Feature 01 — Clean Pool
A network you can actually trust.
Most warmup networks are open registration. Anyone can join. That means you're swapping emails with spammers, burned domains, and cheap SMTP resellers. SimplyWarmup is the opposite.
Why open-access warmup networks fail you.
Google, Yahoo, and Microsoft have spent billions building reputation systems. They know exactly how warmup traffic looks.
Guilt by Association
When your domain swaps emails with a known spammer in a shared pool, ESPs see that. The spammer's toxic reputation rubs off on you. Your health score drops before you send a single real campaign email.
Static Footprints
Legacy networks send static, repetitive emails ("Thanks, got it!") which modern ML-based spam detection identifies in milliseconds. The entire pool gets flagged as mechanical — including your inbox.
No Real ESP Trust
Custom SMTP domains have zero domain age, zero sending history, and zero organisational identity. They provide no trust signal to Google or Microsoft. Real Workspace/M365 accounts do.
How the Clean Pool works.
Admission is strict, monitoring is continuous, and ejection is instant.
Provider Acceptance Gate
Every inbox connecting to SimplyWarmup is validated against our provider blocklist at the OAuth handshake stage. We accept only Google Workspace and Microsoft 365 accounts. Consumer domains (@gmail.com, @outlook.com, @yahoo.com) and low-reputation custom SMTP hosts are blocked at the connection layer — they never enter the pool.
Continuous Health Scoring
Our IInboxHealthService runs a numerical health algorithm against every active node. Scores are computed from send volume, spam event frequency, rescue counts, inbox placement rates, and inactivity penalties. A healthy node maintains a score above 90. Nodes dipping below the threshold are automatically paused from pool participation until recovery is confirmed.
Instant Toxic Node Ejection
When a node reaches critical health indicators — persistent spam placement, blacklist signals, or repeated recovery failures — it is instantly ejected from the pool. No grace periods. The rest of the network never exchanges another email with that domain. Your inbox health score is completely isolated from that node's trajectory.
Smart Pacing Protects the Pool
New inboxes ramp gradually — starting at 2 emails/day and increasing by 2 per day up to a 40/day cap. This gradual ramp mirrors the natural inbox establishment pattern and protects the pool from sudden volume spikes that would trigger ESP rate-limiting across the whole network.
FAQ
Common questions about the Clean Pool
What makes a warmup pool "clean" compared to other networks?
A clean warmup pool consists exclusively of verified real Google Workspace and Microsoft 365 accounts. Unlike open-access networks that accept any inbox to inflate their numbers, a clean pool enforces strict provider rules — no consumer addresses, no generic SMTP domains, and automated ejection of any node showing signs of spam behaviour. Engagement signals from verified corporate domains carry genuine weight with ESPs.
Does the quality of the warmup network actually affect my sender reputation?
Yes — significantly. Google and Microsoft treat engagement with spam-adjacent domains as a negative signal. Industry data shows inboxes using trusted real-inbox pools reach stable inbox placement faster than those using generic SMTP networks. Quality of engagement matters more than volume: opens and replies from corporate Google/Microsoft accounts signal to ESPs that real business contacts want your email.
How can I tell if my current warmup tool is using a toxic pool?
Warning signs include: warmup email engagement arriving within seconds of sending (real human replies don't arrive that fast), all warmup emails coming from similar-looking generic or custom SMTP domains, and your domain reputation in Google Postmaster Tools staying flat or declining despite weeks of warmup activity. If you see these patterns, your tool's pool may be generating negative signals rather than positive ones.
Should I stop warmup after my inbox is fully warmed?
No. Inboxes that maintain blended warmup alongside cold sends retain 8% higher inbox placement over 90 days compared to those that stop warmup entirely. Cold outreach typically generates 1–5% reply rates; warmup generates 30–35%. Keeping warmup at maintenance level (2–5 emails/day) keeps your engagement averages in the range that spam filters reward, offsetting the lower reply rates of prospecting.
Google Postmaster: Maintain spam rates below 0.1% to avoid deliverability penalties. Warmup pools using verified Google Workspace and Microsoft 365 accounts generate engagement that directly builds the reputation signals Postmaster Tools measures.