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A new WhatsApp number that sends hundreds of messages on its first day is the pattern WhatsApp restricts fastest. The warm-up plan gives every number in a project a daily allowance that starts small, grows over the number’s first weeks, and shrinks when the number’s health falls. The warm-up plan is a BanSafe Lite feature, included on Standard and Pro. It is off until you turn it on, and turning it off is always allowed.

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The allowance

Each number gets one allowance per day. It depends on two things: how long the number has been active, and its current health band.
  • On its first day a number may send 20 messages.
  • The allowance grows in a straight line to the per-number daily cap of 2,000 over 14 days.
  • The number’s health band scales the result: good keeps all of it, fair three quarters, poor a half, failing a quarter. A number that has not been measured long enough to have a band keeps all of it, because the ramp is already the cautious part.
  • The allowance never falls below the first-day figure and never rises above the cap.
A number seven days in, in good health, may send 1,010 messages that day. The same number in poor health may send 505. You can change the first-day figure and the length of the ramp. The 2,000 per-number daily cap is fixed, and campaigns already obey it.

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The day

The allowance resets at midnight in the number’s own country, worked out from its phone number. A Brazilian number rolls over at midnight in Brazil, a British number at midnight in Britain. The read below reports the exact instant of the next reset.

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How long a number has been active

The ramp counts from the earliest moment Polymorfa can prove the number was active: when it was linked, or the oldest message in its history if that is earlier. A number whose age cannot be proven starts the ramp on the day the plan is turned on, and Console says so. The current number Health response exposes that evidence as tenureSource: history means an older history record anchors the ramp, link means a recorded pairing does, and plan means neither was available so the project opt-in is the anchor. Legacy evidence that cannot be classified reports null rather than guessing a source.

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What happens at the allowance

Immediately before transport, Polymorfa durably reserves one slot in the number’s active allowance day. Concurrent sends and runner restarts use the same counter, so they cannot spend the final slot more than once. A granted reservation remains counted even if transport later fails or its result cannot be confirmed. This keeps the configured allowance a strict ceiling. A send past the day’s allowance is refused before transport. Nothing on the number changes and no restriction is applied; retry the unsent message after the next reset. Replaying the same attempt within the same policy window returns the same refusal. If Polymorfa cannot durably authorize a slot, it pauses the send before transport and returns 503 bansafe_accounting_unavailable with retryAfter: 5. Retry the same message after that interval without creating parallel retries. If another attempt already received a slot for the same logical send, Polymorfa returns 409 bansafe_send_outcome_unknown. It does not send the message again. Do not retry it automatically; reconcile its delivery state before deciding whether to create a new message. Creating a group and adding people to a group do not count against the allowance. Safety limits still apply to both. Messages sent by simulated test-mode sessions do not consume a daily allowance. The allowance is a ceiling among ceilings. Your plan’s throughput, a campaign’s own pacing, and any safety limit in force all still apply, and the smallest one wins.

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Turn it on

The warm-up plan is in Console and on both APIs, with the same settings and the same responses: Reading needs sessions:read; changing needs sessions:manage. On the Platform API, a signed-in team member must be an organization owner, admin, or developer to change the plan; reading needs organization membership.
The body is a partial update: send only the settings you want to change.
The response carries the plan, the cap the ramp climbs to, and the allowance day by day for a number in good health, so you can show the curve without recreating it:
entitled is true when at least one number in the project is on a plan that includes BanSafe Lite. When it is false, turning the warm-up plan on is refused with warmup_plan_not_entitled, and entitlementReason carries the sentence that refusal returns. A write is stored before any number is told about it. If a connected number does not confirm the new plan, the request answers 503 propagation_pending and the plan is already stored; retry the request and it is pushed again.

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See one number’s allowance

GET /platform/bansafe/health/{session} carries a warmup block for the number:
enabled is false with a null allowance when the project has no warm-up plan: there is no ceiling, rather than a ceiling of nothing. curve is drawn at the number’s fresh current Health band. Without a fresh supported estimate, the band is unknown and the cautious tenure ramp applies without an additional Health reduction. sentToday comes from the durable active allowance window. A successful read returns 0 before the first reservation of the day. Health history does not contain allowance fields.