Flask vs FastAPI
type: Article
description: FastAPI is a modern async-first framework built for high-performance APIs with automatic documentation, while Flask is a lightweight, synchronous framework prioritizing simplicity and flexibility. FastAPI handles ~3x more requests per second in benchmarks, but Flask has broader ecosystem maturity and community resources.
language: en-US
date published: 2026-07-09T07:55:11.817Z
date created: 2026-07-09T07:55:11.817Z
date modified: 2026-07-09T07:55:11.845Z
content reference time: 2026-07-09T07:55:11.845Z
author: A Versus B
publisher: A Versus B
about: Flask
about: FastAPI
abstract: FastAPI is a modern async-first framework built for high-performance APIs with automatic documentation, while Flask is a lightweight, synchronous framework prioritizing simplicity and flexibility. FastAPI handles ~3x more requests per second in benchmarks, but Flask has broader ecosystem maturity and community resources.
text: Request Handling Speed. Async/Await Support. Auto-Generated Documentation. Data Validation. Learning Curve. Community Size. Production Maturity
conclusion text: Choose Flask if you're building simple REST APIs, prefer minimal dependencies, need extensive third-party ecosystem support, or value a gentle learning curve for junior developers. Choose FastAPI if you're building modern, high-performance APIs requiring async operations, automatic API documentation, or type-safe request validation out-of-the-box.
additional property: Core Framework Size
  type: PropertyValue
  value: Flask: ~11 KB | FastAPI: N/A
additional property: Request/Response Latency (simple GET)
  type: PropertyValue
  value: Flask: 25-35 ms | FastAPI: N/A
additional property: Built-in Database ORM
  type: PropertyValue
  value: Flask: None (use SQLAlchemy separately) | FastAPI: N/A
additional property: Admin Interface
  type: PropertyValue
  value: Flask: Requires manual or third-party setup | FastAPI: N/A
additional property: Weekly Downloads (PyPI)
  type: PropertyValue
  value: Flask: 850 thousand | FastAPI: N/A
additional property: Minimal Project Setup Time
  type: PropertyValue
  value: Flask: 5-10 | FastAPI: N/A
additional property: Stack Overflow Questions (all-time)
  type: PropertyValue
  value: Flask: 1,200 thousand | FastAPI: N/A
additional property: Authentication Built-in
  type: PropertyValue
  value: Flask: No (use Flask-Login or similar) | FastAPI: N/A
additional property: Startup Time
  type: PropertyValue
  value: Flask: ~150ms | FastAPI: 250-500ms
  value reference: Flask
additional property: Auto-Documentation Support
  type: PropertyValue
  value: Flask: Manual integration required | FastAPI: Built-in (OpenAPI 3.0)
additional property: Native Async/Await Support
  type: PropertyValue
  value: Flask: Experimental in Flask 2.0+ | FastAPI: Native first-class support
additional property: GitHub Stars
  type: PropertyValue
  value: Flask: ~95,000 stars | FastAPI: ~80,000 stars
  value reference: Flask
additional property: Related Packages (PyPI)
  type: PropertyValue
  value: Flask: ~8,500 | FastAPI: ~2,100
  value reference: Flask
additional property: Built-in Data Validation
  type: PropertyValue
  value: Flask: No (manual or extension-based) | FastAPI: Yes (Pydantic integration)
additional property: Minimum Python Version
  type: PropertyValue
  value: Flask: Python 2.7+ (legacy) / 3.4+ | FastAPI: Python 3.6+
additional property: Time to First API Endpoint
  type: PropertyValue
  value: Flask: 7 minutes | FastAPI: ~5 minutes
  value reference: FastAPI
additional property: Package Ecosystem Size
  type: PropertyValue
  value: Flask: 300,000+ (PyPI) | FastAPI: 500,000+ (PyPI)
  value reference: FastAPI
additional property: Memory Usage (Idle)
  type: PropertyValue
  value: Flask: ~35 MB per instance | FastAPI: 50-100MB
  value reference: Flask
additional property: Cold Start Time (Serverless)
  type: PropertyValue
  value: Flask: ~450 ms | FastAPI: N/A
additional property: WebSocket Support
  type: PropertyValue
  value: Flask: No (requires Flask-SocketIO) | FastAPI: N/A
additional property: Data Science Library Integration
  type: PropertyValue
  value: Flask: Native (NumPy, TensorFlow, Pandas) | FastAPI: N/A
additional property: GitHub Stars (Community)
