White Label Email API
Send email as
your customers
The email API built for SaaS platforms. Add white label email to your product in days, not months — with multi-tenant architecture, per-tenant analytics, and guided domain onboarding.
import Ark from "ark-email";
const client = new Ark({
apiKey: process.env["ARK_API_KEY"],
});
await client.emails.send({
from: "[email protected]",
to: ["[email protected]"],
subject: "Invoice #1042",
html: "<h1>Your invoice is ready</h1>",
tag: "invoices",
});Built for platforms where your customers send email
If your SaaS product sends email on behalf of customers — and those emails need to come from their domains, not yours — Ark is built for you.
CRMs
Let your users send from their own domain — proposals, follow-ups, and automations all branded to their business.
Helpdesks
Ticket notifications, CSAT surveys, and agent replies that come from your customer's support domain, not yours.
Invoicing
Payment reminders, receipts, and statements sent from your customer's billing domain with full authentication.
Scheduling
Booking confirmations, reminders, and cancellations from your customer's brand — not a generic noreply address.
Multi-tenant from the ground up
Every API call is scoped to a tenant. Domains, suppression lists, analytics, and webhook events are all isolated per tenant.
Learn more about multi-tenant email, email API, or read our guide on sending email from your customer's domain
Multi-tenant email features, built in
Features built for the unique challenges of sending email on behalf of your customers.
Domain Onboarding
Your customers add their domain; Ark detects their DNS provider, generates records, and verifies automatically. No support tickets.
Learn morePer-Tenant Webhooks
Get delivery events scoped by tenant — so you can build real-time email notifications into your product.
Learn moreTenant Management
Create, configure, and monitor tenants via REST API. The Platform → Tenants → Domains hierarchy matches how your product already works.
Learn moreUsage & Billing
Track exactly how many emails each tenant sends. Pull usage into your billing system with export and timeseries endpoints.
Learn moreWhite Label Analytics
Show your customers their email performance. Deliveries, opens, clicks, and bounces — all scoped per tenant.
Learn moreAPI-first, tenant-aware
Every endpoint is scoped by tenant. Create tenants, add domains, send email, and pull analytics — all through a REST API designed for multi-tenant platforms.
// 1. Create a tenant
const tenant = await client.tenants.create({
name: "Acme Corp",
});
// 2. Add their sending domain
const domain = await client.tenants.domains.create(
tenant.id,
{ domain: "acme.com" }
);
// 3. Send email as the tenant
await client.emails.send({
from: "[email protected]",
to: ["[email protected]"],
subject: "Welcome to Acme",
html: "<h1>You're in!</h1>",
});DIY vs. generic APIs vs. Ark
You could build multi-tenant email yourself, or bolt it onto a generic API. Or you could use the one built for it.
| Feature | Build it yourself | SendGrid / Mailgun | Ark |
|---|---|---|---|
| Multi-tenant architecture | Partial | ||
| Per-tenant domain isolation | Manual | ||
| Guided DNS onboarding | |||
| Per-tenant suppression lists | Manual | ||
| Per-tenant analytics | Partial | ||
| Per-tenant webhook events | Partial | ||
| Per-tenant usage metering | |||
| Time to production | Months | Weeks | Days |
See detailed comparisons: vs. SendGrid · vs. Mailgun · vs. Resend
Frequently asked questions
Stop building email infrastructure
Create your first tenant, add their domain, and send your first email — most platforms do it in under an hour.
Free plan available · No credit card required