Dependabot Configuration & Management

Overview

Dependabot is GitHub's built-in dependency management tool with three core capabilities:

1. Dependabot Alerts — Notify when dependencies have known vulnerabilities (CVEs)
2. Dependabot Security Updates — Auto-create PRs to fix vulnerable dependencies
3. Dependabot Version Updates — Auto-create PRs to keep dependencies current

All configuration lives in a single file: .github/dependabot.yml on the default branch. GitHub does not support multiple dependabot.yml files per repository.

Configuration Workflow

Follow this process when creating or optimizing a dependabot.yml:

Step 1: Detect All Ecosystems

Scan the repository for dependency manifests. Look for:

Ecosystem	YAML Value	Manifest Files
npm/pnpm/yarn	npm	package.json, package-lock.json, pnpm-lock.yaml, yarn.lock
pip/pipenv/poetry/uv	pip	requirements.txt, Pipfile, pyproject.toml, setup.py
Docker	docker	Dockerfile
Docker Compose	docker-compose	docker-compose.yml
GitHub Actions	github-actions	.github/workflows/*.yml
Go modules	gomod	go.mod
Bundler (Ruby)	bundler	Gemfile
Cargo (Rust)	cargo	Cargo.toml
Composer (PHP)	composer	composer.json
NuGet (.NET)	nuget	*.csproj, packages.config
.NET SDK	dotnet-sdk	global.json
Maven (Java)	maven	pom.xml
Gradle (Java)	gradle	build.gradle
Terraform	terraform	*.tf
OpenTofu	opentofu	*.tf
Helm	helm	Chart.yaml
Hex (Elixir)	mix	mix.exs
Swift	swift	Package.swift
Pub (Dart)	pub	pubspec.yaml
Bun	bun	bun.lockb
Dev Containers	devcontainers	devcontainer.json
Git Submodules	gitsubmodule	.gitmodules
Pre-commit	pre-commit	.pre-commit-config.yaml

Note: pnpm and yarn both use the npm ecosystem value.

Step 2: Map Directory Locations

For each ecosystem, identify where manifests live. Use directories (plural) with glob patterns for monorepos:

directories:
  - "/"           # root
  - "/apps/*"     # all app subdirs
  - "/packages/*" # all package subdirs
  - "/lib-*"      # dirs starting with lib-
  - "**/*"        # recursive (all subdirs)

Important: directory (singular) does NOT support globs. Use directories (plural) for wildcards.

Step 3: Configure Each Ecosystem Entry

Every entry needs at minimum:

- package-ecosystem: "npm"
  directory: "/"
  schedule:
    interval: "weekly"

Step 4: Optimize with Grouping, Labels, and Scheduling

See sections below for each optimization technique.

Monorepo Strategies

Glob Patterns for Workspace Coverage

For monorepos with many packages, use glob patterns to avoid listing each directory:

- package-ecosystem: "npm"
  directories:
    - "/"
    - "/apps/*"
    - "/packages/*"
    - "/services/*"
  schedule:
    interval: "weekly"

Cross-Directory Grouping

Use group-by: dependency-name to create a single PR when the same dependency updates across multiple directories:

groups:
  monorepo-deps:
    group-by: dependency-name

This creates one PR per dependency across all specified directories, reducing CI costs and review burden.

Limitations:

• All directories must use the same package ecosystem
• Applies to version updates only
• Incompatible version constraints create separate PRs

Standalone Packages Outside Workspaces

If a directory has its own lockfile and is NOT part of the workspace (e.g., scripts in .github/), create a separate ecosystem entry for it.

Dependency Grouping

Reduce PR noise by grouping related dependencies into single PRs.

By Dependency Type

groups:
  dev-dependencies:
    dependency-type: "development"
    update-types: ["minor", "patch"]
  production-dependencies:
    dependency-type: "production"
    update-types: ["minor", "patch"]

By Name Pattern

groups:
  angular:
    patterns: ["@angular*"]
    update-types: ["minor", "patch"]
  testing:
    patterns: ["jest*", "@testing-library*", "ts-jest"]

For Security Updates

groups:
  security-patches:
    applies-to: security-updates
    patterns: ["*"]
    update-types: ["patch", "minor"]

Key behaviors:

• Dependencies matching multiple groups go to the first match
• applies-to defaults to version-updates when absent
• Ungrouped dependencies get individual PRs

Multi-Ecosystem Groups

Combine updates across different package ecosystems into a single PR:

version: 2

multi-ecosystem-groups:
  infrastructure:
    schedule:
      interval: "weekly"
    labels: ["infrastructure", "dependencies"]

updates:
  - package-ecosystem: "docker"
    directory: "/"
    patterns: ["nginx", "redis"]
    multi-ecosystem-group: "infrastructure"

  - package-ecosystem: "terraform"
    directory: "/"
    patterns: ["aws*"]
    multi-ecosystem-group: "infrastructure"

The patterns key is required when using multi-ecosystem-group.

PR Customization

Labels

labels:
  - "dependencies"
  - "npm"

Set labels: [] to disable all labels including defaults. SemVer labels (major, minor, patch) are always applied if present in the repo.

Commit Messages

commit-message:
  prefix: "deps"
  prefix-development: "deps-dev"
  include: "scope"  # adds deps/deps-dev scope after prefix

Assignees and Milestones

assignees: ["security-team-lead"]
milestone: 4  # numeric ID from milestone URL

Branch Name Separator

pull-request-branch-name:
  separator: "-"  # default is /

Target Branch

target-branch: "develop"  # PRs target this instead of default branch

Note: When target-branch is set, security updates still target the default branch; all ecosystem config only applies to version updates.

Schedule Optimization

Intervals

Supported: daily, weekly, monthly, quarterly, semiannually, yearly, cron

schedule:
  interval: "weekly"
  day: "monday"         # for weekly only
  time: "09:00"         # HH:MM format
  timezone: "America/New_York"

Cron Expressions

schedule:
  interval: "cron"
  cronjob: "0 9 * * 1"  # Every Monday at 9 AM

Cooldown Periods

Delay updates for newly released versions to avoid early-adopter issues:

cooldown:
  default-days: 5
  semver-major-days: 30
  semver-minor-days: 7
  semver-patch-days: 3
  include: ["*"]
  exclude: ["critical-lib"]

Cooldown applies to version updates only, not security updates.

Security Updates Configuration

Enable via Repository Settings

Settings → Advanced Security → Enable Dependabot alerts, security updates, and grouped security updates.

Group Security Updates in YAML

groups:
  security-patches:
    applies-to: security-updates
    patterns: ["*"]
    update-types: ["patch", "minor"]

Disable Version Updates (Security Only)

open-pull-requests-limit: