Django Safe Migrations

Detect unsafe Django migrations before they break production.

What is Django Safe Migrations?

Django Safe Migrations is a static analysis tool for Django migrations. It scans your migrations and warns you about operations that could cause:

• Table locks that block reads/writes
• Downtime during deployments
• Data loss from unsafe drops
• Application errors from schema/code mismatches

Quick Example

$ python manage.py check_migrations

Found 1 migration issue(s):

ERROR [SM001] myapp/migrations/0002_add_email.py:15
   Adding NOT NULL field 'email' to 'user' without a default value will lock the table
   Operation: AddField(user.email)

   Suggestion:
      1. Add field as nullable first
      2. Backfill existing rows
      3. Add NOT NULL constraint in separate migration

Why Use This?

Without Safe Migrations	With Safe Migrations
Deploy, find out table is locked for 10 minutes	Get warned before merge
Roll back, scramble to fix	Fix with suggested pattern
Angry users, lost revenue	Happy users, smooth deploy

Features

• 47 built-in rules covering schema changes, locking, data loss, and best practices
• Database-aware rules, including PostgreSQL-specific checks for concurrent indexes, TEXT vs VARCHAR, and IDENTITY columns, plus MySQL- and SQLite-specific categories
• Fix suggestions with safe migration patterns for every issue
• CI/CD ready — GitHub Actions, GitLab Code Quality, JSON, SARIF output
• Fast — static analysis without running migrations
• Baseline support — suppress existing issues, catch only new ones
• Diff mode — only check migrations changed since a branch
• Interactive mode — review and triage issues one-by-one
• Watch mode — re-run on file changes during development

Getting Started

pip install django-safe-migrations

Then check out the Installation and Quick Start guides.