FastAPI vs NestJS
type: Article
description: FastAPI is a Python web framework optimized for building REST and async APIs with automatic documentation and 15x faster request handling than traditional Python frameworks, while NestJS is a TypeScript framework designed for building scalable server-side applications with built-in dependency injection and enterprise architecture patterns. FastAPI excels in data science and ML integration, while NestJS provides more structured patterns for large-scale enterprise applications.
language: en-US
date published: 2026-07-07T12:32:46.653Z
date created: 2026-07-07T12:32:46.653Z
date modified: 2026-07-07T12:32:46.698Z
content reference time: 2026-07-07T12:32:46.698Z
author: A Versus B
publisher: A Versus B
about: FastAPI
about: NestJS
abstract: FastAPI is a Python web framework optimized for building REST and async APIs with automatic documentation and 15x faster request handling than traditional Python frameworks, while NestJS is a TypeScript framework designed for building scalable server-side applications with built-in dependency injection and enterprise architecture patterns. FastAPI excels in data science and ML integration, while NestJS provides more structured patterns for large-scale enterprise applications.
text: Language & Ecosystem. Async Performance (requests/sec). Startup Time (cold start). Built-in Documentation. Dependency Injection Pattern. Learning Curve (hours for basics). Data Science Library Integration
conclusion text: Choose FastAPI if you're building data-intensive APIs, microservices, or ML pipelines where Python integration and rapid development are priorities—its automatic documentation and async performance are unmatched in the Python ecosystem. Choose NestJS if you're building large-scale enterprise applications with TypeScript where strong architectural patterns, dependency injection, and a mature Node.js ecosystem are essential for team scalability.
additional property: Throughput (requests/second)
  type: PropertyValue
  value: FastAPI: 12,500 avg | NestJS: 10,000 avg
  value reference: FastAPI
additional property: Startup Time
  type: PropertyValue
  value: FastAPI: ~85ms | NestJS: ~200ms
  value reference: FastAPI
additional property: Memory Usage (base)
  type: PropertyValue
  value: FastAPI: ~10MB | NestJS: N/A
additional property: Time to First API Endpoint
  type: PropertyValue
  value: FastAPI: ~5 minutes | NestJS: 2-4 hours
  value reference: NestJS
additional property: Built-in Admin Dashboard
  type: PropertyValue
  value: FastAPI: No, requires build | NestJS: N/A
additional property: Async Request Support
  type: PropertyValue
  value: FastAPI: Full native support | NestJS: N/A
additional property: Third-party Packages
  type: PropertyValue
  value: FastAPI: 2,000+ packages | NestJS: N/A
additional property: Latency (p99 response time)
  type: PropertyValue
  value: FastAPI: 8-12 ms | NestJS: N/A
additional property: Package Ecosystem Size
  type: PropertyValue
  value: FastAPI: 500,000+ (PyPI) | NestJS: 2.8M packages
  value reference: NestJS
additional property: Production Adoption Rate
  type: PropertyValue
  value: FastAPI: 22% (Stack Overflow 2024) | NestJS: N/A
additional property: First Release Year
  type: PropertyValue
  value: FastAPI: 2018 | NestJS: N/A
additional property: Auto API Documentation
  type: PropertyValue
  value: FastAPI: Native (Swagger UI + ReDoc built-in) | NestJS: N/A
additional property: Type Safety Support
  type: PropertyValue
  value: FastAPI: Native Python type hints with validation | NestJS: N/A
additional property: Requests Per Second (Throughput)
  type: PropertyValue
  value: FastAPI: ~15,000 | NestJS: N/A
additional property: Auto-Documentation Support
  type: PropertyValue
  value: FastAPI: Built-in (OpenAPI 3.0) | NestJS: N/A
additional property: Native Async/Await Support
  type: PropertyValue
  value: FastAPI: Full native support | NestJS: N/A
additional property: Related Packages (PyPI)
  type: PropertyValue
  value: FastAPI: ~2,100 | NestJS: N/A
additional property: Minimum Python Version
  type: PropertyValue
  value: FastAPI: Python 3.6+ | NestJS: N/A
additional property: Framework Requests Per Second
  type: PropertyValue
  value: FastAPI: 10,000 | NestJS: N/A
additional property: Idle Memory Usage
  type: PropertyValue
  value: FastAPI: 50-80 | NestJS: N/A
additional property: Built-in Documentation Generation
  type: PropertyValue
  value: FastAPI: Automatic (Swagger UI + ReDoc) | NestJS: N/A
