Email deliverability basics for small businesses
Deliverability is whether your emails reach the inbox rather than spam. For a small business it comes down to four things: a proper domain with SPF, DKIM and DMARC set up, a mailbox that sends a steady, modest amount, messages people expect and answer, and quick removal of anyone who does not want to hear from you. This guide explains each one in plain language, shows how to warm up a mailbox, and covers what changes when an AI agent replies to email for you through Spaces.
What deliverability means
When you send an email, the receiving provider, such as Gmail or Outlook, decides where it goes: the inbox, a tab such as Promotions, the spam folder, or nowhere at all. It decides based on who you are, how your mailbox behaves and how people react to what you send.
You cannot control that decision, but you can make it easy. Most deliverability problems for small businesses come from a missing setting on the domain, a sudden jump in sending, or emails people did not ask for.
Use your own domain
An address like hello@yourbusiness.co.uk looks more trustworthy than a free webmail address, and it lets you set up the records that prove your emails are really from you. Google Workspace and Microsoft 365 both let you use your own domain with Gmail or Outlook.
Guidance also gives business mailboxes more room. Here is what it recommends, written in our own words:
This is published provider guidance, written in our own words and last updated on 28 Aug 2026. It is advice, not a promise from the platform, and the platform can change what it watches for at any time.
- Gmail allows up to 500 emails a day, but the recommendation is 50 to 100 a day, or 100 to 150 on Google Workspace.
- Start a new mailbox at 20 to 50 emails a day and build up slowly.
- Outlook and other mailboxes should follow the same recommendations as Gmail.
- Spread emails out over the day instead of sending them in bursts.
SPF, DKIM and DMARC in plain language
These are three short records you add to your domain's settings, usually where you bought the domain. Your email provider gives you the exact values to paste in.
| Record | What it does | In everyday terms |
|---|---|---|
| SPF | Lists the servers allowed to send email for your domain. | A guest list: only these senders may use our name. |
| DKIM | Adds a digital signature to each email. | A wax seal that shows the letter was not changed on the way. |
| DMARC | Tells providers what to do if SPF or DKIM fail, and can send you reports. | Instructions for the doorman when someone is not on the list. |
Gmail and Yahoo tightened their rules for senders in 2024, and authentication is now expected of anyone who sends regularly. Even if you only send a few emails a day, setting all three up is one of the most useful things you can do.
Setting them up step by step
- Find out where your domain's DNS is managed. It is usually the company you bought the domain from, or your website host.
- In Google Workspace or Microsoft 365, open the admin settings for your domain and find the email authentication section.
- Copy the SPF record your provider gives you and add it to your DNS. If you already have one, add to it rather than creating a second.
- Turn on DKIM in your email provider's admin settings and add the record it shows you.
- Add a DMARC record. Many businesses start with a setting that only reports, then tighten it once they are sure everything sends correctly.
- Wait for the changes to take effect, then send a test email to a Gmail address and check the message details show it passed.
- If you use another service that sends as your domain, such as a booking tool or newsletter service, follow its instructions to add it too.
Warm up a new mailbox
A brand-new mailbox, or one that has been quiet for months, has no reputation yet. Guidance says to start at 20 to 50 emails a day and build up slowly. When you connect a mailbox to Spaces, new email threads follow a warm-up whatever your agent asks for:
| Since connecting | New threads an hour | New threads a day |
|---|---|---|
| Week 1 | 5 | 20 |
| Weeks 2 to 4 | 6 | 30 |
| After that | 8 | 40 |
A new chat here is a new email thread. Replies on a thread someone started are not held back by the warm-up. Spaces sends one email at a time to one person, never bulk email.
The limits Spaces enforces
| Action | Spaces limit per account |
|---|---|
| Emails | Up to 80 a day, at least 30 seconds apart |
| New email threads | 8 an hour, 40 a day |
Each email goes to one person, with at most 4 people in cc, no bcc and no tracking. Spaces is for conversations, such as answering enquiries and following up with people who asked, and it is not a tool for campaigns or newsletters.
