Add a client, verify their domain, warm a dedicated IP, and start sending transactional and broadcast email in minutes. No shared sender pool, no per-contact surprises, no reselling someone else's SES account.
Dozens of clients, dozens of domains, one console. Each client isolated from the next, so one sender's mistake never drags down another's inbox placement.
Every client sends from their own verified domain on their own dedicated IP. A high-complaint launch from Client A can never touch the deliverability of Client B. No noisy-neighbor pool.
Add a domain and mailstein generates SPF, DKIM, and DMARC records automatically. Dedicated IPs come with managed warm-up, so new client sending ramps on a proper schedule instead of getting throttled on day one.
Message logs, bounces, complaints, opens, and suppressions are scoped per domain. Pull the delivery record for a single client when they ask "did it send?" without digging through everyone else's traffic.
mailstein charges per email sent — transactional and broadcast on the same meter. Onboarding a client with a 200k-contact newsletter doesn't spike your bill just for storing the list. You pay when mail actually goes out.
Aggregate sending rolls up into one predictable plan — roughly $130 at 125K sends/month, $520 at 700K. Forecast a retainer's email cost from a single number instead of reconciling per-client contact counts every month.
Transactional receipts, password resets, and product email sit next to campaigns, audiences, and broadcasts — same platform, same logs, scoped per client domain.
Programmatically manage domains, contacts, campaigns, webhooks, and suppressions across your whole client roster. REST API, SMTP, plus SDK, CLI, and MCP so your agent workflows and automations can provision and send without leaving your stack.
The honest version. Tools like Resend and Postmark are genuinely good products with polished DX — but the sending infrastructure and the IP reputation aren't yours, and the billing wasn't designed for a portfolio of clients.
| mailstein | SES-backed platforms | |
|---|---|---|
| Dedicated IP per client | Yes, with managed warm-up | Shared pool or paid add-on |
| You own the sending IP & reputation | Yes | No — lives on their infra |
| Message logs on infrastructure you control | Yes | No |
| Transactional + broadcast, one meter | Yes | Often separate products |
| Billed per send, not per contact | Yes | Marketing often per contact |
| Auto SPF / DKIM / DMARC per domain | Yes | Usually yes |
| SDK / CLI / MCP for agent workflows | Yes | Partial |
Free plan: 50 emails a month and one domain, no card. Verify a client, warm an IP, and see the deliverability difference before you migrate a thing.
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