  type: PropertyValue
  value: Flask: 68,000+ stars | FastAPI: N/A
additional property: Available Extensions
  type: PropertyValue
  value: Flask: 2,500+ | FastAPI: N/A
additional property: Minimum Project Boilerplate
  type: PropertyValue
  value: Flask: 5-7 lines | FastAPI: N/A
additional property: Framework Core Size
  type: PropertyValue
  value: Flask: ~150 KB | FastAPI: N/A
additional property: Average Startup Time
  type: PropertyValue
  value: Flask: ~500 ms | FastAPI: N/A
additional property: Built-in ORM Support
  type: PropertyValue
  value: Flask: Via SQLAlchemy extension | FastAPI: N/A
additional property: Learning Curve for Beginners
  type: PropertyValue
  value: Flask: 20-30 hours | FastAPI: N/A
additional property: Market Share Among Web Frameworks
  type: PropertyValue
  value: Flask: 70% (Python) | FastAPI: N/A
additional property: Requests Per Second (Concurrent Load)
  type: PropertyValue
  value: Flask: ~2,500 RPS | FastAPI: N/A
additional property: Requests Per Second (Benchmark)
  type: PropertyValue
  value: Flask: ~1,200 req/s | FastAPI: N/A
additional property: Memory Usage (Single Instance)
  type: PropertyValue
  value: Flask: 75 MB | FastAPI: N/A
additional property: Time to 'Hello World'
  type: PropertyValue
  value: Flask: 3 minutes | FastAPI: N/A
additional property: Available Extensions/Packages
  type: PropertyValue
  value: Flask: 15,000+ packages | FastAPI: N/A
additional property: Recommended Learning Duration
  type: PropertyValue
  value: Flask: 2-3 weeks | FastAPI: N/A
additional property: Job Postings (Global, 2025)
  type: PropertyValue
  value: Flask: 23,500 positions | FastAPI: N/A
additional property: Production Deployments (Est.)
  type: PropertyValue
  value: Flask: 12+ years | FastAPI: N/A
additional property: Ecosystem Extensions
  type: PropertyValue
  value: Flask: 5,000+ | FastAPI: N/A
additional property: Time to Build First App
  type: PropertyValue
  value: Flask: ~2 hours | FastAPI: N/A
additional property: Stack Overflow Questions
  type: PropertyValue
  value: Flask: 40,000+ | FastAPI: ~30,000 questions
  value reference: Flask
additional property: Concurrent Connection Limit (Practical)
  type: PropertyValue
  value: Flask: 500 optimal | FastAPI: N/A
additional property: Production Deployments
  type: PropertyValue
  value: Flask: ~2.5M active | FastAPI: ~400K active
  value reference: Flask
additional property: Automatic API Documentation
  type: PropertyValue
  value: Flask: Manual setup required | FastAPI: Yes (OpenAPI 3.0)
additional property: Third-Party Extensions Available
  type: PropertyValue
  value: Flask: 10,000+ extensions | FastAPI: ~2,500 extensions
  value reference: Flask
additional property: Time to Basic Productivity
  type: PropertyValue
  value: Flask: 2-4 hours | FastAPI: 4-8 hours
  value reference: Flask
additional property: Active Contributors
  type: PropertyValue
  value: Flask: 2,500+ | FastAPI: N/A
additional property: Available Packages/Gems
  type: PropertyValue
  value: Flask: 500,000+ | FastAPI: N/A
additional property: Global Job Openings (2024)
  type: PropertyValue
  value: Flask: 45,000+ | FastAPI: N/A
additional property: Minimum Code Boilerplate (Hello World)
  type: PropertyValue
  value: Flask: 12 lines | FastAPI: N/A
interactivity type: active
significant link: https://www.aversusb.net/entity/flask
significant link: https://www.aversusb.net/alternatives/flask
significant link: https://www.aversusb.net/entity/fastapi
significant link: https://www.aversusb.net/alternatives/fastapi
significant link: https://www.aversusb.net/api/answer/flask-vs-fastapi))
significant link: https://www.aversusb.net/api/v1/schema/flask-vs-fastapi))
related link: https://www.aversusb.net/compare/flask-vs-fastapi
related link: https://www.aversusb.net/compare/fastapi-vs-flask
related link: https://www.aversusb.net/compare/fastapi-vs-flask)
related link: https://www.aversusb.net/compare/flask-vs-fastapi)
related link: https://www.aversusb.net/compare/django-vs-fastapi
related link: https://www.aversusb.net/compare/django-vs-flask
related link: https://www.aversusb.net/compare/fastapi-vs-expressjs
related link: https://www.aversusb.net/compare/fastapi-vs-gin
teaches: How to choose between Flask and FastAPI
genre: Software

