Send Millions.
Catch Every Reply.
The only cold email sequencer with full reply handling on SuperSend Relay. One API key powers thousands of senders — every prospect reply is caught, threaded, and managed in a unified inbox.
SuperSend Relay
The High-Volume Sender’s Dilemma
If you’re sending 300k+ emails per month, every option on the market breaks in a different way.
Mailboxes Don't Scale
Buying 500 Google Workspace accounts to send 1M emails is expensive, takes months of warm-up, and Google actively fights this use case.
APIs Can't Handle Replies
Transactional senders like SendGrid and Mailgun can blast millions of emails, but they're one-way. When a prospect replies, there's no inbox to catch it.
Sequencers Assume Small Scale
Every outbound sequencer — Apollo, Instantly, Smartlead — is built around individual Google/Outlook accounts. They have no concept of a transactional API backend.
SuperSend Relay solves all three. Volume of dedicated infrastructure. Experience of individual mailboxes. Every reply caught.
How It Works
From onboarding call to millions of emails in four steps. No mailboxes to buy, no third-party accounts to set up.
Onboarding Call with SuperSend
SuperSend Relay is an enterprise product. We get on a call, scope your volume, and provision your dedicated infrastructure — IPs, warm-up schedule, and domain authentication — all set up by our team.
Create Sending Identities
Build hundreds or thousands of unique senders on top of your Relay infrastructure. Each gets its own email, display name, daily limits, and campaign assignments. Bulk import via CSV.
Emails Go Out via Dedicated IPs
Campaign emails route through SuperSend Relay's dedicated IP infrastructure with automated warm-up. Threading headers are added for proper conversation continuity.
Every Reply Lands in Your Inbox
Replies route through SuperSend's mail server via MX records, match to the original outbound via threading headers, and appear in the unified inbox — fully threaded and AI-categorized.
Two Paths, One Inbox
Outbound emails go through SuperSend Relay’s dedicated infrastructure. Replies route back through SuperSend’s mail server. Both meet in the unified inbox.
Outbound Path
Sending via SuperSend Relay
Reply Path
Replies routed through SuperSend
Built for Scale, Down to the Details
Send-As Architecture
One API key powers thousands of unique sending identities. Each has its own email, name, limits, and history. Zero marginal cost per sender.
Automated DNS Setup
SPF, DKIM, DMARC, Return Path, and MX records — all configured automatically when you purchase domains through SuperSend.
Intelligent Rate Limiting
Redis-backed rate limiting ensures you never exceed infrastructure limits. Automatically throttles and resets every 60 seconds.
Conversation Threading
In-Reply-To, References, and Thread-ID headers match every reply to the original outbound. Full conversation history preserved.
AI Reply Categorization
Every reply is auto-classified: interested, meeting request, not interested, out-of-office, unsubscribe. Contact status updates automatically.
Domain Health Monitoring
SPF, DKIM, DMARC, MX, and blacklist status tracked per domain. One-click fix guidance when something needs attention.
What No Other Tool Can Do
Traditional sequencers cap at mailbox scale. Transactional APIs can’t handle replies. SuperSend Relay does both.
| Capability | SuperSend+ SuperSend Relay | Traditional SequencersApollo, Instantly, etc. | Transactional APIsSendGrid, Mailgun |
|---|---|---|---|
| Send millions per month | |||
| Multi-mailbox experience | |||
| Unified inbox with replies | |||
| Conversation threading | |||
| No mailbox purchasing needed | |||
| Dedicated IP infrastructure | |||
| Automated IP warm-up | |||
| Campaign sequences | |||
| AI reply categorization |
SuperSend Relay — Built-In High-Volume Infrastructure
SendGrid, Mailgun, and Amazon SES explicitly prohibit cold email and will shut you down. SuperSend Relay is our purpose-built high-volume cold email infrastructure — dedicated IPs, automated warm-up, and full domain management, all managed by SuperSend. No third-party accounts. No API keys to configure. We set everything up — book a call to get started.
SuperSend Relay handles the infrastructure. SuperSend handles the sequencing, reply handling, conversation threading, and unified inbox. It’s one product — the complete high-volume cold email stack.
Talk to us about high-volume sendingWhat SuperSend Relay Includes
Not at high volume yet? SuperSend grows with you.
SuperSend also supports Google Workspace, Microsoft Outlook, and standard SMTP. Start with traditional mailboxes and scale into SuperSend Relay when your volume demands dedicated infrastructure. Same platform, same inbox, same workflows — just a different backend.
Deep reads
Related guides on outbound infrastructure, deliverability, and sequences.
FAQs
Common questions about SuperSend Relay and high-volume sending.
See High-Volume Sending in Action
Book a demo to see how SuperSend powers thousands of senders on SuperSend Relay with full reply handling from a single API key.
Join 500+ teams sending with SuperSend