Dependabot

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:

Notes:

• pnpm and yarn both use the npm ecosystem value.
• Prefer uv ecosystem value when uv.lock is present; otherwise use pip.

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: 0  # disables version update PRs

Auto-Triage Rules

GitHub presets auto-dismiss low-impact alerts for development dependencies. Custom rules can filter by severity, package name, CWE, and more. Configure in repository Settings → Advanced Security.

PR Comment Commands

Interact with Dependabot PRs using @dependabot comments.

Note: As of January 2026, merge/close/reopen commands have been deprecated. Use GitHub's native UI, CLI (gh pr merge), or auto-merge instead.

For grouped PRs, additional commands:

• @dependabot ignore DEPENDENCY_NAME — ignore specific dependency in group
• @dependabot unignore DEPENDENCY_NAME — clear ignores, reopen with updates
• @dependabot unignore * — clear all ignores for all dependencies in group
• @dependabot show DEPENDENCY_NAME ignore conditions — display current ignores

For the complete command reference, see references/pr-commands.md.