Write emails people want
Providers watch how people react. Replies help. Being marked as spam hurts a great deal. The best thing for deliverability is an email the person expected and wants to answer. Here is a before and after. Names and details are examples.
| Instead of this | Try this |
|---|---|
| Subject: AMAZING OFFER inside!!! Book now and save | Subject: Your boiler service quote |
| Dear customer, please find our full price list attached and click here to book. | Hi Mark, thanks for asking about a boiler service. For your combi it would be the price on our list, including the safety certificate. Would a morning next Tuesday or Wednesday suit? |
- Use the person's name and answer what they asked.
- Keep subject lines plain and specific. Capitals and exclamation marks look like spam.
- Keep links few, and use your own domain rather than link shorteners.
- Make it easy to reply. A question at the end invites one.
- Use the same sender name and address every time, so people recognise you.
Look after your contacts
- Only email people who gave you their address and expect to hear from you. Bought lists are the fastest route to the spam folder.
- Remove addresses that bounce. Repeated bounces tell providers the list is not well kept.
- Stop straight away when someone asks. Any message to someone who said stop, unsubscribe or similar in that chat.
- Do not send the same cold email to many people. The same cold message sent to many people. Spaces refuses copy-paste blasts.
What if your emails are landing in spam?
| Check | What to do |
|---|---|
| SPF, DKIM and DMARC | Send a test to a Gmail address and look at the message details. Fix anything that fails. |
| Sending volume | Has it jumped recently? Drop back and build up slowly. |
| Content | Remove link shorteners, heavy images and salesy subject lines. |
| Who you email | Stop emailing people who never reply or did not ask to hear from you. |
| Other senders on the domain | A newsletter tool sending as your domain can affect the whole domain's reputation. |
| Your provider's messages | If Google or Microsoft has warned or limited the mailbox, follow its steps. |
What happens at a limit in Spaces
The account reached its hourly limit, or a message came too soon after the last one. Nothing. Your agent waits the time Spaces gives it and tries again with the same message. The account reached its daily limit. Sending starts again the next day.
If Google or Microsoft signs the mailbox out or asks for a check, sending pauses and the mailbox shows as needing attention in your dashboard. Reconnect it from there once you have dealt with it.
Notes to give your AI agent
Email rules for our mailbox:
- Reply to every enquiry within working hours. Answer what they asked, by name.
- Plain subject lines, no capitals or exclamation marks.
- One link at most, on our own website. No attachments unless asked.
- Only start a new email thread with people who asked us to contact them.
- Never send the same email to more than one person.
- If anyone asks us to stop, apologise once and do not email them again.
- If Spaces says to wait, wait. If the mailbox needs reconnecting, tell me.Who you message
Summing up
Good deliverability is mostly good habits. Use your own domain with SPF, DKIM and DMARC, warm up new mailboxes, send a steady, modest amount, and write emails people expected and want to answer. Spaces keeps every mailbox inside careful limits and sends one email at a time to one person, which suits the conversations most small businesses actually have by email.
Pricing
FAQ
Why are my business emails going to spam?
The usual causes are missing SPF, DKIM or DMARC records, a sudden jump in sending, salesy content, or emails to people who did not expect them. Work through the checks in this guide one at a time.
Do I really need SPF, DKIM and DMARC for a small business?
Yes. They prove your emails are really from you, and Gmail and Yahoo now expect authentication from regular senders. Your email provider gives you the exact records to add.
How many emails can I send a day?
Guidance says Gmail allows up to 500 a day but recommends 50 to 100, or 100 to 150 on Google Workspace. Spaces allows up to 80 emails a day per mailbox, at least 30 seconds apart.
Can I use Spaces to send a newsletter?
No. Spaces sends one email at a time to one person, with no bcc and no tracking. Use a dedicated newsletter service for campaigns, and set it up to send as your domain correctly.
Does a new mailbox need to warm up?
Yes. Guidance says to start a new mailbox at 20 to 50 emails a day and build up slowly. Spaces applies a warm-up to new email threads automatically, while replies on threads someone started are not held back.
Is a free webmail address fine for business?
It works, but your own domain looks more trustworthy and lets you set up authentication. Google Workspace and Microsoft 365 both let you use your own domain with Gmail or Outlook.
What should I do if someone marks my email as spam?
Stop emailing them and look at why. Spam reports hurt your reputation more than almost anything else, so keep to people who asked to hear from you.
Can my AI agent reply to emails without hurting deliverability?
Yes, if it writes like a person: replies to what was asked, plain subject lines, few links and no copy-paste emails. Spaces keeps the pace and volume inside careful limits.