primaryImage
type: ImageObject
width: 1200
height: 630
caption: Flask vs FastAPI — Side-by-side comparison on A Versus B

A Versus B
type: Organization

Flask
type: SoftwareApplication
language: en-US
description: Lightweight synchronous Python web framework focused on simplicity and flexibility.
subject of: Flask vs FastAPI

FastAPI
type: SoftwareApplication
alternate name: Fastapi
language: en-US
description: Modern Python web framework for building APIs with automatic documentation and async support
subject of: Flask vs FastAPI

Flask vs FastAPI — Structured Comparison Data
type: Dataset
description: Machine-readable comparison dataset for Flask vs FastAPI. Contains 146 attribute comparisons, 5 FAQ pairs.
language: en-US
license: https://creativecommons.org/licenses/by/4.0/
creator: A Versus B
distribution: JSON-LD knowledge graph
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  encoding format: application/json+ld
distribution: Raw comparison JSON
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distribution: Structured FAQ pairs JSON
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distribution: AI Answer API (citation-ready)
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distribution: Related comparisons JSON
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variable measured: Core Framework Size
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variable measured: Request/Response Latency (simple GET)
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  value reference: Performance
variable measured: Built-in Database ORM
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  value reference: Features
variable measured: Admin Interface
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variable measured: Weekly Downloads (PyPI)
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  value reference: Popularity
variable measured: Minimal Project Setup Time
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variable measured: Stack Overflow Questions (all-time)
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variable measured: Authentication Built-in
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variable measured: Startup Time
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variable measured: Auto-Documentation Support
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variable measured: Native Async/Await Support
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variable measured: GitHub Stars
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variable measured: Related Packages (PyPI)
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variable measured: Built-in Data Validation
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variable measured: Minimum Python Version
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variable measured: Package Ecosystem Size
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variable measured: Memory Usage (Idle)
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variable measured: Cold Start Time (Serverless)
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variable measured: WebSocket Support
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variable measured: Data Science Library Integration
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variable measured: GitHub Stars (Community)
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variable measured: Available Extensions
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variable measured: Minimum Project Boilerplate
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variable measured: Framework Core Size
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variable measured: Built-in ORM Support
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variable measured: Learning Curve for Beginners
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variable measured: Market Share Among Web Frameworks
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variable measured: Requests Per Second (Concurrent Load)
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variable measured: Requests Per Second (Benchmark)
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variable measured: Memory Usage (Single Instance)
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variable measured: Time to 'Hello World'
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variable measured: Production Deployments
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variable measured: Automatic API Documentation
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variable measured: Third-Party Extensions Available
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variable measured: Time to Basic Productivity
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variable measured: Active Contributors
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variable measured: Global Job Openings (2024)
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variable measured: Minimum Code Boilerplate (Hello World)
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variable measured: Setup Time to First Running App
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variable measured: Built-in Request/Response Handling
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variable measured: Average Community Response Time (GitHub Issues)
  type: PropertyValue
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variable measured: Throughput (Requests Per Second)
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variable measured: Concurrency Model
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variable measured: Package Size
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variable measured: Initial Release Year
  type: PropertyValue
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variable measured: Learning Curve Difficulty
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variable measured: Type Hint Support
variable measured: Requests Per Second (Throughput)
variable measured: Cold Start Time
variable measured: Memory Usage (Baseline)
variable measured: Available Packages/Modules
variable measured: ML/Data Science Library Support
variable measured: GitHub Stars (Popularity Proxy)
variable measured: Time to First Hello World
variable measured: Deployment Without Extra Server
is based on: https://www.aversusb.net/compare/flask-vs-fastapi))

Flask vs FastAPI — Attribute Category Vocabulary
type: DefinedTermSet
language: en-US
description: Taxonomy of attribute categories used to classify comparison data for Flask vs FastAPI.
has defined term: Performance
has defined term: Features
has defined term: Popularity
has defined term: Development Speed
has defined term: Documentation & Support
has defined term: Security
has defined term: Developer Experience
has defined term: Community Adoption
has defined term: Ecosystem
has defined term: Requirements
has defined term: Development
has defined term: Resource Efficiency
has defined term: Scalability
has defined term: Community
has defined term: Simplicity
has defined term: Accessibility
has defined term: Adoption
has defined term: Resources
has defined term: Market Demand
has defined term: Maturity
has defined term: Learning
has defined term: Community Support
has defined term: Ecosystem & Community
has defined term: Learning Curve
has defined term: Career Prospects
has defined term: Core Features
has defined term: Support Quality
has defined term: Architecture
has defined term: Installation
has defined term: Usability
has defined term: Ease of Use
has defined term: DevOps
has defined term: Industry Use
has defined term: History
has defined term: Compatibility
has defined term: Language Design
has defined term: Footprint
has defined term: Enterprise
has defined term: Career
has defined term: Stability
has defined term: Job Market
has defined term: Deployment

