WhatsApp’s 24-Hour Window — how to win inside the rules
See concrete product examples & templates: Resource Hub: WhatsApp Growth Node
TL;DR (link each claim to a primary source)
- 24-hour customer service window: reply freely for 24h after the user’s last message; outside 24h you must use approved templates. whatsapp.com/legal/business-policy
- Opt-in is required to initiate messaging; you must honor opt-out and provide clear controls. whatsapp.com/legal/business-policy
- Conversation billing is per 24-hour category window; Business Help Center defines categories and billing. facebook.com/business/help/2225184664363779
- Free entry points: Click-to-WhatsApp Ads or Page buttons can open a 72-hour free window if you respond within 24h. facebook.com/business/help/2225184664363779
- Template categories: Marketing, Utility, Authentication; quality ratings affect delivery. facebook.com/business/help/722393685250070 · facebook.com/business/help/766346674749731
Problem (who/what/where)
Most “WhatsApp automation” breaks on the only rules that matter.
Teams spam outside the 24-hour care window, misuse template categories, or message without explicit opt-in.
The result: blocked numbers, rejected templates, rising costs, falling CSAT.
Winning here is not about clever copy.
It is operational discipline: session hygiene, consent proof, correct templates, and predictable costs.
Definitions (short & source-linked)
- 24-hour customer service window. After a user messages you, you may send free-form replies for 24 hours. Outside 24h, only template messages are permitted. policy
- Template categories. Marketing, Utility, Authentication; each opens a billed conversation window and is subject to quality ratings. samples · quality
- Opt-in. Explicit permission to receive messages; required before initiating business-initiated conversations. policy
- Free entry point. Ads that click to WhatsApp or Page action buttons may open a 72-hour free window if you reply within 24h. billing
Evidence & pattern (the “why this works”)
1) Treat the 24-hour session as your core lever
Most failures are time failures. Teams reply late, then force a promotion through a Utility template and get rejected—or deliver but pay more for less trust. The fix is a session-first design:
- Detect user pings instantly.
- Route to the right responder (agent or agentic flow).
- Close within 24 hours with clarity, not with a stall.
When the window is open, conversational tone wins. Outside it, your copy must fit a pre-approved template. Build your playbooks around that constraint, not against it.
Implication: instrument SLA and prioritization around session expiry, not just ticket backlog. The fastest team owns the cheapest and most compliant conversation.
2) Categorize templates conservatively, then optimize
Template categories are not labels—they are billing and policy gates. “Order shipped” is Utility; “We miss you—20% off” is Marketing; one-time passcodes are Authentication. Mislabeling gets you rejections or quality downgrades that throttle delivery later.
Design templates like API contracts:
- One intent, one purpose, one clear user expectation.
- Variables named and validated (no bait-and-switch).
- Buttons map to real actions (confirm, track, reschedule).
Quality ratings update on rolling feedback. If users block or report, your template health drops, then delivery follows.
Implication: your copy review is a policy review; ops owns it as much as marketing does.
3) Consent is not a footer—make it a ledger
Meta requires opt-in to initiate messages and clear opt-out paths. “Implied consent” via an order does not give you a blank check for promotions. Store who consented, when, and for what. Surface it to agents so they never guess.
GDPR and regional privacy rules raise the bar further. Whether you sell in the EU or not, a consent ledger reduces disputes and protects template quality.
Implication: consent artifacts must be queryable and exportable. If you cannot prove it, you do not have it.
4) Exploit free entry points to bend cost curves
Click-to-WhatsApp Ads or Page buttons can open a 72-hour free window if you respond within 24h. Use this for onboarding, post-purchase guidance, or churn saves. Time your sequences to fit the 72-hour arc: assist → verify → upsell—all at zero template cost.
Implication: creative + routing + reply-within-24h = free 72h runway. Treat it as an acquisition primitive, not an afterthought.
Microfacts (numbers your team can quote)
| number | unit | year | source |
|---|---|---|---|
| 24 | hours of free-form replies after a user message | 2025 | policy |
| 72 | hours of free messages from free entry points (reply within 24h) | 2025 | billing |
| 3 | template categories (Marketing, Utility, Authentication) | 2025 | templates |
| 1 | explicit opt-in required to initiate | 2025 | policy |
| 1 | quality rating per template monitored in a rolling 24h window | 2025 | quality |
Implementation checklist (copy/paste to JIRA)
- Session SLA. Prioritize WhatsApp threads by time-to-expiry; alert at T-90/T-30/T-10 minutes.
- Routing. User intent → human agent for edge cases; agentic flow for structured paths; guaranteed human escalation options (phone, email, web form).
- Templates. Maintain a catalog mapped to Marketing/Utility/Authentication; pre-approve localized versions; lint variables and buttons; archive low-performers.
- Consent ledger. Track source, timestamp, scope (by category); store opt-out events; expose to agents; export on request.
- Free entry orchestration. For Click-to-WhatsApp Ads and Page CTAs, enforce “reply within 24h” to unlock 72h free; schedule sequenced touches inside that window.
- Quality guardrails. Monitor template quality rating; auto-pause when trending down; add friction (confirmations) before sending a risky template.
- Copy standards. No disguised promos in Utility; Authentication templates contain only OTP and context; ban spammy phrasing and irrelevant capitalizations.
- Observability. Dashboards for conversation mix, cost per cohort, session expiry misses, template rejection reasons; daily drill-downs.
- Policy updates. Watch Business Policy and Help Center changes; re-review playbooks quarterly; re-approve templates that drift.
- Data hygiene. Deduplicate numbers; respect regional quiet hours; rate-limit retries; fail closed on policy ambiguity.
FAQ (expanded answers)
Q1. Can I send promos inside the 24-hour window without a template?
Yes—if you are replying within 24h of the user’s last message. The moment you fall outside 24h, you must use an approved Marketing template to initiate. policy
Q2. Are WhatsApp templates hard to get approved?
Not if you respect category intent and clarity. Keep one purpose per template, no bait, and ensure variables do not change meaning. If quality drops (blocks, reports), delivery suffers. templates · quality
Q3. What is the cheapest way to start user conversations?
Free entry points. Ads that click to WhatsApp or Page action buttons can open a 72-hour free messaging window if you reply within 24 hours. Use that runway for onboarding, guidance, and a single, well-timed nudge. billing
Q4. Do I need a human in the loop?
Yes. Meta requires clear escalation paths during the 24h window. Automation is fine; easy handoff is required. policy
Further reading (primary only)
- WhatsApp Business Policy — 24-hour replies, opt-in, templates, and escalation.
- Conversation-based pricing (Business Help Center) — categories, billing, free entry windows.
- Sample templates (Business Help Center) — structure and examples.
- Template quality rating — how quality states impact delivery.
- Click-to-Message ads (Meta) — how to start WhatsApp threads from ads.