# Merge Queue Academy

> Educational documentation about merge queues—systems that serialize and validate pull requests before they land on main. Learn how merge queues keep your main branch stable while enabling high-velocity development.

Merge queues solve a fundamental problem: pull requests that pass CI individually can break main when merged together. A merge queue tests each PR against its actual merge target—including all PRs ahead of it—guaranteeing main stays green.

## Introduction

- [What is a Merge Queue?](/introduction/what-is-a-merge-queue/): How merge queues keep your main branch stable while teams ship fast.
- [How Merge Queues Work](/introduction/how-merge-queues-work/): The mechanics and lifecycle of a PR in a merge queue.
- [Companies Using Merge Queues](/introduction/companies-using-merge-queues/): Real examples of companies using merge queues at scale, with public sources.

## Do You Need One?

- [What Happens Without a Merge Queue](/decision/failure-scenarios/): The failure modes and cascading costs of broken main branches.
- [Do You Need a Merge Queue?](/decision/quiz/): A quick assessment to help you decide if a merge queue is right for your team.
- [When to Skip It](/decision/when-to-skip-it/): When a merge queue isn't the right choice - small teams, low volume, simple repos.
- [Prerequisites](/decision/prerequisites/): What to fix before adopting a merge queue - flaky tests, CI reliability, and failure rates.
- [Making the Case](/decision/making-the-case/): How to convince your team, manager, or leadership that you need a merge queue.
- [Final Quiz](/decision/final-quiz/): Test your merge queue knowledge with this 12-question challenge. Earn your diploma!

## Features

- [Two-Step CI](/features/two-step-ci/): Separate PR validation from queue validation for safer merges.
- [Batching](/features/batching/): Test multiple PRs together for efficiency.
- [Speculative Checks](/features/speculative-merging/): Parallelize testing by assuming earlier PRs will pass.
- [Parallel Queues](/features/parallel-queues/): Independent queues for non-conflicting changes.
- [Freshness Policies](/features/freshness-policies/): Balance safety and throughput with configurable freshness requirements.
- [Priority Management](/features/priority-management/): Urgent PRs can jump the queue.

## Use Cases

- [Monorepos](/use-cases/monorepos/): Managing merge queues for large repositories with many teams and independent components.
- [High-Velocity Teams](/use-cases/high-velocity-teams/): Merge queues for teams shipping 20+ PRs per day.
- [Long CI Pipelines](/use-cases/long-ci-pipelines/): Optimizing merge queues when CI takes 30+ minutes.

## glossary

- [Glossary](/glossary/): Key terms and concepts used throughout Merge Queue Academy.