Developer-first email infrastructure

Email infrastructure
for developers

Receive emails via SMTP, authenticate with SPF/DKIM/DMARC, and deliver to your webhooks in real-time. No complex setup required.

Receive
Authenticate
Store
Deliver

How your emails flow through Unbo

From reception to delivery, every step is authenticated and verified.

Email Arrives

SMTP server receives incoming mail on your custom domain

Authentication Checks

SPF, DKIM, and DMARC verification runs automatically

Email Stored

Message is persisted with full headers and metadata

Webhook Fires

Parsed payload is delivered to your endpoint in real-time

Everything you need for email ingestion

Production-ready features built for developers who need reliable email infrastructure.

Email Receiving via SMTP

Custom domain email reception with full header parsing and attachment handling.

SPF/DKIM/DMARC

Built-in email authentication checks on every incoming message.

Webhook Delivery

Real-time HTTP delivery to your endpoints with structured JSON payloads.

Domain Verification

Simple TXT record verification to prove domain ownership.

Inbox Management

Multiple inboxes per domain with independent webhook configurations.

MCP Interface

AI-native email access via OAuth2-secured Model Context Protocol.

Webhook Signing

HMAC-SHA256 payload signatures for tamper-proof delivery verification.

Webhook Replay

One-click re-delivery of failed webhooks with full request logging.

Get started in three steps

From signup to receiving your first email in minutes.

1

Register your domain

Add your domain and verify ownership by adding a simple DNS TXT record.

2

Create inboxes & configure webhooks

Set up one or more inboxes and point them to your HTTP endpoints.

3

Start receiving emails

Unbo authenticates every email and delivers the parsed payload to your webhook in real-time.

Built for developers

Clean JSON payloads, HMAC-SHA256 signing, and AI-native access via MCP.

Webhook Payload Structure

Every email is delivered as a structured JSON payload to your endpoint, signed with HMAC-SHA256 for security.

{
  "from": "sender@example.com",
  "to": ["inbox@yourdomain.com"],
  "subject": "New order received",
  "text_body": "...",
  "html_body": "...",
  "spf": "pass",
  "dkim": "pass",
  "dmarc": "pass"
}

HMAC-SHA256 Signing

Every webhook delivery includes a signature header so you can verify payloads are authentic and untampered.

MCP Interface

Access emails programmatically through the Model Context Protocol with OAuth2 authentication for AI agents.

Webhook Replay

Failed deliveries can be replayed with a single click. Full request/response logging for debugging.

Beta

Free while we're in Beta

Unbo is in active development. During the Beta phase there's no charge — use every feature for free while we build toward general availability.

Beta Access

$0 / month

No credit card, no commitment. We'll give you plenty of notice before any paid plans launch.

  • All features unlocked during Beta
  • Custom domains & unlimited inboxes
  • Webhook delivery with signing & replay
  • MCP interface for AI agents
Get Started Free

Start receiving emails in minutes

Set up your domain, create an inbox, and start receiving authenticated emails delivered to your webhook.

Create Free Account
No credit card required Free tier included Setup in under 5 minutes