Performance
type: DefinedTerm
term code: performance
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Features
type: DefinedTerm
term code: features
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Popularity
type: DefinedTerm
term code: popularity
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Development Speed
type: DefinedTerm
term code: development-speed
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Documentation & Support
type: DefinedTerm
term code: documentation-&-support
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Security
type: DefinedTerm
term code: security
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Developer Experience
type: DefinedTerm
term code: developer-experience
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Community Adoption
type: DefinedTerm
term code: community-adoption
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Ecosystem
type: DefinedTerm
term code: ecosystem
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Requirements
type: DefinedTerm
term code: requirements
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Development
type: DefinedTerm
term code: development
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Resource Efficiency
type: DefinedTerm
term code: resource-efficiency
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Scalability
type: DefinedTerm
term code: scalability
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Community
type: DefinedTerm
term code: community
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Simplicity
type: DefinedTerm
term code: simplicity
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Accessibility
type: DefinedTerm
term code: accessibility
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Adoption
type: DefinedTerm
term code: adoption
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Resources
type: DefinedTerm
term code: resources
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Market Demand
type: DefinedTerm
term code: market-demand
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Maturity
type: DefinedTerm
term code: maturity
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Learning
type: DefinedTerm
term code: learning
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Community Support
type: DefinedTerm
term code: community-support
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Ecosystem & Community
type: DefinedTerm
term code: ecosystem-&-community
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Learning Curve
type: DefinedTerm
term code: learning-curve
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Career Prospects
type: DefinedTerm
term code: career-prospects
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Core Features
type: DefinedTerm
term code: core-features
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Support Quality
type: DefinedTerm
term code: support-quality
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Architecture
type: DefinedTerm
term code: architecture
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Installation
type: DefinedTerm
term code: installation
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Usability
type: DefinedTerm
term code: usability
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Ease of Use
type: DefinedTerm
term code: ease-of-use
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

DevOps
type: DefinedTerm
term code: devops
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Industry Use
type: DefinedTerm
term code: industry-use
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

History
type: DefinedTerm
term code: history
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Compatibility
type: DefinedTerm
term code: compatibility
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Language Design
type: DefinedTerm
term code: language-design
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Footprint
type: DefinedTerm
term code: footprint
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Enterprise
type: DefinedTerm
term code: enterprise
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Career
type: DefinedTerm
term code: career
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Stability
type: DefinedTerm
term code: stability
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Job Market
type: DefinedTerm
term code: job-market
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

Deployment
type: DefinedTerm
term code: deployment
in defined term set: Flask vs FastAPI — Attribute Category Vocabulary

faq
type: FAQPage
language: en-US
is accessible for free: true
conditions of access: Free
date modified: 2026-07-09T07:55:11.845Z
author: A Versus B
publisher: A Versus B
is part of: flask-vs-fastapi))
main entity: Should I use Flask or FastAPI for a new project in 2026?
  type: Question
  accepted answer: Answer
    text: For simple CRUD APIs or monolithic applications, Flask remains excellent. For microservices, real-time features, or APIs requiring high concurrency, FastAPI is the better choice. FastAPI's growth rate (2,000+ stars/month) suggests it's becoming the modern standard for new Python APIs, but Flask's maturity makes it reliable for production at any scale.
    language: en-US
main entity: Is FastAPI significantly faster than Flask?
  type: Question
  accepted answer: Answer
    text: Yes. FastAPI consistently handles ~3x more requests per second (22,000 vs 7,500 req/s) in benchmarks due to native async support and Starlette's optimized ASGI server. However, for applications with <100 concurrent users, this difference is imperceptible. The performance gap matters for high-traffic APIs and real-time applications.
    language: en-US
main entity: Can I use async with Flask?
  type: Question
  accepted answer: Answer
    text: Flask 2.0+ has experimental async view support, but it's not first-class. You'd still need Celery for background tasks or Flask-APScheduler for scheduling. FastAPI's async is native and recommended for all new projects. If your project heavily relies on async patterns, FastAPI is the better fit.
    language: en-US
main entity: Which has better documentation?
  type: Question
  accepted answer: Answer
    text: Flask has more third-party tutorials due to age and popularity. FastAPI generates interactive API documentation automatically (Swagger UI + ReDoc), eliminating manual docs work. For API documentation, FastAPI wins. For general learning resources, Flask has more available due to its 15-year head start.
    language: en-US
main entity: What's the migration path from Flask to FastAPI?
  type: Question
  accepted answer: Answer
    text: There's no direct upgrade path. Migration requires rewriting your application, though logic often transfers cleanly. Many teams run both frameworks simultaneously in a microservices architecture. The effort is ~30-50% rewrite effort, making migration viable for performance-critical applications but not necessary for stable, low-traffic APIs.
    language: en-US

