How QuickMail + ColdRelay Work Together
ColdRelay (Infrastructure)
ColdRelay provides the mailboxes QuickMail sends from. Each mailbox is a Microsoft 365 account on a dedicated, isolated Azure tenant with its own dedicated IP, fully-automated DNS (SPF, DKIM, DMARC), and a 95% inbox-placement guarantee. ColdRelay's pricing is per-mailbox: $1 (1-199), $0.85 (200-999), $0.70 (1K-4,999), $0.55 (5K+). Setup completes in 60 minutes, no warmup wait.
QuickMail (Sending Platform)
QuickMail is one of the longest-running cold email and sales engagement platforms — agency-favorite, with sequences, multi-inbox campaign distribution, inbox rotation, an Auto-Warmer, and detailed analytics including reply rate and conversion tracking. QuickMail does NOT provide the underlying mailboxes or DNS. You bring your own mailboxes via SMTP/IMAP credentials, and QuickMail orchestrates campaigns across them.
Why use them together
QuickMail is the campaign engine (sequences, inbox rotation, Auto-Warmer, analytics). ColdRelay is the infrastructure beneath it (mailboxes, dedicated IPs, DNS). The combination keeps QuickMail's mature sales-engagement features on top of purpose-built cold email infrastructure. They're loosely coupled — if you ever switch sending platforms, the ColdRelay mailboxes keep working with any tool that supports custom SMTP/IMAP.
Connect QuickMail to ColdRelay (Step-by-Step)
- 1
Order ColdRelay mailboxes
Sign up at coldrelay.com/sign-up, pick a domain (ColdRelay handles registration for $14), and order your mailbox count. The minimum is 50 mailboxes ($50/month at the base tier). ColdRelay's automation provisions the dedicated mail server, registers the domain, and creates all mailboxes inside an isolated Azure tenant.
Note: Provisioning takes 60 minutes end-to-end. You'll receive a CSV with every mailbox's SMTP host, port, username, and password once it's complete.
- 2
Wait for DNS propagation
ColdRelay configures SPF, DKIM, and DMARC records automatically on the new domain. DNS propagation usually completes in under an hour but can take up to 24. You can verify with the Email Deliverability Test at coldrelay.com/tools/email-deliverability-test — when SPF, DKIM, DMARC, and MX all show as configured, you're ready.
Note: Don't connect mailboxes to QuickMail before all four records (SPF, DKIM, DMARC, MX) verify correctly. Sending before authentication is in place causes immediate spam-folder placement and can taint mailbox reputation from day one.
- 3
Connect mailboxes to QuickMail
In QuickMail, go to Settings → Inboxes → Add Inbox → Custom SMTP. For each ColdRelay mailbox, paste its SMTP host (box.YOURDOMAIN.com), SMTP port (587), SMTP username (the full email address), and the password from the ColdRelay CSV. Then add the IMAP server (same host) on port 993 with TLS. QuickMail tests the connection and marks the inbox as Connected once it validates both SMTP and IMAP.
Note: If QuickMail returns an authentication error during the test, verify you copied the password exactly from the CSV — Microsoft 365 app-style passwords are case-sensitive and can include characters that look similar (capital I vs lowercase l, zero vs O). Re-pasting from the CSV file rather than retyping fixes most connection failures.
- 4
Set daily send limits per inbox
In each QuickMail inbox's settings, set Daily Limit to 2 outbound emails per day. This matches ColdRelay's per-mailbox cap (designed for optimal deliverability, not maximum volume). With 50 mailboxes you can send 100 outbound emails/day; 200 mailboxes = 400/day; 1,000 mailboxes = 2,000/day. QuickMail respects each inbox's individual limit during campaign distribution.
Note: Going higher than 2/day/mailbox is the single fastest way to degrade deliverability. ColdRelay's pricing model assumes 2/day — if you need 5,000+ emails/day, add more mailboxes, don't push existing ones harder. The 95% inbox guarantee is contingent on respecting this cap.
