1. Who this applies to
This policy applies to everyone who uses the send0 hosted service ("send0 Cloud"), including the AI agents and software acting on your behalf. You are responsible for everything sent or received through your account, whether a person or an agent did it. It forms part of our Terms of Service.
If you self-host the open-source edition, this policy doesn't govern your instance, but your email provider's own rules and the law still do.
2. What send0 is for
- Signing up for services and receiving verification codes, magic links and password resets
- Replying to people who wrote to your agent, and continuing those conversations
- Support, sales-operations, procurement, scheduling and collections conversations with people who expect to hear from you
- Transactional and operational mail that a recipient requested or reasonably expects
- Testing your own sign-up, password-reset and notification flows
3. What you may not do
Unsolicited and bulk mail
- Send cold outreach: mail to people who haven't contacted you, agreed to hear from you, or have no existing relationship with you
- Send newsletters, marketing campaigns, promotions or other bulk mail
- Use bought, rented, scraped or harvested address lists
- Rotate inboxes, domains or accounts to get around sending limits or suppression
- Keep mailing an address after it has bounced, complained or asked you to stop
Deception and fraud
- Phishing, or collecting credentials, payment details or personal data under false pretences
- Impersonating a person, company, government body or brand, including through display names or look-alike addresses
- Fraud, scams, advance-fee schemes or fake invoices
- Forging or hiding message headers or the true origin of a message
Harmful content
- Malware, ransomware or links to them
- Harassment, threats, stalking or hateful content targeting people
- Content that sexualises minors, or any illegal content
- Content that infringes someone else's intellectual property or privacy
Abusing the platform
- Creating accounts to evade a suspension, or creating large numbers of accounts automatically
- Using send0 inboxes to create fake accounts at scale on other services, or to break another service's terms
- Probing, scanning or attacking send0 or anyone else's systems, or interfering with other customers
- Reselling send0 or giving others access to your account without our written agreement
4. Sending limits and controls
To protect deliverability for everyone, these controls apply automatically:
| Control | How it works |
|---|---|
| Reply-only free tier | Free accounts can send only to addresses that have already emailed that inbox, plus the account owner's verified address. |
| Verified accounts | Every account must verify its email address. Disposable and temporary email addresses can't sign up. |
| Gradual limits | New accounts can send up to 50 messages a day. Limits rise as an account builds a clean sending record. |
| Automatic pause | Sending pauses if an account's complaint rate passes 0.3% or its hard-bounce rate passes 5%. |
| Suppression | Addresses that hard-bounce or complain are suppressed automatically and can't be mailed again from your account. |
| Custom domains for volume | Sending beyond the starter limits requires a verified custom domain with SPF, DKIM and DMARC. |
| Reserved addresses | postmaster, abuse, admin, support, noreply, security and billing can't be claimed as send0.email inboxes. Mail to postmaster and abuse at send0.email goes to the send0 team. |
Every message must identify its sender honestly. Ongoing conversational mail must stop when a recipient asks, and any message that isn't a direct reply must give the recipient an easy way to opt out.
5. Enforcement
We monitor bounce rates, complaint rates, blocklist reports and abuse reports. Depending on how serious a problem is, we may warn you, lower your limits, pause sending, suspend an inbox or close your account. For clear abuse such as phishing or malware we act immediately and without notice. We may also report illegal activity to the relevant authorities.
If we pause or suspend something, you'll receive an inbox.suspended event and an email explaining why. You can reply to that email to appeal, and a person will review it.
6. Reporting abuse
If you received unwanted mail from a send0 address, or think someone is misusing send0, email abuse@send0.email (or abuse@send0.dev; both reach the same people). Forward the message as an attachment, or include its full headers, so we can tell which inbox sent it. Mail sent to postmaster@send0.email reaches us too.
What happens next:
- A person reads every report, and we aim to respond within one business day.
- We find the inbox and account that sent the message and review their recent sending: who they mail, their bounce and complaint rates, and other reports.
- If the mail breaks this policy, we act as described in Enforcement: from a warning or lower limits to pausing sending, suspending the inbox or closing the account. Phishing, malware and other clear abuse are stopped at once.
- If you ask, we make sure that account can't email your address again.
- We reply to tell you what we did, though we may not share details about another customer's account.
Security vulnerabilities go to security@send0.dev.
7. Changes
We may update this policy as the service and the email ecosystem change. We'll post the new version here and, for significant changes, email account owners before they take effect.