js"></script>
  <!-- auto="onsubmit" defers PoW until the user clicks Send;
       autoreset clears the verified payload after every submit. -->
  <sf-captcha
    challengeurl="https://api.simplyforms.app/sf/challenge?form_id=YOUR_FORM_ID"
    auto="onsubmit"
    autoreset
  ></sf-captcha>

  <button type="submit">Send</button>
</form>

<form id="contactForm" action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID" method="POST">
  <input type="email" name="email" required />
  <textarea name="message" required></textarea>

  <script type="module" src="https://api.simplyforms.app/sf/widget.js"></script>
  <sf-captcha
    challengeurl="https://api.simplyforms.app/sf/challenge?form_id=YOUR_FORM_ID"
    auto="onsubmit"
  ></sf-captcha>

  <button type="submit">Send</button>
</form>

<script>
  const form = document.getElementById('contactForm');
  form.addEventListener('submit', async (e) => {
    e.preventDefault();
    try {
      const res = await fetch(form.action, { method: 'POST', body: new FormData(form) });
      if (res.ok) {
        // ...show your own success UI here
      } else {
        // ...show your own error UI here
      }
    } finally {
      // Always reset — the server consumed the token whether it accepted
      // or rejected the submission, so a re-submit would hit ALTCHA_REPLAY
      // without a fresh challenge. Dispatching the event resets ONLY the
      // captcha widget; form fields stay intact (form.reset() would wipe
      // them).
      form.dispatchEvent(new Event('reset'));
    }
  });
</script>

<form
  id="contact-form"
  action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID"
  method="POST"
  class="contact-form">

  <div class="form-group">
    <label for="fullName">Cele jmeno *</label>
    <input
      type="text"
      id="fullName"
      name="fullName"
      required
      minlength="2" />
  </div>

  <div class="form-row">
    <div class="form-group">
      <label for="email">Email *</label>
      <input type="email" id="email" name="email" required />
    </div>

    <div class="form-group">
      <label for="phone">Telefon</label>
      <input type="tel" id="phone" name="phone" pattern="[0-9]{9,}" />
    </div>
  </div>

  <div class="form-group">
    <label for="subject">Predmet *</label>
    <select id="subject" name="subject" required>
      <option value="">Vyberte predmet</option>
      <option value="general">Obecny dotaz</option>
      <option value="support">Technicka podpora</option>
      <option value="sales">Obchodni dotaz</option>
      <option value="other">Jine</option>
    </select>
  </div>

  <div class="form-group">
    <label for="message">Zprava *</label>
    <textarea
      id="message"
      name="message"
      rows="6"
      required
      minlength="10"></textarea>
  </div>

  <div class="form-group">
    <label class="checkbox-label">
      <input type="checkbox" name="newsletter" value="yes" />
      Chci odebirat newsletter
    </label>
  </div>

  <div class="form-group">
    <label class="checkbox-label">
      <input type="checkbox" name="gdpr" required />
      Souhlasim se zpracovanim osobnich udaju *
    </label>
  </div>

  <button type="submit" class="btn-submit">
    Odeslat zpravu
  </button>

  <div class="form-success" style="display: none;">
    Zprava byla uspesne odeslana!
  </div>
</form>

<script>
document.getElementById('contact-form').addEventListener('submit', function(e) {
  e.preventDefault();
  const form = this;
  const formData = new FormData(form);

  fetch(form.action, {
    method: 'POST',
    body: formData
  })
  .then(response => response.json())
  .then(data => {
    form.style.display = 'none';
    document.querySelector('.form-success').style.display = 'block';
  })
  .catch(error => {
    alert('Chyba pri odesilani formulare. Zkuste to prosim znovu.');
  });
});
</script>

<form
  action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID"
  method="POST"
  class="newsletter-form">

  <h3>Prihlaste se k odberu</h3>
  <p>Ziskejte nejnovejsi tipy a triky primo do emailu</p>

  <div class="newsletter-input">
    <input
      type="email"
      name="email"
      placeholder="vas@email.cz"
      required />
    <button type="submit">Odeslat</button>
  </div>

