Account verification and sending limits

SpacePost shares sending infrastructure and reputation between customers, so we verify who is sending and limit how fast new accounts can grow. The checks are light for legitimate senders. This page lists all of them.

Email verification is required. You must confirm your email address before you can create API keys or send.
You accept the Acceptable Use Policy (AUP) when you sign up. It prohibits spam, phishing, malware, purchased lists and deceptive content.
Disposable email addresses are refused at sign-up.

Sending profile

Before you can add your first domain, your team completes a short sending profile:

Field	What we ask
Company	Legal or trading name
Website	Where we can see who you are
Use case	For example transactional, marketing, or both
Description	What you send and to whom
Expected volume	Emails per month, roughly
Opt-in method	For marketing mail: how your recipients agreed to hear from you

This is not a hurdle, it is how we tell a SaaS sending receipts from a bulk mailer. Be specific and honest: an accurate profile speeds up any later review.

Domain checks

When you add a domain:

Free mail and disposable domains cannot be added (gmail.com, outlook.com, yahoo.com and similar). Send from a domain you own.
Domains registered less than 7 days ago are refused. Brand-new domains are heavily used for abuse. Come back once the domain is a week old.
The usual DNS verification applies.

Trust levels

Every team has a trust level that sets its daily sending cap. It sits on top of your plan’s monthly quota.

Level	How you get it	Daily cap
New	Every new team	100 emails per day for the first 7 days (the sandbox)
Verified	Automatic after 7 days when you have a verified domain, low bounce and complaint rates and no open abuse flags. Immediate when you are on a paid plan.	max(1,000, 2x your best day of the last 14 days), up to 50,000 per day
Trusted	Manual review by the SpacePost team	Plan limits only, no daily cap

The verified cap grows with you: send 3,000 emails on your best day and tomorrow’s cap is 6,000. If you need to go faster, for example for a planned launch, contact support@spacepost.dev and ask for a review for Trusted.

When you hit your daily cap the API returns 429 daily_quota_exceeded; the monthly plan quota returns 429 monthly_quota_exceeded. See Errors.

Content filtering

Every email is checked before it is sent:

Executable attachments are blocked (for example .exe, .scr, .bat, .js and other file types that run code).
Phishing and spam indicators are scored (deceptive links, credential harvesting wording, known bad patterns). Content over the threshold is blocked.

A blocked send returns HTTP 451 with the error name security_error:

{
  "statusCode": 451,
  "name": "security_error",
  "message": "The email was blocked by content filtering."
}

Do not retry a security_error without changing the content. If you believe a legitimate email was blocked, contact support with the request details.

Automatic pausing

Teams with unhealthy bounce or complaint rates are paused automatically:

bounce rate above 5% (with at least 10 bounces), or
complaint rate above 0.2% (with at least 3 complaints),

measured over your last 1,000 emails. While paused, sends return 403 sending_paused. See Automatic pausing for recovery.

Recipient domains that cannot receive mail

Before sending, SpacePost checks that each recipient’s domain can receive email. Recipients whose domain does not accept mail (no mail server) are skipped, and an email.suppressed event is recorded. This keeps typos like user@gmial.con from inflating your bounce rate. Other recipients on the same email are still delivered.