- 5
Enable QuickMail Auto-Warmer
Turn on QuickMail's Auto-Warmer for each ColdRelay inbox under Settings → Inboxes → [Inbox] → Auto-Warmer. Set the daily warmup volume to 2 emails/day. Auto-Warmer exchanges emails with other QuickMail warmup-network inboxes, replies to a portion of them, and rescues messages from spam to build sender reputation organically.
Note: ColdRelay mailboxes ship reputation-ready — the dedicated Azure tenant and dedicated IP isolation give you a clean reputation baseline — but running Auto-Warmer alongside live campaigns for the first 2 weeks is still recommended. After that, you can leave it on at a low background level indefinitely.
- 6
Configure inbox rotation in your campaign
In QuickMail, create a campaign, then under Sending Inboxes select all the ColdRelay inboxes you want to distribute sends across. QuickMail's inbox rotation automatically spreads campaign sends evenly across every assigned inbox respecting each one's daily cap — a 400-prospect campaign across 200 ColdRelay inboxes will send ~2 emails from each inbox per day.
Note: Inbox rotation is one of QuickMail's strongest features for cold email. Use spintax variations on subject lines (the Spintax Generator at coldrelay.com/tools/spintax-generator generates the syntax) to avoid fingerprinting across rotated inboxes.
- 7
Build the sequence and launch
Add your prospect list (CSV upload or QuickMail's prospect database), write your sequence (initial email + follow-ups, typically 3-5 steps spaced 3-5 days apart), set send windows to your prospects' working hours, and launch. QuickMail's analytics dashboard tracks opens, replies, bounces, unsubscribes, and conversion events in real time.
Note: Validate every campaign against the CAN-SPAM Checker at coldrelay.com/tools/can-spam-checker before launch. The most common cause of post-authentication spam placement is campaign content (subject lines triggering filters, link density too high) — not the infrastructure.
- 8
Monitor deliverability ongoing
Run the Email Deliverability Test weekly to verify SPF/DKIM/DMARC stay passing. Check Google Postmaster Tools and Microsoft SNDS for spam-folder rates and IP reputation. ColdRelay automatically monitors blocklists — you'll get an alert if any of your dedicated IPs hit a major blocklist (Spamhaus, Barracuda, SORBS, SpamCop) so you can pause affected inboxes immediately.
Note: QuickMail's Inbox Health score is a useful at-a-glance signal. If any individual inbox's health drops, pause that inbox in QuickMail and run a deliverability test on its domain before resuming. ColdRelay's deliverability consultant (included at higher mailbox volumes) can help diagnose persistent issues.
Key Considerations for QuickMail + ColdRelay
Daily send limits per mailbox
Set QuickMail's per-inbox daily limit to 2 outbound + 2 warmup = 4 total/day MAX. This is ColdRelay's optimal-deliverability cap. Going higher is the single biggest cause of mailbox burnout we see across cold email tools. Scale total volume by adding more inboxes, not by pushing existing ones harder — QuickMail's inbox rotation makes scaling horizontally painless.
Dedicated IPs end shared-IP risk
Each ColdRelay mailbox is on a dedicated IP within your isolated Azure tenant. Other QuickMail users on shared sending infrastructure are sharing IP reputation with random other senders — one bad actor on the same IP damages everyone's deliverability. With ColdRelay your IP reputation is entirely your own, and QuickMail's analytics give you visibility into exactly how that reputation is performing.
QuickMail's inbox rotation pairs perfectly with multi-domain ColdRelay
ColdRelay caps each domain at 100-150 mailboxes for deliverability reasons, so larger operations span multiple domains. QuickMail's inbox rotation handles multi-domain campaigns natively — assign inboxes from each domain to different campaign tracks (or the same campaign) and QuickMail distributes sends evenly. This is one of the most cost-effective ways to scale cold email past 5,000 emails/day.