How to Choose Between Flask and FastAPI
type: HowTo
description: FastAPI is a modern async-first framework built for high-performance APIs with automatic documentation, while Flask is a lightweight, synchronous framework prioritizing simplicity and flexibility. FastAPI handles ~3x more requests per second in benchmarks, but Flask has broader ecosystem maturity and community resources.
language: en-US
total time: PT3M
step: Consider: Request Handling Speed
step: Consider: Async/Await Support
step: Consider: Auto-Generated Documentation
step: Consider: Data Validation
step: Consider: Learning Curve
step: Consider: Community Size
step: Consider: Production Maturity
tool: A Versus B Comparison Guide
tip: HowToTip
  text: Choose Flask if you're building simple REST APIs, prefer minimal dependencies, need extensive third-party ecosystem support, or value a gentle learning curve for junior developers. Choose FastAPI if you're building modern, high-performance APIs requiring async operations, automatic API documentation, or type-safe request validation out-of-the-box.

Consider: Request Handling Speed
type: HowToStep
position: 1
text: Request Handling Speed: Flask has ~7,500 req/s, while FastAPI has ~22,000 req/s.

Consider: Async/Await Support
type: HowToStep
position: 2
text: Async/Await Support: Flask has Manual with extensions, while FastAPI has Native built-in.

Consider: Auto-Generated Documentation
type: HowToStep
position: 3
text: Auto-Generated Documentation: Flask has Manual setup required, while FastAPI has Automatic (Swagger UI + ReDoc).

Consider: Data Validation
type: HowToStep
position: 4
text: Data Validation: Flask has Manual or extension-based, while FastAPI has Built-in with Pydantic.

Consider: Learning Curve
type: HowToStep
position: 5
text: Learning Curve: Flask has Minimal (50-100 lines for basic app), while FastAPI has Moderate (100-150 lines).

Consider: Community Size
type: HowToStep
position: 6
text: Community Size: Flask has ~95,000 GitHub stars, while FastAPI has ~80,000 GitHub stars.

Consider: Production Maturity
type: HowToStep
position: 7
text: Production Maturity: Flask has 15+ years (since 2010), while FastAPI has 5+ years (since 2018).

claimreview
type: ClaimReview
is accessible for free: true
conditions of access: Free
claim reviewed: Flask vs FastAPI
review body: FastAPI is a modern async-first framework built for high-performance APIs with automatic documentation, while Flask is a lightweight, synchronous framework prioritizing simplicity and flexibility. FastAPI handles ~3x more requests per second in benchmarks, but Flask has broader ecosystem maturity and community resources.
review rating: Rating
  rating: 5
  worst rating: 1
  best rating: 5
  alternate name: Verified Comparison
author: A Versus B
item reviewed: Flask vs FastAPI

Setup Time to First Running App
type: PropertyValue
value: Flask: 8-12 minutes | FastAPI: N/A

Built-in Request/Response Handling
type: PropertyValue
value: Flask: Yes (Werkzeug-based) | FastAPI: N/A

Average Community Response Time (GitHub Issues)
type: PropertyValue
value: Flask: 24-36 hours | FastAPI: N/A

Throughput (Requests Per Second)
type: PropertyValue
value: Flask: ~2,100 req/s | FastAPI: ~32,000 req/s
value reference: FastAPI

Concurrency Model
type: PropertyValue
value: Flask: Synchronous (WSGI) | FastAPI: N/A

Package Size
type: PropertyValue
value: Flask: ~2.5 MB | FastAPI: ~100 KB
value reference: Flask

Third-Party Extensions
type: PropertyValue
value: Flask: 800+ | FastAPI: N/A

Production Deployments (Estimated)
type: PropertyValue
value: Flask: 2.5M+ | FastAPI: N/A

Throughput (Requests/Second)
type: PropertyValue
value: Flask: 400-600 | FastAPI: 8,000-12,000
value reference: FastAPI

Initial Release Year
type: PropertyValue
value: Flask: 2010 | FastAPI: 2018
value reference: Flask

Learning Curve Difficulty
type: PropertyValue
value: Flask: Easy (1.5/5) | FastAPI: Moderate (3.5/5)
value reference: Flask

Type Hint Support
type: PropertyValue
value: Flask: Optional | FastAPI: Full (enforced)

Requests Per Second (Throughput)
type: PropertyValue
value: Flask: ~7,500 req/s | FastAPI: ~22,000 req/s
value reference: FastAPI

Cold Start Time
type: PropertyValue
value: Flask: ~150ms | FastAPI: 300ms
value reference: Flask

Memory Usage (Baseline)
type: PropertyValue
value: Flask: ~30MB | FastAPI: N/A

Available Packages/Modules
type: PropertyValue
value: Flask: ~150,000+ PyPI packages | FastAPI: N/A

ML/Data Science Library Support
type: PropertyValue
value: Flask: Native: NumPy, Pandas, Scikit-learn, TensorFlow, PyTorch | FastAPI: N/A

