Sending limits
RadiusOS spreads your automatic follow-ups out over hours and days instead of firing them all at once. This is what keeps your email address in good standing, so the quotes and invoices you send by hand still land in the inbox.
Why the limits exist
Gmail, Outlook, and every other mail provider watch how you send. A hundred near-identical emails leaving your address in ten minutes looks like a machine, because it is one. The provider's response is to slow you down, and then to put your mail in the spam folder. That does not just affect your follow-ups. It affects the estimate you sent this morning and the invoice you send this afternoon, from the same address.
So RadiusOS sends slowly on purpose. A campaign that takes four days to go out and lands in the inbox beats one that goes out in an hour and lands in spam.
These limits are not RadiusOS being cautious with your time. They are the difference between your email working next month and not.
What you can set
Settings → Sending Limits, per workspace:
| Setting | Default | What it does |
|---|---|---|
| Your mailing address | Empty | Printed at the bottom of every follow-up. Required by law. Follow-ups will not send until you fill this in. |
| Most per day | 50 | The hard stop for automatic follow-ups in a day. |
| Most per hour | 15 | Stops a burst even when the daily number has room. |
| Gap between emails | 90 to 420 seconds | A random wait between sends. An exact rhythm is what a machine looks like. |
| When to send | 9:00am to 4:30pm | Your working hours, in your time zone. |
| Skip weekends | On | Weekend mail gets opened less and reported more. |
| Never email these | Empty | Domains to leave alone. Your own company, competitors, anyone who asked you to stop. |
Starting slow, then speeding up
The first time a workspace sends a follow-up, RadiusOS starts a warm-up. Day one allows 10 emails, and the daily allowance climbs by 5 each day until it reaches the number you set.
A brand-new sending address that suddenly emits two hundred messages is the single clearest spam signal there is. Building up over a couple of weeks is how you avoid it. You can raise your daily number whenever you want; the ramp still applies until it catches up.
Your mailing address, and why it blocks sending
US law (the CAN-SPAM Act) requires every marketing email to carry a working way to unsubscribe and the sender's real postal address. RadiusOS adds the unsubscribe link for you. It cannot invent your address.
So until you fill that field in, automatic follow-ups are held rather than sent. A PO box is fine. This applies to sequences and bulk sends, not to a one-to-one email you type and send yourself from a customer's record, which is ordinary correspondence.
Who gets skipped, and why
Before anything sends, RadiusOS screens the list and tells you who it left out:
| Reason | What it means |
|---|---|
| Asked not to be emailed | They used the unsubscribe link, or you marked them by hand. They will never be included again. |
| Their email came back undelivered | Mail to that address bounced. Their record says why, and sending resumes once you fix the address. |
| No email address on file | Nothing to send to. |
| Not a working address | The address cannot receive mail. Usually a typo. |
| Shared inbox, not a person | info@, sales@, support@ and similar. These reach a rota rather than a person, get few replies, and are a common source of spam complaints. You can include them for a specific send. |
| On your do-not-email list | The domain is in your blocked list. |
| Same address as another contact | Two records, one person. They get one email, not two. |
When someone unsubscribes
Every follow-up carries an unsubscribe link, and Gmail shows its own unsubscribe button next to your name. Either one marks that contact as opted out immediately.
Two things happen straight away. Anything already queued for that person is cancelled, so they do not keep receiving a campaign they just left. And the opt-out stays with that contact in that workspace only. If the same person is also a contact in a different RadiusOS workspace, they have said nothing to that business.
You can see and undo an opt-out on the contact's record. Undo it only when the person has actually asked you to start emailing them again.
Emailing people who never asked
If you bought a list, or scraped one, be careful. In the United States you may email a list you did not build as long as every message carries a working unsubscribe link and your postal address, both of which RadiusOS handles once your address is set.
Canada and most of Europe are different. Canadian anti-spam law and European data protection rules both require the person to have agreed beforehand. Emailing a purchased list into those countries is against the law, not merely frowned upon.
Bought lists also carry dead addresses that have been turned into traps. Mail one and your domain can be blocklisted, which affects every email your business sends. RadiusOS flags recipients whose address suggests Canada or Europe so you can leave them out, but a .com address can belong to someone in Berlin, so the flag is a prompt to think rather than a guarantee.
The safest list is one you built: past customers, people who asked for an estimate, anyone who gave you their address. Reply rates on those are many times higher anyway.