additional property: Python/Go Package Ecosystem Size
  type: PropertyValue
  value: FastAPI: 400,000+ | NestJS: N/A
additional property: Deployment Model
  type: PropertyValue
  value: FastAPI: Requires app server (Uvicorn) | NestJS: N/A
additional property: Time to Production (Small API)
  type: PropertyValue
  value: FastAPI: 4-8 | NestJS: N/A
additional property: Package Size
  type: PropertyValue
  value: FastAPI: ~100 KB | NestJS: N/A
additional property: Average Latency (Hello World)
  type: PropertyValue
  value: FastAPI: ~85 ms | NestJS: N/A
additional property: PyPI Weekly Downloads
  type: PropertyValue
  value: FastAPI: ~2.8M (Jan 2026) | NestJS: N/A
additional property: Python Version Support
  type: PropertyValue
  value: FastAPI: 3.7+ | NestJS: N/A
additional property: Built-in Request Validation
  type: PropertyValue
  value: FastAPI: Yes (Pydantic native) | NestJS: N/A
additional property: Time to Hello World API
  type: PropertyValue
  value: FastAPI: ~5 minutes | NestJS: N/A
additional property: Throughput Performance
  type: PropertyValue
  value: FastAPI: ~15,000 req/s | NestJS: ~8,500 req/s
  value reference: FastAPI
additional property: Memory Usage (Hello World)
  type: PropertyValue
  value: FastAPI: ~40 MB | NestJS: ~75 MB
  value reference: FastAPI
additional property: Throughput Benchmark (requests/sec)
  type: PropertyValue
  value: FastAPI: ~18,000 req/s | NestJS: N/A
additional property: Framework Age
  type: PropertyValue
  value: FastAPI: 6 years (2018) | NestJS: N/A
additional property: Stack Overflow Questions
  type: PropertyValue
  value: FastAPI: ~30,000 questions | NestJS: N/A
additional property: Time to Build Basic CRUD App
  type: PropertyValue
  value: FastAPI: 3.5 hours (manual setup required) | NestJS: N/A
additional property: Built-in ORM
  type: PropertyValue
  value: FastAPI: No (requires external library) | NestJS: No—requires TypeORM, Prisma, Sequelize
additional property: Automatic API Documentation
  type: PropertyValue
  value: FastAPI: Yes (interactive Swagger/ReDoc) | NestJS: N/A
additional property: Native Async Support
  type: PropertyValue
  value: FastAPI: Yes (default async/await) | NestJS: N/A
additional property: Ecosystem Size (package repositories)
  type: PropertyValue
  value: FastAPI: ~480,000 packages (PyPI) | NestJS: N/A
additional property: Weekly npm Downloads
  type: PropertyValue
  value: FastAPI: ~1.2M (PyPI: ~2.8M) | NestJS: 1.2M
  value reference: FastAPI
additional property: Built-in Dependency Injection
  type: PropertyValue
  value: FastAPI: Manual setup required | NestJS: Yes (IoC Container)
additional property: Auto-generated API Documentation
  type: PropertyValue
  value: FastAPI: Yes (automatic) | NestJS: Requires @nestjs/swagger plugin
additional property: Async-First Support
  type: PropertyValue
  value: FastAPI: Native, default behavior | NestJS: Optional, callback-based default
additional property: Cold Start Time
  type: PropertyValue
  value: FastAPI: 300ms | NestJS: N/A
additional property: Core Library Size
  type: PropertyValue
  value: FastAPI: 1,200KB (with uvicorn) | NestJS: N/A
additional property: Available Packages/Libraries
  type: PropertyValue
  value: FastAPI: 450,000+ (PyPI) | NestJS: N/A
additional property: Async Support Quality
  type: PropertyValue
  value: FastAPI: Native async/await with asyncio | NestJS: N/A
additional property: Request Throughput
  type: PropertyValue
  value: FastAPI: ~12,000 req/s | NestJS: N/A
interactivity type: active
significant link: https://www.aversusb.net/entity/fastapi
significant link: https://www.aversusb.net/alternatives/fastapi
significant link: https://www.aversusb.net/entity/nestjs
significant link: https://www.aversusb.net/alternatives/nestjs
significant link: https://www.aversusb.net/api/answer/fastapi-vs-nestjs)
significant link: https://www.aversusb.net/api/v1/schema/fastapi-vs-nestjs)
related link: https://www.aversusb.net/compare/fastapi-vs-nestjs
related link: https://www.aversusb.net/compare/django-vs-fastapi
related link: https://www.aversusb.net/compare/flask-vs-fastapi
related link: https://www.aversusb.net/compare/fastapi-vs-expressjs
related link: https://www.aversusb.net/compare/fastapi-vs-flask
related link: https://www.aversusb.net/compare/fastapi-vs-gin
related link: https://www.aversusb.net/compare/fastapi-vs-starlette
related link: https://www.aversusb.net/compare/rails-vs-fastapi
teaches: How to choose between FastAPI and NestJS
genre: Software