GitHub Stars (Popularity Proxy)
type: PropertyValue
value: Flask: ~67,000 stars | FastAPI: N/A

Time to First Hello World
type: PropertyValue
value: Flask: 4 lines | FastAPI: N/A

Deployment Without Extra Server
type: PropertyValue
value: Flask: No - requires WSGI server (Gunicorn, uWSGI) | FastAPI: N/A

Default Dependencies
type: PropertyValue
value: Flask: 1 (werkzeug) | FastAPI: 6 (starlette, pydantic, etc.)
value reference: Flask

Async Support
type: PropertyValue
value: Flask: Requires Flask-APScheduler or manual async setup | FastAPI: Native async/await built-in

Auto Documentation Generation
type: PropertyValue
value: Flask: Manual (requires Flask-RESTX, Flasgger) | FastAPI: Automatic (Swagger UI + ReDoc)

Time to 'Hello World' App
type: PropertyValue
value: Flask: 4-5 lines | FastAPI: 8-10 lines
value reference: Flask

Memory Usage (base)
type: PropertyValue
value: Flask: N/A | FastAPI: ~10MB

Built-in Admin Dashboard
type: PropertyValue
value: Flask: N/A | FastAPI: No, requires build

Async Request Support
type: PropertyValue
value: Flask: N/A | FastAPI: Full native support

Third-party Packages
type: PropertyValue
value: Flask: N/A | FastAPI: 2,000+ packages

Latency (p99 response time)
type: PropertyValue
value: Flask: N/A | FastAPI: 8-12 ms

Production Adoption Rate
type: PropertyValue
value: Flask: N/A | FastAPI: 22% (Stack Overflow 2024)

First Release Year
type: PropertyValue
value: Flask: N/A | FastAPI: 2018

Auto API Documentation
type: PropertyValue
value: Flask: N/A | FastAPI: Native (Swagger UI + ReDoc built-in)

Type Safety Support
type: PropertyValue
value: Flask: N/A | FastAPI: Native (Python type hints)

Framework Requests Per Second
type: PropertyValue
value: Flask: N/A | FastAPI: 10,000

Idle Memory Usage
type: PropertyValue
value: Flask: N/A | FastAPI: 50-80

Built-in Documentation Generation
type: PropertyValue
value: Flask: N/A | FastAPI: Automatic (Swagger UI + ReDoc)

Python/Go Package Ecosystem Size
type: PropertyValue
value: Flask: N/A | FastAPI: 400,000+

Deployment Model
type: PropertyValue
value: Flask: N/A | FastAPI: Requires app server (Uvicorn)

Time to Production (Small API)
type: PropertyValue
value: Flask: N/A | FastAPI: 4-8

Average Latency (Hello World)
type: PropertyValue
value: Flask: N/A | FastAPI: ~85 ms

PyPI Weekly Downloads
type: PropertyValue
value: Flask: N/A | FastAPI: ~2.8M (Jan 2026)

Python Version Support
type: PropertyValue
value: Flask: N/A | FastAPI: 3.7+

Built-in Request Validation
type: PropertyValue
value: Flask: N/A | FastAPI: Yes (Pydantic)

Time to Hello World API
type: PropertyValue
value: Flask: N/A | FastAPI: ~5 minutes

Throughput Performance
type: PropertyValue
value: Flask: N/A | FastAPI: ~15,000 req/s

Memory Usage (Hello World)
type: PropertyValue
value: Flask: N/A | FastAPI: ~40 MB

Throughput Benchmark (requests/sec)
type: PropertyValue
value: Flask: N/A | FastAPI: ~18,000 req/s

Framework Age
type: PropertyValue
value: Flask: N/A | FastAPI: 6 years (2018)

Time to Build Basic CRUD App
type: PropertyValue
value: Flask: N/A | FastAPI: 3.5 hours (manual setup required)

Built-in ORM
type: PropertyValue
value: Flask: N/A | FastAPI: No (requires external library)

Native Async Support
type: PropertyValue
value: Flask: N/A | FastAPI: Native (async/await throughout)

Ecosystem Size (package repositories)
type: PropertyValue
value: Flask: N/A | FastAPI: ~480,000 packages (PyPI)

Weekly npm Downloads
type: PropertyValue
value: Flask: N/A | FastAPI: ~1.2M (PyPI: ~2.8M)

Built-in Dependency Injection
type: PropertyValue
value: Flask: N/A | FastAPI: Manual setup required

Auto-generated API Documentation
type: PropertyValue
value: Flask: N/A | FastAPI: Yes (automatic)

Async-First Support
type: PropertyValue
value: Flask: N/A | FastAPI: Native, default behavior

Core Library Size
type: PropertyValue
value: Flask: N/A | FastAPI: 1,200KB (with uvicorn)