  <p class="newsletter-note">
    Zadny spam. Odhlasit se muzete kdykoli.
  </p>
</form>

<style>
.newsletter-form {
  max-width: 500px;
  margin: 0 auto;
  padding: 30px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  border-radius: 16px;
  text-align: center;
}

.newsletter-input {
  display: flex;
  gap: 10px;
  margin: 20px 0;
}

.newsletter-input input {
  flex: 1;
  padding: 12px;
  border: none;
  border-radius: 8px;
  font-size: 16px;
}

.newsletter-input button {
  padding: 12px 24px;
  background: white;
  color: #667eea;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
}

.newsletter-note {
  font-size: 14px;
  opacity: 0.9;
}
</style>

1. Sign in to the SimplyForms dashboard
2. Open "Integrations" in the sidebar
3. In the "Webhook" section, enable it and enter your URL
4. (Optional) toggle "Include metadata" — off by default
5. Save — a signing secret is generated automatically

{
  "formId": "YOUR_FORM_ID",
  "timestamp": 1736519400,
  "data": {
    "name": "Jan Novak",
    "email": "jan.novak@example.com",
    "message": "Dobry den, mam zajem o vas produkt."
  }
  // "metadata": { ipAddress, userAgent, referrer }
  // is ONLY included if you explicitly opt in per form.
}

// Express.js priklad
const express = require('express');
const app = express();

app.use(express.json());

app.post('/api/webhook', async (req, res) => {
  try {
    const { formId, submissionId, data, metadata } = req.body;

    // Validace signature (doporuceno)
    const signature = req.headers['x-simplyforms-signature'];
    if (!verifySignature(signature, req.body)) {
      return res.status(401).json({ error: 'Invalid signature' });
    }

    // Zpracovani dat
    console.log('Novy formular od:', data.email);

    // Ulozeni do databaze
    await db.submissions.create({
      formId,
      submissionId,
      email: data.email,
      name: data.name,
      message: data.message,
      receivedAt: new Date()
    });

    // Notifikace do Slacku, CRM, etc.
    await sendToSlack(data);

    // Vzdy odpovezte status 200
    res.status(200).json({ received: true });

  } catch (error) {
    console.error('Webhook error:', error);
    res.status(500).json({ error: 'Internal error' });
  }
});

function verifySignature(signature, body) {
  const crypto = require('crypto');
  const secret = process.env.SIMPLYFORMS_WEBHOOK_SECRET;
  const hash = crypto
    .createHmac('sha256', secret)
    .update(JSON.stringify(body))
    .digest('hex');
  return signature === hash;
}

app.listen(3000);

# Instalace ngrok
npm install -g ngrok

# Spusteni tunelu
ngrok http 3000

# Pouzijte vygenerovanou URL (napr. https://abc123.ngrok.io)
# jako webhook URL v SimplyForms dashboardu

<form id="validated-form" action="https://api.simplyforms.app/v1/forms/YOUR_FORM_ID" method="POST">
  <div class="form-group">
    <label for="email">Email:</label>
    <input type="email" id="email" name="email" required />
    <span class="error-message" id="email-error"></span>
  </div>

  <div class="form-group">
    <label for="phone">Telefon (CZ format):</label>
    <input type="tel" id="phone" name="phone" required />
    <span class="error-message" id="phone-error"></span>
  </div>

  <div class="form-group">
    <label for="age">Vek (18+):</label>
    <input type="number" id="age" name="age" required />
    <span class="error-message" id="age-error"></span>
  </div>

  <button type="submit">Odeslat</button>
</form>

<script>
const form = document.getElementById('validated-form');

const validators = {
  email: (value) => {
    const regex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
    if (!regex.test(value)) {
      return 'Zadejte platnou emailovou adresu';
    }
    const blocked = ['tempmail.com', 'throwaway.email'];
    const domain = value.split('@')[1];
    if (blocked.includes(domain)) {
      return 'Pouzijte prosim trvalou emailovou adresu';
    }
    return null;
  },

  phone: (value) => {
    const regex = /^(\+420)?[0-9]{9}$/;
    if (!regex.test(value.replace(/\s/g, ''))) {
      return 'Zadejte platne ceske telefonni cislo';
    }
    return null;
  },

  age: (value) => {
    const age = parseInt(value);
    if (isNaN(age) || age < 18) {
      return 'Musite byt starsi 18 let';
    }
    if (age > 120) {
      return 'Zadejte prosim realny vek';
    }
    return null;
  }
};

