# Behavior

> The deterministic logic Reply applies — what triggers each behavior, what changes as a result, and which exceptions exist. Each behavior is one page.

_Status: Reviewed — human-edited, facts not yet confirmed against the product._

Behavior pages answer the questions agents and operators actually ask mid-build: *what
stops a sequence? which mailbox sends this email? what happens after a bounce?* Every
behavior page states its trigger, decision logic, result, state changes, and exceptions —
grounded in Reply's product documentation, with exact thresholds, setting names, and
status enums — so behavior is predictable before you rely on it.

## Enrollment and data

- [How contacts enter a sequence](/behavior/contact-enrollment) — enrollment paths, checks, and conflicts
- [How Reply detects duplicate contacts](/behavior/contact-deduplication) — the identifier key, and import handling

## Execution and sending

- [How a sequence executes](/behavior/sequence-execution) — step order, delays, limits, health
- [When Reply sends](/behavior/sending-schedules) — schedule windows meet delays and budgets
- [How Reply selects a sending mailbox](/behavior/mailbox-selection) — distribution across assigned accounts

## Replies and state

- [How Reply detects replies](/behavior/reply-detection) — matching, classification, stopping
- [What happens when an email bounces](/behavior/bounce-handling) — bounce state and protection
- [When Reply stops a sequence](/behavior/sequence-stopping) — every stop condition in one place
- [How statuses change](/behavior/status-transitions) — the transition matrix
- [How statistics are calculated](/behavior/statistics-calculation) — counters and denominators

## Planned

| Page | Status |
| --- | --- |
| Step execution detail | Not written |
| Daily sending limits (cross-object precedence) | Not written |
| Automatic-reply detection | Not written |
| Unsubscribe handling | Not written |
| Conversation matching | Not written |
| Task generation | Not written |
| Credit consumption | Not written |

## Related

- [Specifications](/specifications) — the objects these rules move
- [Troubleshooting](/troubleshooting) — when observed behavior doesn't match a rule

## Build with Reply

- REST API: [docs.reply.io](https://docs.reply.io/api-reference/introduction) — the operations that trigger these rules