A website enquiry that leaves a verifiable receipt.

Baseline: submission was not a receipt.

Before 17 September 2026, the website contact form prepared a message in the visitor’s email application. Marsen could not confirm from the website that the message was sent, accepted or recorded in the CRM. There was no stable reference for reconciling a retry.

Scope: validate, deliver, deduplicate and record.

Marsen added a same-origin Vercel endpoint, bounded field and campaign validation, a honeypot, privacy acknowledgement, a private n8n webhook and a Twenty CRM task. A UUID reference follows the request. The workflow checks for that reference before creating a task, so a repeated delivery can return an acknowledgement without creating another record.

• Only the production Marsen origin can submit to the public endpoint.
• The private webhook URL stays in managed environment configuration.
• The CRM record retains the reference, received time, contact details, landing page, broad source and request.
• The public response confirms acceptance without exposing the CRM task identifier.

Production test: one request, one replay, one CRM task.

The production test used one synthetic enquiry reference on 17 September 2026. The first request returned HTTP 202 with accepted true and duplicate false. An identical replay returned HTTP 202 with duplicate true. Direct database verification found exactly one TODO task containing the expected /contact landing page and google source. A request from an unapproved origin returned HTTP 403.

• Unique synthetic enquiries: 1
• Identical replay attempts: 1
• CRM tasks after both accepted requests: 1
• Cross-origin rejection attempts: 1

Checks and error handling.

Twenty-three automated checks passed across contact delivery, attribution and first-party measurement. The contact-specific checks cover normalization, invalid required fields, unsafe website protocols, the honeypot, production-origin enforcement and upstream acknowledgement. Local measurement checks cover unsupported events, private-looking paths, missing references, bots and sanitized forwarding. The production test directly confirmed origin rejection and CRM deduplication; it did not exercise every failure in production.

Review effort and operating cost.

The accepted enquiry creates a CRM task with TODO status and a next-day due date. A person still reviews the request, decides whether and how to reply, and closes or updates the task. The pilot used Marsen’s existing Vercel, n8n, PostgreSQL and Twenty infrastructure. No incremental platform price, staff time saving or payback period was measured, so this case makes no cost-saving claim.

Outcome and limits.

The tested workflow produced a durable, deduplicated CRM receipt for the synthetic request and gave the browser a confirmed acknowledgement. The sample is an implementation acceptance test, not evidence of conversion lift, response-time improvement, revenue impact or customer demand. Provider-confirmed Calendly booking attribution and a larger operating sample remain separate follow-up work.