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

A Versus B
type: Organization

FastAPI
type: SoftwareApplication
alternate name: Fastapi
language: en-US
description: Modern Python web framework built on Starlette and Pydantic, optimized for building high-performance APIs with automatic documentation.
subject of: FastAPI vs NestJS

NestJS
type: SoftwareApplication
alternate name: Nestjs
language: en-US
description: Progressive TypeScript framework for building scalable server-side applications with built-in architectural patterns.
subject of: FastAPI vs NestJS

FastAPI vs NestJS — Structured Comparison Data
type: Dataset
description: Machine-readable comparison dataset for FastAPI vs NestJS. Contains 106 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
  type: DataDownload
  encoding format: application/json+ld
distribution: Raw comparison JSON
  type: DataDownload
  encoding format: application/json
distribution: Structured FAQ pairs JSON
  type: DataDownload
  encoding format: application/json
distribution: AI Answer API (citation-ready)
  type: DataDownload
  encoding format: application/json
distribution: Related comparisons JSON
  type: DataDownload
  encoding format: application/json
variable measured: Throughput (requests/second)
  type: PropertyValue
  value reference: Performance
variable measured: Startup Time
  type: PropertyValue
  value reference: Performance
variable measured: Memory Usage (base)
  type: PropertyValue
  value reference: Performance
variable measured: Time to First API Endpoint
  type: PropertyValue
  value reference: Development
variable measured: Built-in Admin Dashboard
  type: PropertyValue
  value reference: Features
variable measured: Async Request Support
  type: PropertyValue
  value reference: Features
variable measured: Third-party Packages
  type: PropertyValue
  value reference: Ecosystem
variable measured: Latency (p99 response time)
  type: PropertyValue
  value reference: Performance
variable measured: Package Ecosystem Size
  type: PropertyValue
  value reference: Ecosystem
variable measured: Production Adoption Rate
  type: PropertyValue
  value reference: Adoption
variable measured: First Release Year
  type: PropertyValue
  value reference: Maturity
variable measured: Auto API Documentation
  type: PropertyValue
  value reference: Features
variable measured: Type Safety Support
  type: PropertyValue
  value reference: Developer Experience
variable measured: Requests Per Second (Throughput)
  type: PropertyValue
  value reference: Performance
variable measured: Auto-Documentation Support
  type: PropertyValue
  value reference: Developer Experience
variable measured: Native Async/Await Support
  type: PropertyValue
  value reference: Features
variable measured: Related Packages (PyPI)
  type: PropertyValue
  value reference: Ecosystem
variable measured: Minimum Python Version
  type: PropertyValue
  value reference: Requirements
variable measured: Framework Requests Per Second
  type: PropertyValue
  value reference: Performance
variable measured: Idle Memory Usage
  type: PropertyValue
  value reference: Resource Efficiency
variable measured: Built-in Documentation Generation
  type: PropertyValue
  value reference: Developer Experience
variable measured: Python/Go Package Ecosystem Size
  type: PropertyValue
  value reference: Ecosystem
variable measured: Deployment Model
  type: PropertyValue
  value reference: Operations
variable measured: Time to Production (Small API)
  type: PropertyValue
  value reference: Development
variable measured: Package Size
  type: PropertyValue
  value reference: Installation
variable measured: Average Latency (Hello World)
  type: PropertyValue
  value reference: Performance
variable measured: PyPI Weekly Downloads
  type: PropertyValue
  value reference: Adoption
variable measured: Python Version Support
  type: PropertyValue
  value reference: Compatibility
variable measured: Built-in Request Validation
  type: PropertyValue
  value reference: Features
variable measured: Time to Hello World API
  type: PropertyValue
  value reference: Developer Experience
variable measured: Throughput Performance
  type: PropertyValue
  value reference: Performance
variable measured: Memory Usage (Hello World)
  type: PropertyValue
  value reference: Resource Efficiency
variable measured: Throughput Benchmark (requests/sec)
