Why Choose
Flask?

The right tool for most web applications

Flask is not the most powerful framework. It's the most honest one.

Django gives you an admin interface out of the box. FastAPI gives you automatic API docs. Express gives you the JavaScript ecosystem. But Flask gives you something more valuable: transparency. And in the age of AI-assisted development, you can build a custom admin panel in hours—tailored exactly to your needs, not a generic default.

In 2026, with AI writing half your code, you need a framework that gets out of the way. Flask is a routing layer, a template engine, and nothing else. What you write is what runs.

Framework Comparison

Choosing the right backend framework in 2026

Feature Flask Django FastAPI Express
Setup Time 30 seconds 5 minutes 2 minutes 1 minute
Lines for "Hello World" 5 lines 15+ lines 7 lines 6 lines
Database Approach Your choice (SQL) ORM required Your choice Your choice
Built-in Admin No Yes No No
API Documentation Manual Manual Automatic Manual
Template Engine Jinja2 (excellent) Django templates None (API-first) Your choice
Learning Curve 1 day 2 weeks 3 days 2 days
AI Coding Success Rate 95% 75% 90% 85%
Performance (req/sec) 3,000 2,000 5,000 4,000
Best For Most web apps Content-heavy sites APIs Real-time apps

The Verdict

Flask wins for simplicity and AI-friendliness. Django's built-in admin is convenient, but with AI assistance, Flask lets you build custom admin panels in hours—perfectly fitted to your use case. FastAPI wins for pure APIs with automatic docs. Express wins if you're already in the Node.js ecosystem.

Decision Matrix

Choose the right framework for your project

Choose Flask When...

  • You're building a web app (not just an API)
  • You want full control over your database queries
  • You value simplicity over built-in features
  • You want to understand every line of code
  • You're using AI assistants for development
  • You need fast page loads (HTML over JSON)
  • You're a solo developer or small team
  • You're learning web development

Choose Django When...

  • You're building a CMS or content-heavy site
  • You have a large team with defined conventions
  • You're in an enterprise environment
  • You want built-in security patterns
  • You prefer "batteries included" philosophy
  • You're comfortable with ORMs
  • Your team is already experienced with Django
  • You prefer default admin over custom-built solutions

Choose FastAPI When...

  • You're building a pure REST/GraphQL API
  • You want automatic API documentation
  • Type safety is critical (Pydantic validation)
  • You have separate frontend (React, Vue, mobile)
  • Raw performance is top priority
  • You need async/await for real-time features
  • You're building microservices
  • You love modern Python features

Choose Express When...

  • Your team only knows JavaScript
  • You need WebSockets/real-time features
  • You're deploying to Vercel/Netlify
  • You're using Next.js and need custom API routes
  • You want to share code between frontend/backend
  • You need Node.js streams/event handling
  • You're using npm packages for everything
  • You're building a proxy/middleware layer

"But... Is Flask Still Relevant?"

The four objections we hear most — answered directly.

"Flask is old technology. Everyone's moved on."

Flask was released in 2010. PostgreSQL in 1996. The web still runs on both. Maturity is a feature, not a defect.

Flask consistently tops Python's most-used web framework surveys and gets 10+ million PyPI downloads per month as of 2026. Instagram and Pinterest were built on Flask. Airbnb, Lyft, and Netflix have used it in production. "Old" means stable, documented, and battle-tested.

The framework your grandchildren will be able to maintain is more valuable than the framework that's trending today.

"FastAPI is the new Flask. You should use that instead."

FastAPI is excellent — we recommend it on this very page for API-only projects. But FastAPI is built for APIs, not for web applications. It has no templating system. It doesn't serve HTML pages.

If you're building a web application — routes, HTML pages, forms, a user interface — Flask is still the better fit. FastAPI and Flask are not competing for the same job.

FastAPI wins for pure APIs. Flask wins for web apps. Both win over ORMs.

"Flask doesn't support async. It can't scale."

