Dependency Map Template

What this template is for

A dependency map template helps engineering teams see which systems rely on which other systems before a change, outage, or migration. This template groups nodes into presentation, API, domain, and data layers, then connects apps, gateways, services, databases, cache, and search indexes. Use it to plan refactors, review blast radius, onboard engineers, or document architecture that has grown beyond what one person can hold in their head.

When to use this template

• Estimate the blast radius of changing an API, service, database, or cache.
• Document dependencies before a refactor or platform migration.
• Onboard new engineers by showing which application layers call each other.
• Find hidden coupling between frontends, BFFs, public APIs, and domain services.
• Plan service ownership changes by making upstream and downstream dependencies visible.

How to use it

1. 1List the layers in order: presentation, API, domain, and data.
2. 2Add the main applications, gateways, services, and storage systems in their layers.
3. 3Draw arrows from each consumer to the dependency it calls or reads from.
4. 4Use dashed lines for optional or indirect dependencies.
5. 5Review each dependency and ask whether it is required, accidental, or outdated.
6. 6Add notes for high-risk dependencies such as shared databases or synchronous chains.

Quick example