Object.keys(validators).forEach(fieldName => {
  const field = document.getElementById(fieldName);
  const errorSpan = document.getElementById(`${fieldName}-error`);

  field.addEventListener('blur', () => {
    const error = validators[fieldName](field.value);
    if (error) {
      errorSpan.textContent = error;
      field.classList.add('invalid');
    } else {
      errorSpan.textContent = '';
      field.classList.remove('invalid');
    }
  });
});

form.addEventListener('submit', (e) => {
  e.preventDefault();
  let isValid = true;

  Object.keys(validators).forEach(fieldName => {
    const field = document.getElementById(fieldName);
    const errorSpan = document.getElementById(`${fieldName}-error`);
    const error = validators[fieldName](field.value);

    if (error) {
      errorSpan.textContent = error;
      field.classList.add('invalid');
      isValid = false;
    }
  });

  if (isValid) {
    form.submit();
  } else {
    alert('Opravte prosim chyby ve formulari');
  }
});
</script>

<style>
.error-message {
  color: #e53e3e;
  font-size: 14px;
  display: block;
  margin-top: 5px;
}

input.invalid {
  border-color: #e53e3e;
  background-color: #fff5f5;
}
</style>

{
  "validationRules": {
    "email": {
      "required": true,
      "type": "email",
      "blockedDomains": ["tempmail.com", "guerrillamail.com"]
    },
    "age": {
      "required": true,
      "type": "number",
      "min": 18,
      "max": 120
    },
    "phone": {
      "required": false,
      "pattern": "^(\\+420)?[0-9]{9}$"
    },
    "message": {
      "required": true,
      "minLength": 10,
      "maxLength": 1000
    }
  }
}

const emailInput = document.getElementById('email');
const emailError = document.getElementById('email-error');

emailInput.addEventListener('blur', async () => {
  const email = emailInput.value;

  clearTimeout(emailInput.debounceTimer);
  emailInput.debounceTimer = setTimeout(async () => {

    try {
      const response = await fetch('/api/check-email', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ email })
      });

      const data = await response.json();

      if (data.exists) {
        emailError.textContent = 'Tento email je jiz zaregistrovan';
        emailInput.classList.add('invalid');
      } else {
        emailError.textContent = '';
        emailInput.classList.remove('invalid');
      }
    } catch (error) {
      console.error('Validation error:', error);
    }

  }, 500);
});

Predmet: Novy formular z example.com

Dobry den,

obdrzeli jste novy formular od:

Jmeno: Jan Novak
Email: jan.novak@example.com
Telefon: +420777123456

Zprava:
Dobry den, mam zajem o vas produkt.

---
Odeslano pres SimplyForms
ID: sub_xyz789
Cas: 10.1.2025 14:30

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width,initial-scale=1">
  <style>
    body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
           background: #f3f4f6; margin: 0; padding: 32px 12px; }
    .card { background: #fff; border-radius: 12px; max-width: 600px;
            margin: 0 auto; overflow: hidden; }
    .header { background: #111827; color: #fff; padding: 28px 32px; }
    .header h1 { margin: 0; font-size: 20px; }
    .body { padding: 28px 32px; }
    .field-label { font-size: 11px; font-weight: 600; text-transform: uppercase;
                   letter-spacing: .05em; color: #6b7280; padding-top: 12px; }
    .field-value { font-size: 15px; color: #111827; padding-bottom: 12px;
                   border-bottom: 1px solid #f3f4f6; }
    .footer { background: #fafafa; padding: 16px 32px; font-size: 12px;
              color: #9ca3af; text-align: center; }
  </style>
</head>
<body>
  <div class="card">
    <div class="header">
      <h1>New form submission</h1>
    </div>
    <div class="body">
      <!-- Reference individual fields by name attribute -->
      <div class="field-label">Name</div>
      <div class="field-value">{{ name }}</div>

