Post the form to https://<your-site>/api/v1/marketing/submitform with fields txName, txLastName, txEmail, optional txPhone, and resellerId (the kitchen the contact belongs to). Sprwt adds the person to that kitchen's newsletter group - as an existing customer if the email matches an account, otherwise as a new marketing contact - and fires the User: New Newsletter trigger. Responses are JSON: {data:{status:true}} on success, or an error such as Please provide a valid name, Please provide a valid email, Invalid Reseller (unknown kitchen) or Invalid Group (the kitchen has no newsletter list configured). A companion GET /api/v1/marketing/captchatoken returns an image captcha to embed when Google reCAPTCHA is not configured.