Contacts & Segments

One contact database for every email you send

Transactional and marketing sends share the same contacts, properties and suppression list — so a bounce or unsubscribe in one place protects your sender reputation everywhere.

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How it works

1
Import or sync
Upload a CSV, sync via API, or let contacts appear automatically from transactional sends.
2
Add custom properties
Store plan, signup date, lifecycle stage — anything you want to filter or personalize on.
3
Build lists and segments
Group contacts manually into lists, or define live segments from property and event filters.
4
Reuse everywhere
The same contact and segment power campaigns, automations and personalized transactional sends.

upsert-contact.sh

# Create or update a contact
curl -X POST https://api.mailcraft.host/v1/contacts \
  -H "Authorization: Bearer sk_live_••••••••" \
  -H "Content-Type: application/json" \
  -d '{
    "email": "[email protected]",
    "first_name": "Jamie",
    "properties": { "plan": "pro", "signed_up_at": "2026-09-01" }
  }'

Shared by transactional and marketing Typed custom properties Live segments Global suppression list

One source of truth

Every send works from the same contacts

Properties, lists and suppressions are shared everywhere, so a bounce or unsubscribe in one place protects you in all of them.

Upsert by email

One call creates or updates a contact, merging properties and validating them against their registered types.

Segments that stay current

Filter on properties, status or list membership — segments recount as your contacts change.

Powers everything else

The same contacts and segments drive campaigns, automations and personalised transactional email.

What's included

Everything in Contacts

Live on your account the moment you sign up — nothing to request or provision.

Unlimited contacts on every plan — pricing scales with volume, not list size

Unlimited custom properties per contact

Dynamic segments from properties, tags, lists or engagement

Global suppression list shared across transactional and marketing

CSV import/export and a full contacts API

Full activity timeline per contact — sends, opens, clicks, events

Pairs well with the rest of MailCraft

Contacts is one piece of the stack — reach for these when you need more.

Email Validation

Catch typos, dead domains and disposable inboxes before they cost you reputation.

Learn more

Email API

Send transactional email over a clean REST API with SDKs for ten languages.

Learn more

SMTP Relay

Point any existing mailer at MailCraft and keep every line of code you already wrote.

Learn more

Ready to try Contacts?

Create a free account and send your first email — through the API, SMTP, or an MCP-connected AI agent — in minutes. No credit card required.

Start building for free