      <div class="field-label">Email</div>
      <div class="field-value">{{ email }}</div>

      <div class="field-label">Message</div>
      <div class="field-value">{{ message }}</div>
    </div>
    <div class="footer">Sent via SimplyForms</div>
  </div>
</body>
</html>

<!-- Loop over all submitted fields (any form) -->
{% for label, value in fields.items() %}
  <div class="field-label">{{ label }}</div>
  <div class="field-value">{{ value }}</div>
{% endfor %}

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
</head>
<body style="font-family: sans-serif; max-width: 600px; margin: 0 auto; padding: 20px;">
  <h2>Dekujeme za Vasi zpravu!</h2>

  <p>Mily/a {{name}},</p>

  <p>Dekujeme za vyplneni formulare. Vasi zpravu jsme obdrzeli a odpovime Vam do 24 hodin.</p>

  <div style="background: #f7fafc; padding: 20px; border-radius: 8px; margin: 20px 0;">
    <p><strong>Shrnuti Vasi zpravy:</strong></p>
    <p>{{message}}</p>
  </div>

  <p>Pokud mate nalehavou otazku, kontaktujte nas na <a href="tel:+420777123456">+420 777 123 456</a>.</p>

  <p>S pozdravem,<br>
  Vas tym</p>

  <hr style="border: none; border-top: 1px solid #e2e8f0; margin: 30px 0;">

  <p style="color: #718096; font-size: 14px;">
    Tento email byl odeslan automaticky. Neodpovidejte na nej.
  </p>
</body>
</html>

Dekujeme za Vasi zpravu!

Mily/a {{name}},

Dekujeme za vyplneni formulare. Vasi zpravu jsme obdrzeli a odpovime Vam do 24 hodin.

Shrnuti Vasi zpravy:
{{message}}

Pokud mate nalehavou otazku, kontaktujte nas na +420 777 123 456.

S pozdravem,
Vas tym

---
Tento email byl odeslan automaticky. Neodpovidejte na nej.

POST https://api.simplyforms.app/v1/forms/{FORM_ID}

{
  "success": true
}
// Submissions are relayed, never stored — there is no submissionId.
// It means the notification email was handed to the mail server. If that
// fails you get 502 DELIVERY_FAILED; past the monthly email limit and its
// grace allowance, 429 MONTHLY_EMAIL_LIMIT_REACHED (see below).

// Every error: "ok": false, "code" and "message" at the top level,
// sometimes extra fields (reset_date, errors, challenge_required, ...)
{
  "ok": false,
  "code": "DAILY_LIMIT_EXCEEDED",
  "message": "Daily submission limit exceeded.",
  "reset_date": "2026-10-06T00:00:00+00:00",
  "detail": {
    "ok": false,
    "code": "DAILY_LIMIT_EXCEEDED",
    "message": "Daily submission limit exceeded.",
    "reset_date": "2026-10-06T00:00:00+00:00"
  }
}
// "detail" repeats the same object for older clients and is deprecated.
// Codes: INVALID_FORM_ID_FORMAT, INVALID_FORM_ID (401), EMPTY_PAYLOAD,
// UNSUPPORTED_CONTENT_TYPE, INVALID_JSON, INVALID_PAYLOAD, INVALID_REQUEST (422),
// CAPTCHA codes (CAPTCHA_FAILED, ALTCHA_EXPIRED, ...), VALIDATION_FAILED,
// DOMAIN_LIMIT_EXCEEDED (403), FILE_SIZE_LIMIT_EXCEEDED, FILE_TOO_LARGE,
// PAYLOAD_TOO_LARGE (413), DAILY_LIMIT_EXCEEDED, MONTHLY_EMAIL_LIMIT_REACHED,
// RATE_LIMIT_EXCEEDED (429, Retry-After header), SUBMISSION_FAILED, INTERNAL_ERROR (500),
// DELIVERY_FAILED (502: the email could not be sent, try again)

// JavaScript: if (!response.ok) show(body.message), branch on body.code