| Universe | A separate world with its own mail, logins, people, clock and settings. Use one per environment or test suite. See Universes. |
| Organization | Your company’s account on simmail. It owns universes, members, API keys and a plan. See Organizations and roles. |
| Login (account) | An address and password your app uses for SMTP and IMAP. Logins are made under Settings → Mail logins in a universe. See SMTP and IMAP. |
| Mailbox | Where a message lands. simmail creates a mailbox for every address that receives mail, with folders such as INBOX, Sent and Junk. |
| Persona (person) | A simulated person behind an address. They read, reply, click, remember and promise. See People. |
| Temperament | How a persona behaves by default: responsive, busy, procedural, skeptical, flaky, difficult or ghost. |
| Stranger | A persona simmail makes on the spot when your app writes to an address nobody plays yet. |
| Operator | An address that sends mail into simmail: your app or you. Operators are never turned into personas. |
| Case | A shared situation, such as a deal or a support ticket. Your system pushes what it knows; the people on the case stay consistent with one story. See Cases. |
| Simulated clock | Each universe’s notion of now. It can run live, faster, frozen, or jump ahead. See The simulated clock. |
| Job | Something a persona will do later, such as a reply due in 40 minutes. Jobs run when the simulated clock reaches them. |
| World | Your universe’s company profile and the mail the world sends it on its own. See The World module. |
| Inbound stream | One kind of mail the world sends, such as leads or spam, at a set rate. |
| Health report | The spam score, link check, client compatibility and accessibility of one email your app sent. See The health report. |
| Junk | The folder a persona’s mail provider files spam into. A persona never answers mail in Junk. See Junk and spam. |
| Fault | A rule that makes SMTP misbehave on purpose. See Chaos and faults. |
| Insights | What happened to the mail you sent, per campaign. See Insights. |
| API key | A smk_… key for apps, CI and agents. One key works in one universe, with one role. See API keys. |
| Role | What someone may do: viewer, member, admin or owner. |
| Cell | One simmail server. All of an organization’s universes live on one cell, such as c1.simmail.dev. |
| AI action | One piece of AI work counted by your plan: a reply, inventing a person, writing a case story or an inbound email. |