Events reference
All eight event types, what each one means, and what evidence comes with it.
Everything that happens to a message becomes an event, stored with the receiving provider’s original payload alongside our normalised version. This page is what each type means.
The eight types
| Type | State | Meaning |
|---|---|---|
delivery | good | The receiving provider accepted the message. |
bounce | bad | Delivery failed. bounce_type is Permanent or Transient. |
delivery_delay | warning | Deferred — the provider asked us to try again later. |
complaint | bad | The recipient reported the message as spam. |
open | neutral | Tracking pixel loaded. Optional, per domain. |
click | neutral | A tracked link was followed. Optional, per domain. |
reject | bad | Refused before leaving OutSend. |
rendering_failure | bad | Template variables did not resolve. |
Why delivery is not delivered
A delivery event means the receiving server accepted the message. It does not mean the
message reached an inbox. It could be in a spam folder, in a quarantine, or silently
discarded by a filter that will never tell anyone.
This distinction is why we keep the provider’s response rather than collapsing everything
into a percentage. 250 2.0.0 OK is a fact you can act on. “98.7% delivered” is a summary
of facts you cannot see.
Systematic inbox-placement measurement is on our roadmap, and it will arrive with its methodology published. Until then, we will not print a placement number we cannot show you the method for.
Bounces
- Permanent — the address does not exist, or the domain refuses you outright. The address is suppressed automatically. Do not retry these; retrying permanent bounces is one of the fastest ways to damage a sending reputation.
- Transient — a full mailbox, a temporary block, a greylist. These often resolve.
Deferrals
A delivery_delay is the provider telling you to slow down. Concentrated deferrals at one
provider usually means a reputation signal rather than an addressing problem, and the
response text normally says which. This is the event most platforms hide, and it is the
most useful early warning you get.
Rejections
A reject means OutSend refused to send: a suppressed address, an unverified from
domain, a disabled workspace. Rejected messages are visible in the log and are not billed.
Getting at them
- In the dashboard — filter by type, recipient, and date range.
- Over webhooks — pushed as they happen. See Webhooks.
- Retention — 30 days to 12 months depending on plan, configurable on Dedicated.