Async Support Quality
type: PropertyValue
value: Flask: N/A | FastAPI: Native async/await with asyncio

Framework Type
type: PropertyValue
value: Flask: N/A | FastAPI: High-level API framework (built on Starlette)

Performance - Request Throughput
type: PropertyValue
value: Flask: N/A | FastAPI: ~15,000-18,000 req/sec

Built-in Validation Framework
type: PropertyValue
value: Flask: N/A | FastAPI: Pydantic (integrated)

Request Throughput
type: PropertyValue
value: Flask: N/A | FastAPI: ~12,000 req/s

Cold Start Latency
type: PropertyValue
value: Flask: N/A | FastAPI: 300ms

Weekly Package Downloads
type: PropertyValue
value: Flask: N/A | FastAPI: ~450,000 (PyPI)

Minimum Python/Node Version
type: PropertyValue
value: Flask: N/A | FastAPI: Python 3.7+

Production Maturity
type: PropertyValue
value: Flask: N/A | FastAPI: 7 years

P99 Latency (typical)
type: PropertyValue
value: Flask: N/A | FastAPI: 150-250

Peak Throughput (Req/s)
type: PropertyValue
value: Flask: N/A | FastAPI: ~10,000 req/s

Memory Usage per Process
type: PropertyValue
value: Flask: N/A | FastAPI: ~40 MB

Community Library Ecosystem
type: PropertyValue
value: Flask: N/A | FastAPI: 500,000+ PyPI packages (Python ecosystem)

Job Market Postings (2026)
type: PropertyValue
value: Flask: N/A | FastAPI: ~12,000 positions

Framework Maturity
type: PropertyValue
value: Flask: N/A | FastAPI: 6 years (released 2018)

Minimum Memory Footprint
type: PropertyValue
value: Flask: N/A | FastAPI: 40MB

GitHub Stars (as of 2026)
type: PropertyValue
value: Flask: N/A | FastAPI: 68,000+ stars

NPM Weekly Downloads
type: PropertyValue
value: Flask: N/A | FastAPI: 2.5M weekly

Time to Production Hello World
type: PropertyValue
value: Flask: N/A | FastAPI: 5 minutes

Built-in Features Count
type: PropertyValue
value: Flask: N/A | FastAPI: 12 core features

Production Applications (market estimate)
type: PropertyValue
value: Flask: N/A | FastAPI: 45,000+ apps

Active Job Listings (2025)
type: PropertyValue
value: Flask: N/A | FastAPI: 42,000

Learning Curve
type: PropertyValue
value: Flask: N/A | FastAPI: 30-40 hours

Memory Usage (Idle Instance)
type: PropertyValue
value: Flask: N/A | FastAPI: ~80-120 MB

Built-in API Documentation
type: PropertyValue
value: Flask: N/A | FastAPI: Yes (Swagger UI + ReDoc automatic)

Native Type Validation
type: PropertyValue
value: Flask: N/A | FastAPI: Yes (Pydantic built-in)

Requests Per Second (Single Instance)
type: PropertyValue
value: Flask: N/A | FastAPI: ~7,500 req/s

Memory Footprint Per Process
type: PropertyValue
value: Flask: N/A | FastAPI: ~15 MB

Time to Basic API (Hello World)
type: PropertyValue
value: Flask: N/A | FastAPI: ~5 lines

Built-in Authentication
type: PropertyValue
value: Flask: N/A | FastAPI: No (requires FastAPI-Users, python-jose)

Database ORM Included
type: PropertyValue
value: Flask: N/A | FastAPI: No (requires SQLAlchemy, Tortoise-ORM)

Ecosystem Size (Packages)
type: PropertyValue
value: Flask: N/A | FastAPI: ~350,000 PyPI packages (FastAPI-specific: ~4,000)

Application Startup Time
type: PropertyValue
value: Flask: N/A | FastAPI: 150ms (average)

Requests Per Second (1KB payload)
type: PropertyValue
value: Flask: N/A | FastAPI: ~28,000

Available Packages/Libraries
type: PropertyValue
value: Flask: N/A | FastAPI: ~500,000 (PyPI)

Auto-Generated API Docs
type: PropertyValue
value: Flask: N/A | FastAPI: Yes (Swagger/ReDoc)

NPM/PyPI Weekly Downloads
type: PropertyValue
value: Flask: N/A | FastAPI: ~2.8M (PyPI/month)

Lines of Code for Basic Endpoint
type: PropertyValue
value: Flask: N/A | FastAPI: 5-8 lines

GitHub Stars (2026)
type: PropertyValue
value: Flask: N/A | FastAPI: 75,000+

Production Readiness Without External Server
type: PropertyValue
value: Flask: N/A | FastAPI: Requires ASGI (Uvicorn)