Flask has supported async route handlers since Flask 2.0 (2021). And for the vast majority of web apps that are standard CRUD — querying a database, rendering a template, sending an email — synchronous code with a proper WSGI server (gunicorn + gevent) scales comfortably to thousands of concurrent requests.

Instagram served 500M users on Django (synchronous Python). The bottleneck is almost never the framework. It's unoptimised database queries and missing caches.

Fix your N+1 queries before blaming your framework for scale issues.

"Python has no type safety. TypeScript is safer."

Python has had type hints since 3.5 and a first-class type checker (mypy, pyright) since well before TypeScript became mainstream. You can add as much type safety to a Flask app as you want.

But more importantly: in an AI-assisted development workflow, the verification loop matters more than static types. A Flask route with raw SQL that you can read and know is correct is safer in practice than a TypeScript + Prisma chain where the generated SQL is invisible. See the verification gap →

Readability is the best type system.

When NOT to Use Flask

Flask isn't the answer to everything. Here's when to choose something else.

Your site is purely presentational — no backend needed at all

If you're building a portfolio, landing page, event page, or docs site with no database and no user accounts, you don't need Flask — you don't need any backend. A plain index.html + styles.css deployed on Netlify via GitHub is faster, cheaper, and simpler. Free HTTPS, global CDN, auto-deploy on every git push. See our guide to static sites →

You prefer generic defaults over custom-built solutions

Django's admin interface is excellent if you're okay with its defaults. However, with AI-assisted coding in 2026, building a custom admin panel in Flask takes just a few hours—and you get exactly what you need, not a one-size-fits-all solution. If you prefer convention over customization, Django is still a solid choice.

You're building a pure API with complex validation

For REST/GraphQL APIs with heavy Pydantic validation and automatic OpenAPI docs, use FastAPI. Flask can do it, but FastAPI is purpose-built for this and gives you auto-generated docs + type safety for free.

Your team is 100% JavaScript

If nobody on your team knows Python and you need to ship fast, use Express.js. Don't force Python on a JavaScript team. The context-switching overhead will kill you.

You need heavy real-time features (WebSockets, SSE)

Flask can handle WebSockets via Flask-SocketIO, but it's not its strength. For chat apps, live dashboards, or real-time collaboration, consider FastAPI (with async) or Node.js (event-driven architecture).

You're building the next Netflix or Uber

At massive scale (100M+ requests/day), you need specialized infrastructure. Flask works great at scale with proper caching and CDN, but you'll eventually need microservices, Kubernetes, and a polyglot architecture. At that level, framework choice matters less than infrastructure.

You love heavy abstractions and magic

If you prefer frameworks that "do the thinking for you" and hide complexity, you'll find Flask frustrating. It's explicit and minimalist. If you want more magic, try Django or Ruby on Rails.

Honest Assessment

"Flask is my default for every project. I've never felt the need to reach for something else. When people ask me 'but what about Django's admin?' I tell them: with AI, I build exactly what I need in a few hours. No bloat, no conventions to fight."
— Frederick Tubiermont

Flask: The 80% Solution

Most web applications are simpler than you think

What is an "80% web app"?

Most web applications are CRUD apps with authentication, a database, and some business logic. They're not Google. They're:

  • SaaS dashboards (project management, CRM, analytics)
  • Internal tools (admin panels, reporting, data entry)
  • E-commerce sites (catalogs, carts, checkout)
  • Content sites (blogs, portfolios, documentation)
  • MVPs and prototypes (validate ideas fast)
  • Small business websites (restaurants, agencies, services)

For these apps, Flask is the perfect choice. It's fast, transparent, and AI-friendly.

80%

of web apps are CRUD

Create, Read, Update, Delete + Auth

15%

need specialized tools

APIs, real-time, admin-heavy

5%

need custom architecture

Massive scale, unique requirements

Ready to Choose Flask?

Start building transparent, AI-friendly web applications today.

Start Learning Flask See Full Comparison