Managing Migrations with Python + FastAPI: A Guide to Using Alembic and Comparing It with Laravel
FastAPI has gained popularity as a modern web framework for Python. To build a practical web application, database migration management is essential. A key tool for this in the Python ecosystem is Alembic.
In contrast, the PHP framework Laravel includes integrated migration features that allow schema management and rollbacks with ease.
This article offers a step-by-step guide to using Alembic with FastAPI, and compares it to Laravel’s migration system, highlighting pros, cons, and key considerations for each.
1. What Is Alembic? A Migration Tool for FastAPI and SQLAlchemy
Alembic is a migration tool for managing schema changes with SQLAlchemy. Since FastAPI often uses SQLAlchemy or SQLModel, integrating Alembic enables:
- Managing the history of table creation, modification, and deletion
- Version control (upgrade/downgrade)
- Sharing schema changes across development teams
2. Installing and Using Alembic with FastAPI
✅ Installing Alembic
pip install alembic
✅ Initializing Alembic
alembic init alembic
This creates an alembic/ directory and a config file alembic.ini.
✅ Editing the Configuration File
In alembic.ini, set your SQLAlchemy DB URL:
sqlalchemy.url = postgresql+asyncpg://user:password@localhost:5432/dbname
Also, in alembic/env.py, import your model definitions and pass Base.metadata to target_metadata to enable auto-migration:
from myapp.models import Base
target_metadata = Base.metadata
✅ Generating a Migration File (Auto-Detection)
alembic revision --autogenerate -m "create users table"
Alembic will detect changes and create a migration script.
✅ Applying Migrations (Upgrade)
alembic upgrade head
✅ Rolling Back Migrations (Downgrade)
alembic downgrade -1
3. Comparison with Laravel Migrations
| Feature | Alembic (FastAPI) | Laravel Migration |
|---|---|---|
| Integration Level | Requires setup as external tool | Built-in, fully integrated |
| Auto-generation | --autogenerate from models |
Manual schema definition |
| Framework Integration | Optional, works with FastAPI | Fully integrated with Laravel |
| Schema Visibility | Based on SQLAlchemy models | Explicit schema in code |
| Rollback Functionality | downgrade with specific version |
rollback, reset are easy |
| Test DB Management | Requires manual setup | migrate:fresh and more |
| File Structure | Managed in versions/ folder |
Unified under database/migrations/ |
4. Pros and Cons of Alembic
✅ Pros
- Auto-generates schema from SQLAlchemy models
- Allows flexible manual migration editing
- Complex logic can be written in Python
- Version control is easy to share in teams
❌ Cons
- Initial setup takes more effort
- Extra care needed for async DB support (e.g., with SQLModel or SQLAlchemy 2.x)
- Not as seamless as Laravel’s built-in migration system
5. Key Differences to Watch Out For When Coming from Laravel
1. Level of Automation
Laravel integrates migrations, models, factories, and seeders. In FastAPI, migrations are managed separately, so developers must clearly organize schema management.
2. Rollback Strategy
Laravel’s migrate:rollback is simple, but Alembic requires explicit versioning, demanding more precise control.
3. Migration File Granularity
In Laravel, one file typically maps to one table. In Alembic, a single migration file can contain multiple operations—naming conventions and management standards are key for team collaboration.
6. Conclusion: FastAPI + Alembic Is a Flexible and Powerful Choice
While Alembic may seem complex at first, it’s a powerful and flexible tool for Python developers. When combined with FastAPI, it enables scalable and reliable schema version control.
✔️ Summary of Alembic Benefits:
- Seamless integration with SQLAlchemy models
- Flexible migration scripting and version management
- Suitable for collaborative development workflows