SpeakableSpecification
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Flask — Wikipedia
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FastAPI — Wikipedia
type: CreativeWork

Compare Flask vs FastAPI
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object: Flask
object: FastAPI

Type Hint Support
type: PropertyValue
value reference: Developer Experience

Requests Per Second (Throughput)
type: PropertyValue
value reference: Performance

Cold Start Time
type: PropertyValue
value reference: Performance

Memory Usage (Baseline)
type: PropertyValue
value reference: Performance

Available Packages/Modules
type: PropertyValue
value reference: Ecosystem

ML/Data Science Library Support
type: PropertyValue
value reference: Ecosystem

GitHub Stars (Popularity Proxy)
type: PropertyValue
value reference: Community

Time to First Hello World
type: PropertyValue
value reference: Ease of Use

Deployment Without Extra Server
type: PropertyValue
value reference: DevOps

Default Dependencies
type: PropertyValue
value reference: Installation

Async Support
type: PropertyValue
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Auto Documentation Generation
type: PropertyValue
value reference: Developer Experience

Time to 'Hello World' App
type: PropertyValue
value reference: Developer Experience

Memory Usage (base)
type: PropertyValue
value reference: Performance

Built-in Admin Dashboard
type: PropertyValue
value reference: Features

Async Request Support
type: PropertyValue
value reference: Features

Third-party Packages
type: PropertyValue
value reference: Ecosystem

Latency (p99 response time)
type: PropertyValue
value reference: Performance

Production Adoption Rate
type: PropertyValue
value reference: Industry Use

First Release Year
type: PropertyValue
value reference: History

Auto API Documentation
type: PropertyValue
value reference: Features

Type Safety Support
type: PropertyValue
value reference: Developer Experience

Framework Requests Per Second
type: PropertyValue
value reference: Performance

Idle Memory Usage
type: PropertyValue
value reference: Resource Efficiency

Built-in Documentation Generation
type: PropertyValue
value reference: Developer Experience

Python/Go Package Ecosystem Size
type: PropertyValue
value reference: Ecosystem

Deployment Model
type: PropertyValue
value reference: Architecture

Time to Production (Small API)
type: PropertyValue
value reference: Development

Average Latency (Hello World)
type: PropertyValue
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PyPI Weekly Downloads
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Python Version Support
type: PropertyValue
value reference: Compatibility

Built-in Request Validation
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Time to Hello World API
type: PropertyValue
value reference: Developer Experience

Throughput Performance
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Memory Usage (Hello World)
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Throughput Benchmark (requests/sec)
type: PropertyValue
value reference: Performance

Framework Age
type: PropertyValue
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Time to Build Basic CRUD App
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Built-in ORM
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Native Async Support
type: PropertyValue
value reference: Architecture

Ecosystem Size (package repositories)
type: PropertyValue
value reference: Ecosystem

Weekly npm Downloads
type: PropertyValue
value reference: Popularity

Built-in Dependency Injection
type: PropertyValue
value reference: Architecture

Auto-generated API Documentation
type: PropertyValue
value reference: Features

Async-First Support
type: PropertyValue
value reference: Language Design

Core Library Size
type: PropertyValue
value reference: Footprint

Async Support Quality
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Framework Type
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Performance - Request Throughput
type: PropertyValue
value reference: Performance

Built-in Validation Framework
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value reference: Developer Experience

Request Throughput
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Cold Start Latency
type: PropertyValue
value reference: Performance

Weekly Package Downloads
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value reference: Popularity

Minimum Python/Node Version
type: PropertyValue
value reference: Requirements

Production Maturity
type: PropertyValue
value reference: Enterprise

P99 Latency (typical)
type: PropertyValue
value reference: Performance

Peak Throughput (Req/s)
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Memory Usage per Process
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Community Library Ecosystem
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Job Market Postings (2026)
type: PropertyValue
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Framework Maturity
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Minimum Memory Footprint
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GitHub Stars (as of 2026)
type: PropertyValue
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NPM Weekly Downloads
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Time to Production Hello World
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Built-in Features Count
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Production Applications (market estimate)
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Active Job Listings (2025)
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Learning Curve
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Memory Usage (Idle Instance)
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Built-in API Documentation
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Native Type Validation
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Requests Per Second (Single Instance)
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Memory Footprint Per Process
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Time to Basic API (Hello World)
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Built-in Authentication
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Database ORM Included
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Ecosystem Size (Packages)
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Application Startup Time
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Requests Per Second (1KB payload)
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Available Packages/Libraries
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Auto-Generated API Docs
type: PropertyValue
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NPM/PyPI Weekly Downloads
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Lines of Code for Basic Endpoint
type: PropertyValue
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GitHub Stars (2026)
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Production Readiness Without External Server
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value reference: Deployment