---
title: "Understand Email Preflight"
description: "Learn what preflight checks and why it gates key actions."
canonical: "https://memo.ly/docs/understand-email-preflight"
updated: "2026-07-31"
---

# Understand Email Preflight

Learn what preflight checks and why it gates key actions.

**Who this is for:** Everyone shipping email through Memo.

**Preflight** is a deterministic, server-authoritative quality engine that runs on your compiled email output. It checks metadata, variables, links, assets, brand and footer rules, content, HTML and size, accessibility, and rendering.

## How findings work

- Blocking findings are enforced on the server and must be resolved.
- Warnings are surfaced in the UI but do not block.
- Quality profiles let a workspace tune non-critical thresholds; core checks stay immutable.
- Passing status is tied to a specific version’s content hash and rule-set version.

> Preflight gates approval, export, and test send. It fails closed: if it has not passed for a version, those actions are blocked.

## Expected result

You understand what preflight checks and why it matters.

## Related
- [Resolve preflight findings](https://memo.ly/docs/resolve-preflight-findings.md)
- [The email preflight checklist](https://memo.ly/email-preflight-checklist.md)
- [Glossary: Preflight](https://memo.ly/glossary/preflight.md)

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