Inbound vs outbound messages, explained
Every message your business sends falls into one of two groups: an answer to someone who wrote to you, or a message to someone who did not. The words may look the same, but messaging platforms treat the two very differently, and so does Spaces. Understanding the difference is the single most useful thing you can know about keeping a business account healthy while an AI agent helps you.
In one sentence
An inbound message is one a customer sends to you, and a reply to it continues a customer-started conversation; an outbound message is one you send first, to someone who has not written to you in that chat. Platforms watch outbound messages far more closely, so replies to people who wrote in have much more room than first messages.
In more detail
Think of a shop. A customer walking in and asking a question is inbound. You answering them is a reply. You standing on the pavement handing leaflets to passers-by is outbound. Both are legitimate, but nobody complains about the first, and plenty of people complain about the second when it is overdone.
Messaging platforms see it the same way. When someone writes to you, they have chosen to contact you, so your reply is expected. When you write first, the other person did not ask, and they may ignore it, block you or report it. Lots of unanswered or reported first messages are one of the clearest signals a platform has that an account is being used for spam.
A customer-started conversation is simply a chat where the customer wrote first. Once they have written, your answers and the back-and-forth that follows are replies. This is where most small businesses do most of their messaging: enquiries, booking questions, "are you open?", "how much?", order questions and follow-ups the customer asked for.
The line between the two is not always obvious. A follow-up you send three weeks after the customer last wrote is closer to outbound than inbound, even though it is in the same chat. A message to a past customer you have not spoken to in a year is outbound. A reminder about an appointment someone booked is outbound, but expected, which makes it far safer than a cold message.
Different platforms add their own rules on top. WhatsApp's Business Platform has a 24-hour window for free-form replies. Instagram has message requests for people you do not follow. LinkedIn limits how many people you can invite to connect. They all share the same idea: replies are easy, first messages are rationed. Here is the same business sending both kinds. Names and details are examples.
An example
| Who | Message |
|---|---|
| Customer (Leah, writes first on WhatsApp) | Hi, do you have any driving lessons free on Thursday evening? |
| AI agent (reply, inbound conversation) | Hi Leah, yes, Thursday at 18:00 is free. Lessons are £38 for an hour. Shall I pencil you in? |
| Customer | Yes please! |
| AI agent (reply) | Done. I will send a reminder the day before. |
| AI agent (next day, outbound but expected) | Hi Leah, a reminder that your lesson is tomorrow at 18:00. Reply here if you need to move it. |
| Owner's bad idea (outbound, unasked) | Messaging 200 old numbers from a 2023 spreadsheet about a spring offer |
Inbound and outbound side by side
| Inbound and replies | Outbound (first messages) | |
|---|---|---|
| Who wrote first | The customer | You |
| How platforms see it | Expected and welcome | Watched closely, especially when unanswered |
| Typical examples | Enquiries, booking questions, order questions | Cold outreach, re-engagement, introductions |
| Risk to the account | Low when replies are relevant and paced | Higher, and rises fast with volume |
| Room in Spaces | Not held back by daily limits | Tight hourly and daily new-chat limits |
| First days after connecting | Allowed from the first minute | Held back while the account warms up |
What counts as "wrote in"
For the generous reply room, Spaces needs to know the customer genuinely started or continued the conversation recently. A message counts as a reply to someone who wrote in when the person wrote in the last hour, or when the newest message in the chat is theirs and less than a week old. On email, a reply to an email from the last week counts the same way.
So if a customer asked a question on Monday and your agent answers on Tuesday, that is a reply. If the customer went quiet a month ago and you write to them again, that is treated much more like a first message, even though the chat already exists. The rule follows what a reasonable person would call a reply.