Auto-Warmer should not exceed the daily cap
QuickMail's Auto-Warmer counts against deliverability budget the same as outbound sends. Keep warmup at 2/day/inbox so total mailbox activity stays within the 4/day ceiling (2 outbound + 2 warmup). Cranking Auto-Warmer to high volumes thinking it accelerates reputation is a common mistake that backfires.
Switching cost is low
If you decide QuickMail isn't right and want to move to Instantly, Smartlead, or another platform later, your ColdRelay mailboxes work with any tool that supports custom SMTP/IMAP. You don't lose the infrastructure investment — only the sequence configuration needs to migrate. ColdRelay deliberately stays vendor-neutral on the sender layer.
Reply handling and unified inbox
QuickMail polls each inbox's IMAP at port 993 and surfaces replies in its unified inbox view. ColdRelay's IMAP setup is standard — no special configuration needed. QuickMail can also classify replies as positive/negative/neutral automatically, which is useful for routing genuine interest to a human while keeping out-of-office and unsubscribes out of the way.
Pricing Snapshot
ColdRelay
ColdRelay's per-mailbox cost ranges from $1.00 (1-199 mailboxes) down to $0.55 (5,000+). Domain registration is $14/year, one-time. For 200 mailboxes: 200 × $0.85 = $170/month + $14 annual domain cost. The 50-mailbox minimum starts at $50/month.
QuickMail
QuickMail's pricing is tier-based on inbox count and feature access. The Basic plan starts around $49/month with a small inbox count and core sequencing. The Pro plan is around $89/month and unlocks more inboxes, advanced analytics, and Auto-Warmer at scale. The Expert plan around $129/month is for agency-scale operations with the highest inbox counts and full feature access. Exact pricing and inbox limits should be confirmed at quickmail.com.
Total monthly
A typical 200-mailbox cold email operation: ColdRelay infrastructure at ~$170/month + QuickMail Pro at ~$89/month = ~$259/month total. At 1,000 mailboxes: ColdRelay $700/month + QuickMail Expert at ~$129/month = ~$829/month. Compare against Google Workspace at $6+/mailbox/month: 200 GW mailboxes alone would be $1,200/month before QuickMail's platform cost — and you'd still be sharing reputation risk with the rest of GW's cold email senders.
Common Issues + Fixes
⚠ QuickMail returns authentication failed when adding a ColdRelay inbox
Verify the SMTP credentials match the ColdRelay CSV exactly — password fields are case-sensitive and can contain characters that look similar (capital I vs lowercase l, O vs 0). Copy directly from the CSV rather than retyping. Confirm SMTP host is box.YOURDOMAIN.com (not the bare domain), port is 587, and security is STARTTLS. If still failing, the mailbox provisioning may not be fully complete yet — wait the full 60-minute window before connecting.
⚠ Auto-Warmer enabled but reputation not improving
Confirm Auto-Warmer is actually running by checking the Auto-Warmer activity log in QuickMail. If activity shows zero sends, the inbox may have hit a soft-fail during a warmup attempt — most commonly because DNS hadn't fully propagated when warmup started. Re-test the domain with the Email Deliverability Test, confirm SPF/DKIM/DMARC pass, and restart Auto-Warmer. Also confirm the daily warmup volume is set to 2 (not 0 — a common oversight).
⚠ Emails landing in spam at Gmail or Outlook
Run the Email Deliverability Test against the domain. If SPF, DKIM, or DMARC fails, the records may not have fully propagated — wait 24 hours and re-test. If all three pass, the cause is almost always content: subject lines triggering spam filters, link density too high, sender display names that look off, or exceeding the 2/day/inbox cap. Use the CAN-SPAM Checker and Subject Line Generator at coldrelay.com/tools to validate campaign content before resuming sends.
⚠ Inbox rotation appears unbalanced — some inboxes sending far more than others
Check that every assigned inbox has the same Daily Limit (2) and is in Connected status. If one inbox has a higher cap, QuickMail will favor it during rotation. If one is disconnected or paused, it gets skipped and the others absorb its share. Standardizing every ColdRelay inbox at the same 2/day limit makes rotation perfectly even.
