The seven-day reply window on Messenger, and why WhatsApp has nothing like it
Last updated 24 October 2026
Last updated 24 October 2026.
Every Meta messaging channel closes a free-form reply 24 hours after the customer's last message. That part is the same everywhere and well known.
What differs is what reopens it, and the difference is larger than most people building on these platforms realise. On WhatsApp, reopening the window needs an approved message template, and until you have one the honest answer to your customer is that they have to write again. On Messenger and Instagram, a person gets seven days.
That is not a loophole. It is a tag Meta created deliberately, for exactly the case where the window is most painful.
What the tag is
HUMAN_AGENT is a message tag on the Messenger Platform. Sending with it extends the reply window from 24 hours to seven days, and it carries one condition: the message must come from a human.
Meta's own framing is that it exists so a person can answer something an automated reply could not. A customer asks something the bot cannot handle at five on a Thursday; the person who can answer is not back until Sunday; without the tag that customer is unreachable by the time anyone reads the question.
Why this matters more than it sounds
If your product hands conversations to a person when it is unsure — and any honest assistant does — then the handover promise is only as good as your ability to deliver the answer.
On WhatsApp, a handover has to be resolved inside a day. Past that, the most useful thing the software can tell the business owner is that their customer is now unreachable, which is a bad sentence to have to write and a worse one to read.
On Messenger and Instagram the same handover has a week. The customer who asked something awkward on Friday still gets a real answer on Monday. The feature that was a liability on one channel is a strength on another, with no change in the product.
This is the single clearest way in which the newer channels are better than the one everybody builds for first, and almost nobody says so.
How it is misused
The tag is for a human. Sending an automated reply under it is the misuse Meta's policy names explicitly, and it is not a grey area.
It is also easy to do by accident. A system that routes everything through one send function, and reaches for the tag whenever a message would otherwise be rejected, will tag bot replies without anyone deciding to. The right shape is for the tag to be unreachable from the automated path at all — a separate method that only the code handling a human's typed reply can call.
In our own implementation the agent has no way to send tagged. The inbox composer and the owner's relay from their phone do, because those are the two places where a person is demonstrably writing.
The four rules worth knowing
Check before you send, not after. Past seven days Meta rejects the message. Repeated rejected sends are the kind of signal that costs a Page its messaging permission, so the age of the customer's last message is worth knowing before you call the API rather than discovering from the error.
Inside 24 hours, do not tag. A plain RESPONSE is correct and is a truer record of what happened. Tagging inside the window is not an error, but it muddies your own logs.
The tag does not apply to WhatsApp. There is no equivalent. Template messages are the only route, they need approval, and they are charged for.
It does not make the conversation free. It makes it possible. On Messenger and Instagram there is no Meta per-message fee at all, so the question of cost does not arise; on WhatsApp, where it would, the tag does not exist.
What it looks like in practice
Three states, and software that answers customers needs all three:
| Messenger and Instagram | ||
|---|---|---|
| Automated reply allowed | 24 hours | 24 hours |
| A person may reply | 24 hours | 7 days |
| Reopened by | an approved template | the human agent tag |
| Meta's per-message fee | yes | none |
The first row is the agent's question. The second is the inbox composer's. A system with one window constant cannot tell them apart, and will either refuse replies it was allowed to send or send ones it was not.
Questions
How long do I have to reply to a Facebook Messenger message? An automated reply is allowed within 24 hours of the customer's last message. A person may reply for up to seven days, using Meta's human agent tag.
What is the HUMAN_AGENT tag? A message tag on Meta's Messenger Platform that extends the reply window to seven days, on the condition that the reply comes from a human rather than from automation.
Can I use the human agent tag for an automated message? No. Meta's policy for the tag requires a human to be writing the reply, and using it to carry automated messages risks the Page's messaging access.
Does WhatsApp have a seven-day window? No. On WhatsApp the only way to message a customer after 24 hours is an approved message template, which Meta reviews and charges for.
Does Meta charge for Messenger messages? No. The Messenger Platform is free to use. WhatsApp is the channel where Meta charges businesses for service messages, since 1 October 2026.