Email warmup

Email warmup gives a new or quiet mailbox a controlled history before it carries meaningful campaign volume. Norbelys gradually exchanges messages with healthy mailboxes in its warmup network, continues short reply threads, measures delivery, and slows down when a mailbox cannot safely accept more work. Warmup is included with every Norbelys plan. It is a reputation-building control, not a promise that every future message will reach the Primary inbox.

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Start warmup

1. Open Senders and select the mailbox.
2. Open its Warmup tab.
3. Turn on Warm up this mailbox.

Norbelys indexes an eligible sender when it is connected. Turning on warmup makes it available for a cohort; it does not expose credentials or campaign content to other participants.

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How the Smart Planner works

Warmup is organized into small cohorts rather than a single random pool. A cohort normally contains eight active mailboxes, with a minimum of four and a maximum of ten. Every member must use a different registrable domain. The matching rules are intentionally strict:

• A mailbox can never warm itself.
• Two addresses on the same registrable domain cannot exchange warmup mail, even if they use different subdomains or belong to different Norbelys organizations.
• Mailboxes in the same organization can be peers when their registrable domains differ.
• Unhealthy, disabled, deleted, incompatible, or capacity-constrained mailboxes are not selected for new work.
• Internationalized domains, subdomains, and private suffixes are normalized before matching. A cosmetic spelling difference cannot bypass the domain rule.

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Relationship memory and rotation

The planner remembers directed sends, domain-to-domain exposure, active conversations, recent rotations, and cooldowns. It does not repeatedly roll the same random pair.

• A new cohort stays stable for its first three days.
• Beginning on day four, no more than 25% of a cohort rotates in one day.
• A member can rotate after seven days when a healthy replacement is available.
• A pair that separates waits 14 days before it can be matched again.
• A conversation lasts at most three days or three turns.
• A pair gets at most one new opener per day and no more than three consecutive conversation days.

When a cohort needs a peer, Smart Planner weighs the available candidates: Auto-adjust turns Smart Planner on. If you turn it off, Norbelys respects your manual volume target but still enforces domain separation, health, capacity, and idempotency protections.

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What happens before a message sends

A planned message is only an offer. The sender’s capacity coordinator makes the final decision immediately before transport. The send path is:

1. The cohort schedules a due slot between two current members.
2. The sender checks its mailbox-wide daily limit and minimum spacing.
3. Due campaign work reserves capacity first. Warmup may use only the remainder.
4. Norbelys atomically claims the offer and revalidates both participants, their domains, membership versions, and health.
5. The existing send pipeline opens the provider connection and transmits the message.
6. Delivery, placement, and reply results update the cohort’s operational state.

Duplicate queue deliveries, late results, and stale cohort jobs do not create a second send. If the coordinator or operational store is unavailable, warmup fails closed while normal campaign processing remains available.

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The volume ramp

The default configuration begins with a base target of five warmup messages and adds two per ramp day, up to a base ceiling of 40. The actual daily volume can be lower because Norbelys also applies weekday shaping, humanized variation, lighter days, cohort size, provider health, conversation limits, and remaining mailbox capacity. These are planning inputs, not guaranteed sends. For example, a cohort of five mailboxes offers only four possible peers to one sender, and a due campaign can consume the mailbox’s remaining capacity first.

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Configure conversations and schedule

The Warmup tab exposes only settings you can intentionally control:

• Language — English or Spanish for generated conversation copy.
• Reply rate — the desired share of eligible conversations that continue.
• Topics — up to eight themes that guide generated messages.
• Custom templates — up to five subject-and-body starting points. Spintax is supported; links are rejected.
• Sending window and time zone — when warmup activity may be offered.
• Daily start, growth, and ceiling — the requested ramp shape.
• Weekdays only — prevents new warmup activity on weekends.
• Auto-adjust — lets Smart Planner shape the plan from live signals.

Warmup messages do not copy a campaign’s Reply-To address. Replies return to the warmup sender’s own From mailbox, keeping campaign routing rules out of the warmup network. Warmup attribution is carried by internal message identity and address matching, not a visible warmup label in the subject or body.

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Read the runtime status

Settings describe your intent. Runtime status describes what the engine is doing now. The dashboard keeps them separate so an observed value is not mistaken for a saved preference. Runtime status includes:

• current ramp day and phase;
• cohort membership and next rotation;
• planned, sent, received, replied, and rescued counts;
• recent inbox and spam observations;
• provider-level placement where enough observations exist;
• health, deferral, and capacity reasons;
• the next eligible warmup activity.

A requested target above the sent count is not necessarily an error. Check the runtime reason first: campaign reservation, peer availability, a sending window, health backoff, or a small cohort may have reduced the safe volume.

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Decide when a mailbox is ready

Do not use a calendar day or a single placement percentage as an automatic launch button. Two weeks is a useful minimum observation period for a new low-volume mailbox, but higher-volume sender guidance can require a materially longer ramp. Before starting meaningful campaign volume, confirm all of the following:

• SPF, DKIM, and DMARC pass and align for the sending domain.
• The mailbox has at least two weeks of stable, gradual activity; use longer for a new domain or a much larger target volume.
• Recent placement has enough observations to be meaningful and is not trending downward.
• Authentication failures, hard bounces, deferrals, and spam observations are not increasing.
• The prospect list is verified and the campaign has a clear opt-out path.
• The campaign’s daily limit still leaves safe capacity for both real mail and ongoing warmup maintenance.

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Disable, remove, or restore a sender

Turning warmup off stops new matching and cancels future activity to and from that sender. Archiving or deleting it also invalidates pending work. Messages that were already transmitted are left unchanged. If the removal leaves at least four valid members, the cohort continues and fills the vacancy. Smaller cohorts are merged or dissolved. Restoring a sender creates a new membership; it does not revive its old slots or conversations. This behavior matters when a mailbox is disconnected while messages are queued: final validation makes those obsolete jobs no-ops instead of sending with stale state.

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Troubleshooting

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Why Norbelys warmup is different

Many tools can raise a counter and exchange opens or replies. Norbelys treats warmup as part of the same sending system that owns campaigns and sender health:

• Domain-safe by construction — every cohort uses distinct registrable domains, across subdomains and organizations.
• Memory instead of repeated randomness — pair exposure, conversations, rotation, and cooldown affect the next decision.
• One real capacity limit — campaigns reserve first; warmup never pretends a mailbox has a separate provider allowance.
• Validation at the last responsible moment — disabled senders and stale jobs cannot slip through after planning.
• No campaign routing leak — warmup does not reuse campaign Reply-To values.
• One operational picture — warmup, sender health, DMARC, and outbound sending live in the same product without claiming that warmup alone guarantees inbox placement.

For the underlying deliverability requirements, read Google’s email sender guidelines, Yahoo’s sender best practices, and Microsoft’s high-volume sender requirements.