Outbound that is fine, and outbound that is not
| Message | Expected? | Sensible? |
|---|---|---|
| Reminder about an appointment the customer booked | Yes | Yes |
| Follow-up after a quote the customer asked for | Yes, within reason | Yes, once or twice |
| Thank-you message after a job, with a review request | Mostly | Yes, once |
| First message to someone who asked to be contacted on a form | Yes | Yes |
| Message to a past customer from two years ago | Not really | Only with care and in small numbers |
| The same offer to a bought or scraped list | No | No |
The safest outbound messages are ones the person would recognise and welcome. If they would ask "how did you get my number?", do not send it.
Common mistakes
- Treating a long-quiet chat as a reply. If the customer has not written for weeks, a new message is effectively outbound.
- Sending the same first message to many people. Platforms notice identical text, and Spaces refuses the same cold message sent to many people.
- Starting outbound on a newly connected account. Let it answer customers for its first weeks while the warm-up runs.
- Ignoring people who do not answer. A low answer rate on first messages is a warning, not a reason to send more.
- Carrying on after someone says stop. On WhatsApp, Spaces ends messages to anyone who says stop, unsubscribe or similar.
Why it matters for your business
- Most of your customer messaging is replies, and replies have the most room, so an AI agent can help without putting the account at risk.
- Knowing which messages are outbound tells you where to slow down and where to be careful.
- Keeping outbound small and expected protects the answer rate that platforms watch.
- It explains why Spaces lets replies through on day one while holding first messages back.
- It helps you set clear rules for your agent: answer freely, start chats only with people who expect you.
How Spaces handles it
Spaces counts replies and first messages separately on every account. A reply to someone who wrote in is never held back by the daily limit or the warm-up; only the gap between messages and a platform pushback can hold it. New chats have their own hourly and daily limits: on WhatsApp 5 an hour and 10 a day once warmed up, on Instagram 10 an hour and 100 a day, shared with likes, comments and follows, and on LinkedIn 100 new chats a day.
Replies to people who wrote in go out from the first day. New chats and similar outbound actions start lower and rise over four weeks of warm-up. On WhatsApp, new chats also wait up to 24 hours after connecting or reconnecting, a new chat only goes to someone who has messaged the number before or whom you marked as opted in, and when few people answer new chats, Spaces halves them and pauses them if hardly anyone answers. Replies still go out.
Many of the industries Spaces is set up for, such as restaurants, salons and shops, are described as customer-started conversations only, because that is where an AI agent does the most good with the least risk. Spaces lowers the risk; it cannot guarantee a platform will never restrict an account.
In short
Inbound is when the customer writes first, and your replies continue their conversation. Outbound is when you write first. Replies are where an AI agent shines and where accounts have the most room; first messages should be few, expected and written for the person receiving them.
FAQ
Is a reply always safe?
Replies are far lower risk than first messages, but they still need to be relevant, paced and honest. A flood of irrelevant replies, or replies that ignore what the customer asked, can still annoy people. Spaces keeps a gap between messages on every account for this reason.
If a customer messaged me last year, is a new message a reply?
Not really. For Spaces, a reply means the person wrote in the last hour or the chat's newest message is theirs and less than a week old. A message after a long silence is treated much more like a first message.
Are appointment reminders outbound?
Yes, technically, because you send them first. They are expected by the customer, which makes them much safer than cold messages. Because the customer has not just written, they count towards the daily message limits rather than the open room replies get.
Why does a new account start slowly?
New chats and other outreach start lower and rise over four weeks. On WhatsApp, new chats also wait up to 24 hours after connecting. Replies to people who wrote in go out from the first day. New accounts that start sending lots of first messages straight away are exactly what platforms look for.
Can my AI agent do outreach at all?
Yes, within the new-chat limits and with people who expect to hear from you. Spaces refuses bulk cold outreach, such as the same message to many people.
Does email work the same way?
Broadly, yes. Replying on a thread someone started is a reply, and writing to someone fresh starts a new thread, which has its own hourly and daily limits.
What is a customer-started conversation?
It is a chat where the customer sent the first message, such as an enquiry or booking question. Your answers and the back-and-forth that follows are replies, which is where most small businesses do most of their messaging.