Dependency

A dependency is a relationship between two pieces of work in which one cannot start or finish until the other does. In a product backlog, dependencies connect stories, tasks and bugs to each other or to things outside the team, such as an API another team owns or a vendor approval. They decide the order in which work can actually be delivered.

How Dependencies Work

Project management describes four logical types of dependency:

• Finish-to-start: B cannot start until A finishes. This is by far the most common, for example a database migration that must finish before the feature using it can be built.
• Start-to-start: B cannot start until A has started.
• Finish-to-finish: B cannot finish until A finishes.
• Start-to-finish: B cannot finish until A starts. This is rare.

Dependencies are also classified by control. Internal dependencies sit inside the team, while external ones rely on other teams, vendors or regulators. Some are mandatory because the logic requires the order. Others are discretionary: a preferred order the team could change.

In backlog tools, dependencies are usually recorded as links such as "blocks" and "is blocked by", so anyone can see why an item cannot start yet.

Why Dependencies Matter

Unseen dependencies are a common reason sprints miss their goals. An item that looks ready can stall on day three because it needs an endpoint another team has not built. Making dependencies visible during refinement lets the team reorder work, split items to remove the dependency or raise it with the other team early. Many teams include "no unresolved blocking dependencies" in their Definition of Ready.

Dependencies matter even more when AI coding agents execute work, because an agent will build whatever item it is given, whether its prerequisites exist or not. For a practical approach, see breaking epics into dependency-aware tasks.

Dependency Example

A story to let users pay by bank transfer depends on two other items: a task to add a payment-method field to the orders table, an internal finish-to-start dependency, and approval from the payment provider, an external dependency. The team links both as blockers, schedules the database task first and starts the approval request a sprint ahead.

Dependency vs. Roadmap Dependency

A dependency at backlog level links individual work items. A roadmap dependency links larger initiatives or releases on a roadmap, often across teams and over months.