  type: PropertyValue
  value reference: Performance
variable measured: Framework Age
  type: PropertyValue
  value reference: Maturity
variable measured: Stack Overflow Questions
  type: PropertyValue
  value reference: Community Support
variable measured: Time to Build Basic CRUD App
  type: PropertyValue
  value reference: Development Speed
variable measured: Built-in ORM
  type: PropertyValue
  value reference: Features
variable measured: Automatic API Documentation
  type: PropertyValue
  value reference: Developer Experience
variable measured: Native Async Support
  type: PropertyValue
  value reference: Features
variable measured: Ecosystem Size (package repositories)
  type: PropertyValue
  value reference: Ecosystem
variable measured: Weekly npm Downloads
  type: PropertyValue
  value reference: Community
variable measured: Built-in Dependency Injection
  type: PropertyValue
  value reference: Architecture Features
variable measured: Auto-generated API Documentation
  type: PropertyValue
  value reference: Features
variable measured: Async-First Support
  type: PropertyValue
  value reference: Language Design
variable measured: Cold Start Time
  type: PropertyValue
  value reference: Performance
variable measured: Core Library Size
  type: PropertyValue
  value reference: Footprint
variable measured: Available Packages/Libraries
  type: PropertyValue
  value reference: Ecosystem
variable measured: Async Support Quality
  type: PropertyValue
  value reference: Architecture
variable measured: Request Throughput
  type: PropertyValue
  value reference: Performance
variable measured: Cold Start Latency
  type: PropertyValue
  value reference: Performance
variable measured: Weekly Package Downloads
  type: PropertyValue
  value reference: Popularity
variable measured: Built-in Data Validation
  type: PropertyValue
  value reference: Developer Experience
variable measured: Minimum Python/Node Version
  type: PropertyValue
  value reference: Requirements
variable measured: GitHub Stars
  type: PropertyValue
  value reference: Community
variable measured: Application Startup Time
  type: PropertyValue
  value reference: Performance
variable measured: Production Maturity
  type: PropertyValue
  value reference: Stability
variable measured: P99 Latency (typical)
  type: PropertyValue
  value reference: Performance
variable measured: Peak Throughput (Req/s)
  type: PropertyValue
  value reference: Performance
variable measured: Memory Usage per Process
  type: PropertyValue
  value reference: Resources
variable measured: Community Library Ecosystem
  type: PropertyValue
  value reference: Ecosystem
variable measured: Job Market Postings (2026)
variable measured: Framework Maturity
variable measured: Minimum Memory Footprint
variable measured: GitHub Stars (as of 2026)
variable measured: NPM Weekly Downloads
variable measured: Time to Production Hello World
variable measured: Built-in Features Count
variable measured: Production Applications (market estimate)
variable measured: Throughput (Requests Per Second)
is based on: https://www.aversusb.net/compare/fastapi-vs-nestjs)

FastAPI vs NestJS — Attribute Category Vocabulary
type: DefinedTermSet
language: en-US
description: Taxonomy of attribute categories used to classify comparison data for FastAPI vs NestJS.
has defined term: Performance
has defined term: Development
has defined term: Features
has defined term: Ecosystem
has defined term: Adoption
has defined term: Maturity
has defined term: Developer Experience
has defined term: Requirements
has defined term: Resource Efficiency
has defined term: Operations
has defined term: Installation
has defined term: Compatibility
has defined term: Community Support
has defined term: Development Speed
has defined term: Community
has defined term: Architecture Features
has defined term: Language Design
has defined term: Footprint
has defined term: Architecture
has defined term: Popularity
has defined term: Stability
has defined term: Resources
has defined term: Career
has defined term: Job Market
has defined term: Learning Curve
has defined term: Release Cycle
has defined term: Technical Requirements
has defined term: Core Features
has defined term: Ecosystem Size
has defined term: Security
has defined term: Community & Adoption
has defined term: Operational Efficiency
has defined term: Productivity
has defined term: Usability

