Postfaro is built so that you can send a big campaign in one go — from your CRM, Outlook or newsletter plugin — without worrying about limits. This page explains what happens behind the scenes.
Items marked [CONFIRM] describe behaviour that will be fixed during final system testing.
The daily cap: 5,000 emails per account
- Your plan includes up to 5,000 emails per day.
- The cap is per account, shared by all your sender addresses. If
news@sends 3,000 andevents@sends 2,000, the day is full. - Each recipient counts as one email. A message to 3 recipients counts as 3.
- A day runs from 00:00 to 24:00 UTC [CONFIRM].
- Use it or lose it: unused capacity does not carry over. If you send nothing on Monday, you still have 5,000 on Tuesday — not 10,000.
- Addresses on your cancelled addresses list are dropped before sending and do not use up your cap [CONFIRM].
What happens when you send more than that
Nothing breaks. Postfaro accepts every message your tool sends and puts the ones that don’t fit today into a queue. Each day, the next 5,000 are sent, until the queue is empty.
Example — 22,000 emails sent on a Monday morning (after warm-up):
| Day | Sent | Still queued |
|---|---|---|
| Monday | 5,000 | 17,000 |
| Tuesday | 5,000 | 12,000 |
| Wednesday | 5,000 | 7,000 |
| Thursday | 5,000 | 2,000 |
| Friday | 2,000 | 0 |
As soon as the messages are queued, we email you a summary: “22,000 emails queued — last send expected on Friday, 20 March.” The queue sends every day, including weekends [CONFIRM].
Your tool sees success immediately. From your CRM’s point of view, every message was accepted. The waiting happens at Postfaro. That also means you can switch your tool back to its normal mail server right after it has handed over the campaign (see the Vtiger guide).
Order: messages are sent in the order we received them, across all your sender addresses [CONFIRM]. If you start a second campaign while the first is still queued, the second one waits for the first.
Following and cancelling the queue
In the customer panel, Queue shows each batch: how many were accepted, sent, waiting and dropped, and the expected last send date.
You can cancel a batch (or everything still waiting) at any time — for example if you spot a mistake in the campaign. Cancelled messages are deleted and are not sent. Messages already delivered cannot be recalled.
Queued messages expire if they cannot be delivered within [30] days [CONFIRM].
Warm-up: why your first weeks have a lower limit
Mailbox providers such as Gmail and Microsoft distrust a brand-new sender that suddenly sends thousands of emails. Reputation is built gradually. That’s why each new sending domain goes through warm-up: the daily limit starts low and rises step by step to 5,000.
Indicative schedule [PLACEHOLDER — final numbers are set by the warm-up system and shown in your panel]:
| Period | New domain (Path A, or a new domain in Path B) | Established domain or subdomain (Path B/C with a sending history) |
|---|---|---|
| Days 1–2 | 200 / day | 500 / day |
| Days 3–4 | 400 / day | 1,000 / day |
| Days 5–7 | 750 / day | 2,000 / day |
| Week 2 | 1,000 → 2,000 / day | 3,000 → 5,000 / day |
| Week 3 | 3,000 / day | 5,000 / day |
| Week 4 | 4,000 → 5,000 / day | 5,000 / day |
- Warm-up typically takes 3–4 weeks for a new domain and 1–2 weeks for an established one.
- The limit only goes up if your bounce and complaint rates are low. If they rise, warm-up slows down.
- You can send any amount during warm-up — it simply queues for longer. The “Batch queued” email always shows the realistic last send date.
- Tip: during warm-up, send first to your most engaged contacts (recent customers, people who opened recently). Good early engagement speeds up warm-up.
Pacing within the day
Even within your daily limit, we don’t send everything in the same minute. We pace delivery per receiving provider (Gmail, Microsoft, Yahoo, others), the way those providers prefer. A message accepted at 09:00 may be delivered later in the day. This is normal and protects your reputation.
Your first day is a trial
The first day of real sending on a new account is watched closely. If something looks wrong — too many bounces or complaints — sending pauses automatically before a bad list damages your new domain’s reputation.
Automatic pause
Sending pauses automatically, at any time, if:
- more than 2% of your messages hard-bounce (addresses that don’t exist), or
- more than 0.1% of recipients mark your email as spam, or
- our content checks find phishing, malware or similar content.
[CONFIRM measurement window and minimum volume.]
These limits are stricter than the mailbox providers’ own (Gmail, for example, expects spam complaint rates to stay below 0.3%). Stopping early protects your domain before providers start rejecting your mail.
While paused:
- queued messages wait — nothing is lost;
- new messages from your tool get a temporary “try again later” response (SMTP 451). Most tools retry for a while; if the pause lasts long, your tool may eventually report those messages as failed;
- you receive an email explaining the reason and what to do (usually: remove bad addresses, check where the list came from, then resume from the panel or ask support).
Cancelled addresses
Some addresses are never sent to again:
| Reason | What it means |
|---|---|
| Hard bounce | The address does not exist or permanently refuses mail |
| Complaint | The recipient marked your email as spam |
| Unsubscribed | The recipient used the one-click unsubscribe button |
| Shared block | The address is on Postfaro’s do-not-mail list for all customers (for example a known spam trap) |
Messages to these addresses are accepted from your tool but not delivered. You find them in the panel under Cancelled addresses, with the reason and date, and you can export them as CSV. We don’t change anything in your CRM or plugin, so we recommend removing or opting out these addresses in your own tool regularly.
Not for urgent email
Because of the queue, Postfaro is not the right path for email that must arrive within seconds: order confirmations, password resets, two-factor codes, or day-to-day correspondence. Keep those on your existing mail server. Our setup guides show how to route only campaign email to Postfaro.