Start

Signed, auditable contact form delivery

Signed contact forms to email

BitterPost receives contact form webhooks, verifies each submission, delivers a reply-ready email, and records the handoff so you can audit what happened.

HMAC verified Reject spoofed submissions before email is sent.
Reply-ready email Preserve the submitter as Reply-To when present.
Delivery log Keep status and provider IDs without storing rendered email bodies.

BitterPost is the smallest reliable handoff between a website form and a team inbox. Create an endpoint, sign each POST with the endpoint secret, and BitterPost turns the submitted fields into a readable email delivered through SendGrid.

The value is the signed handoff. A random actor cannot spoof your form endpoint, the Reply-To header can point at the submitter, and each delivery attempt keeps enough status to confirm whether the message reached the provider.

BitterPost is not a help desk, shared inbox, or CRM. Use BitterDesk when you need queues, assignments, statuses, and conversation history. Use BitterPost when the job is to get a signed contact form submission into email with an auditable delivery record.

Start with a checkout link

Enter the billing email, choose a plan, and BitterPost will open Stripe Checkout. The form sends only the email address and plan key.

How it works

1

Create an endpoint

Choose the recipient inbox and get a unique webhook URL.

2

Sign the POST

Send fields with an HMAC-SHA256 signature header.

3

Reply from email

Receive a formatted message and review delivery status.

Pricing

Starter
$9
/month
  • 5 endpoints
  • 500 deliveries/month
  • HMAC verification
  • Delivery logs
Enterprise
$99
/month
  • 500 endpoints
  • 50,000 deliveries/month
  • HMAC verification
  • Delivery logs

Frequently asked questions

How does HMAC verification work?

Each endpoint has a secret key. When you send a webhook, include an HMAC-SHA256 signature in the header. BitterPost verifies the signature before processing the payload, preventing unauthorized submissions.

Can I use BitterPost with a static website?

Yes. Static sites can post to a BitterPost endpoint as long as the submission is signed. A small serverless function or build-time integration can add the HMAC signature before the handoff.

How are emails formatted?

Each form field becomes a labeled row in the email body. The subject includes the endpoint name and timestamp. Reply-To is set to the submitter's email so you can respond directly.

How is BitterPost different from BitterDesk?

BitterPost verifies a form submission, sends one email, and logs the delivery handoff. BitterDesk is for managing support conversations after someone has written in.

What happens if email delivery fails?

BitterPost logs every delivery attempt with status. Failed deliveries are retried automatically. You can review delivery status in the dashboard or via the API.