Send unlimited cold email that reaches the inbox
SpamCipher is the cold email platform for unlimited, fully automated outbound. We spread every campaign across warmed domains and mailboxes, hold each one inside a safe daily limit, and throttle anything that drifts. It is why we are the only platform that can promise you 90%+ inbox placement.
Start sending free
Part of the SpamCipher cold email platform: unlimited, fully automated cold email on one owned pipeline, and the only platform that can promise you 90%+ inbox placement because we measure it.
Cold email sending, built on real deliverability
Most tools bolt sending onto a warm-up pool and hope. SpamCipher runs the pipeline that decides whether mail lands, then sends on top of it. You never send from your primary domain, and no mailbox goes live until it is authenticated and warmed.
- Get sending domains and mailboxes. Add secondary, lookalike domains and mailboxes, never your primary domain, so your main brand stays protected.
- Authenticate every domain. SPF, DKIM, and DMARC are set up and verified so inbox providers trust the sender from the first send.
- Warm on a real seed network. Each mailbox ramps gradually on a live seed network, roughly 10-50 a day, until it has the reputation to send at volume.
- Send, measured and throttled. Campaigns rotate across warmed mailboxes at human-like, business-hours pacing while placement is measured continuously.
- Safe per-mailbox limits: each mailbox stays inside a conservative daily cap
- Automatic throttling: pacing tightens the moment a mailbox looks at risk
- Complaint and bounce guardrails: spam stays under 0.3% and bounces under 2%
- Auto-pause: any mailbox that crosses a line is paused within one monitoring cycle
- Measured placement: seed tests show exactly where your mail lands
Cold email sending, from zero to volume
Connect or provision mailboxes, warm them, and let campaigns send themselves across the whole fleet.
Add sending mailboxes
Bring your own secondary domains and mailboxes, or let SpamCipher provision them for you, isolated per customer.
Warm on the seed network
Each mailbox ramps gradually, roughly 10-50 a day, on a live seed network until it earns real sending reputation.
Send at unlimited volume
Automatic inbox rotation spreads campaigns across every warmed mailbox at safe, throttled pacing, so total volume scales without burning any single inbox.
Scale outbound without torching your reputation
Start sending cold email that is measured, throttled, and built to land.
Automatic inbox rotation across many mailboxes
Unlimited does not mean firing thousands of emails from a single mailbox. That is exactly how domains get burned. SpamCipher gets its volume from automatic inbox rotation: every campaign is spread across many warmed domains and mailboxes, multi-mailbox sending where each inbox sends a small, human-like number of messages per day.
Every mailbox stays inside a safe daily limit, and automatic throttling steps in the instant one crosses a complaint or bounce line, holding spam under 0.3% and bounces under 2%. The more warmed mailboxes you add, the more you can send, with none of them ever at risk. See how to scale cold email without torching your reputation.
Bring your own, or let us build it
Already have secondary domains and mailboxes? Connect them and SpamCipher warms, monitors, and sends across all of them.
Starting fresh? Let SpamCipher provision the domains, mailboxes, authentication, and warm-up for you, isolated per customer so no one else's sending can touch your reputation.
Either way you land on the same owned pipeline, with per-mailbox limits and automatic throttling built in from the first send. Pair it with automations to run the whole sequence hands-off.
Set up sendingWhy we can promise 90%+ inbox placement
Other platforms guess at deliverability from a synthetic warm-up pool that Gmail and Microsoft increasingly detect. SpamCipher measures it. Seed-based inbox placement testing sends to real seed accounts across the major providers and shows exactly where your mail lands, inbox, promotions, or spam, per sending mailbox.
That live measurement is what lets us stand behind 90%+ placement instead of hoping for it. When a mailbox starts sliding toward spam, we see it in the seed results and auto-pause it before it burns your domain. Learn the fundamentals in our guide on how to send cold email, and the current cold email sending limits for 2026.