⚠ Replies not appearing in QuickMail's unified inbox
QuickMail polls IMAP on port 993 with TLS. Re-test the IMAP credentials in Settings → Inboxes → [Inbox] → Test Connection. Most commonly the IMAP password matches the SMTP password but it can drift if a mailbox was reset on the ColdRelay side. Re-pull the credentials from your most recent ColdRelay mailbox CSV and re-enter them. If replies still don't appear, check the affected mailbox directly via webmail to confirm replies are actually arriving at the mailbox level.
Frequently Asked Questions
Do I need ColdRelay if I already have QuickMail?
QuickMail is a campaign engine — it doesn't provide mailboxes or DNS. You need an infrastructure provider (ColdRelay, Google Workspace, etc.) underneath it. Most QuickMail users start with Google Workspace mailboxes at $6+/mailbox/month and switch to ColdRelay because the infrastructure is purpose-built for cold email at a fraction of the cost ($0.55-$1.00/mailbox) with dedicated IPs and an isolated Azure tenant per customer.
Is ColdRelay better than Google Workspace for use with QuickMail?
For cold email at any scale beyond a handful of mailboxes: yes. Google Workspace charges $6+/mailbox/month and shares some risk across all GW senders. ColdRelay charges $0.55-$1.00/mailbox/month, gives each customer a dedicated Azure tenant with dedicated IPs, and bakes SPF/DKIM/DMARC automation into provisioning. The infrastructure quality is closer to enterprise-grade at indie-tool prices, and QuickMail's inbox rotation makes scaling across many ColdRelay mailboxes effortless.
How many mailboxes do I need to scale to my target send volume?
ColdRelay's per-mailbox cap is 2 outbound emails/day for optimal deliverability. So if you want to send 1,000 emails/day, you need 500 mailboxes. The Mailbox Calculator at coldrelay.com/tools/mailbox-calculator lets you input your target volume and gives you the exact mailbox count + pricing tier. QuickMail's inbox rotation handles the distribution automatically once the mailboxes are connected.
Can I use ColdRelay with QuickMail's Basic plan?
Yes, but the Basic plan caps inbox count at a number that won't make sense for scaled cold email. ColdRelay's minimum is 50 mailboxes, which means QuickMail Pro or Expert is the practical pairing. Confirm current inbox limits at quickmail.com — the platform tier needs to support at least the same number of inboxes as your ColdRelay order.
Will my QuickMail campaigns break if I switch to ColdRelay from another provider?
No. Switching infrastructure providers mid-campaign requires reconnecting each inbox in QuickMail (new SMTP/IMAP credentials), but campaign logic, sequences, prospect lists, and analytics history all stay intact. The transition takes a few minutes per inbox. We recommend pausing campaigns during the swap to avoid any deliverability blips, then resuming once every inbox shows Connected status with the new ColdRelay credentials.
Does QuickMail's Auto-Warmer conflict with ColdRelay's setup?
No, they complement each other. ColdRelay provides reputation-clean mailboxes (dedicated Azure tenant, dedicated IPs, fully-configured authentication on day one) and QuickMail's Auto-Warmer maintains that reputation through ongoing organic activity. Keep warmup at 2/day/inbox so total daily activity stays at the 4/day ceiling (2 outbound + 2 warmup). Running Auto-Warmer alongside live sends for the first 2 weeks is recommended.
What if QuickMail's deliverability is bad with my ColdRelay mailboxes?
That's almost always a campaign-content issue (subject lines triggering spam filters, link density too high, sender names looking off) rather than an infrastructure issue. ColdRelay's 95% inbox guarantee means the infrastructure is doing its job. Use the CAN-SPAM Checker at coldrelay.com/tools/can-spam-checker, the Subject Line Generator, and the Email Deliverability Test to validate every campaign before launch. ColdRelay's deliverability consultant (included at higher volumes) can help diagnose persistent issues.