Warmed by relationships you have never used
Every warmup-enabled inbox joins one shared mesh of real customer inboxes. Each send is a directed pair chosen for freshness, receivers are protected by their own ramp, and the reporting is denominated in mail that actually arrived.
Exact-pair freshness
Allocation prefers sender-to-recipient pairs that have never exchanged mail, then the least recently used, and never repeats a pair within a sender's day.
Receivers ramp on their own clock
A new inbox accepts five warmup messages a day, five more each day, up to sixty, paced at a steady jittered interval that is independent of what it sends.
Reporting you can act on
Placement per provider, sent versus arrived, and a clear line between provider lag and mail that never showed up.
A mesh of real inboxes, allocated for freshness
Shared warmup networks are a finite pool that every customer draws from, and most vendors describe them by who is allowed in. Scheduler Zero describes how pairs are chosen: the allocation history is the directed sender-inbox to recipient-address relationship, never-used pairs come first, then the least recently used, and the same pair never starts twice in one sender-local day. When no safe pair exists the sender underfills for the day.
- Every active warmup-enabled inbox is enrolled in the shared pool
- Never-used directed pairs first, least-recently-used second
- No pair repeats inside a sender's local day
- Short liquidity means fewer sends, never recycled pairs
Receiver protection is independent of the sending target
An inbox that has just joined should not absorb a mature sender's volume. Inbound warmup capacity starts at five messages per local day, grows by five each day, and caps at sixty. It is paced continuously at a stable jittered interval and shared by new threads, replies, and follow-ups, so a receiver never sees a burst at midnight or a flood from one enthusiastic peer.
- Inbound capacity ramps 5, 10, 15 up to 60 per local day
- Capacity is reserved before a send and released only on proven failure
- Replies and follow-ups draw from the same receiver budget
- Outbound slots are placed at stable jittered points in the sending window
Per-inbox limits, ramps, and recovery
Warmup and campaign sends share the inbox's physical pacing but keep separate budgets. Each inbox has its own daily cap, sending window, and ramp, and health-triggered recovery workflows can pause a sender and bring it back once it recovers. Warmup copy comes from a reviewed corpus with deterministic variation; no live warmup send depends on a model call.
- Daily warmup limit up to 50, with a per-inbox ramp
- Independent campaign and warmup budgets on shared pacing
- Recovery workflows pause and resume senders on health signals
- Subjects and bodies from a reviewed corpus, never generated at send time
Frequently asked questions
Ready to see it in action?
Join the private alpha and run a sequence whose replies are followed up by email, phone, and SMS from one lead record.