Glossary
The words this documentation uses, defined once.
- Transactional email
- One email caused by one thing one person did: a receipt, a password reset, a verification code. As opposed to bulk email, which is one message sent to a list.
- DKIM
- A signature over the message, published as a DNS record, that lets the receiving server prove the mail came from your domain and was not altered. Three CNAME records here, one per key.
- SPF
- A DNS record listing who may send mail for your domain. A domain may have exactly one; adding a second breaks both.
- DMARC
- A DNS record telling receivers what to do when DKIM and SPF disagree, and where to send reports about it. Start at p=none and tighten once the reports are clean.
- MX record
- Where mail for a domain should be delivered. You only need one if you want to receive.
- Bounce
- The receiving server refused the message. Permanent means the address does not exist; transient means try later, which we do for you.
- Complaint
- A recipient pressed the spam button, reported back to us through a feedback loop. The address is suppressed.
- Suppression list
- Addresses on this workspace that hard bounced or complained. Sends to them are refused rather than attempted, which is what protects your sending reputation.
- Idempotency key
- Your own id for a send. A repeat within 24 hours returns the first result instead of sending again.
- Warm-up
- Raising volume on a new domain gradually, over days, rather than all at once. Receivers treat a domain with no history and sudden volume as a spammer, because usually it is one.
- Workspace
- The account boundary. Domains, keys, webhooks, suppression, and quotas all belong to one.
- llms.txt
- A plain-text file at the root of a site describing it for an AI assistant to read directly. Ours is the whole API in one fetch: https://emails.sh/llms.txt.