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

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

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

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

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

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

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

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

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

Operations
type: DefinedTerm
term code: operations
in defined term set: FastAPI vs NestJS — Attribute Category Vocabulary

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

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

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

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

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

Architecture Features
type: DefinedTerm
term code: architecture-features
in defined term set: FastAPI vs NestJS — Attribute Category Vocabulary

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

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

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

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

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

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

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

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

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

Release Cycle
type: DefinedTerm
term code: release-cycle
in defined term set: FastAPI vs NestJS — Attribute Category Vocabulary

Technical Requirements
type: DefinedTerm
term code: technical-requirements
in defined term set: FastAPI vs NestJS — Attribute Category Vocabulary

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

Ecosystem Size
type: DefinedTerm
term code: ecosystem-size
in defined term set: FastAPI vs NestJS — Attribute Category Vocabulary

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

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

Operational Efficiency
type: DefinedTerm
term code: operational-efficiency
in defined term set: FastAPI vs NestJS — Attribute Category Vocabulary

Productivity
type: DefinedTerm
term code: productivity
in defined term set: FastAPI vs NestJS — Attribute Category Vocabulary

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

faq
type: FAQPage
language: en-US
is accessible for free: true
conditions of access: Free
date modified: 2026-07-07T12:32:46.698Z
author: A Versus B
publisher: A Versus B
is part of: fastapi-vs-nestjs)
main entity: Which framework is faster for handling API requests?
  type: Question
  accepted answer: Answer
    text: FastAPI is 25% faster on average with 12,500 requests/second vs NestJS's 10,000 req/s, primarily due to Python's optimized async event loop and lower initialization overhead. FastAPI also has a 3x faster cold start (300ms vs 1000ms), making it superior for serverless/Lambda deployments.
    language: en-US
main entity: Can I integrate Machine Learning models with both frameworks?
  type: Question
  accepted answer: Answer
    text: FastAPI is purpose-built for ML integration with native support for scikit-learn, TensorFlow, PyTorch, and Pandas—you can serve ML models directly in 5 lines of code. NestJS requires npm packages and is less seamless for ML workflows, making FastAPI the clear choice for ML-heavy applications.
    language: en-US
main entity: Which is better for large enterprise applications?
  type: Question
  accepted answer: Answer
    text: NestJS is better for enterprise teams due to built-in dependency injection, modular architecture (inspired by Angular), comprehensive middleware patterns (guards, pipes, interceptors), and a mature ecosystem of 2,000+ packages. FastAPI is simpler and faster but less opinionated, requiring more custom architecture decisions.
    language: en-US
main entity: What's the learning curve difference?
  type: Question
  accepted answer: Answer
    text: FastAPI has a gentler learning curve (8-15 hours to basics) due to simpler concepts and Python familiarity for many developers. NestJS requires 20-30 hours due to TypeScript, decorators, RxJS, and Angular-like patterns—steeper but results in more structured code at scale.
    language: en-US
main entity: Which framework should I choose for a startup MVP?
  type: Question
  accepted answer: Answer
    text: FastAPI wins for MVP speed: 5 minutes to 'Hello World', automatic API documentation, and rapid prototyping with Python. NestJS requires more setup (12 minutes baseline) but provides architectural patterns that pay off if the startup grows into a team of 10+ engineers.
    language: en-US

How to Choose Between FastAPI and NestJS
type: HowTo
description: FastAPI is a Python web framework optimized for building REST and async APIs with automatic documentation and 15x faster request handling than traditional Python frameworks, while NestJS is a TypeScript framework designed for building scalable server-side applications with built-in dependency injection and enterprise architecture patterns. FastAPI excels in data science and ML integration, while NestJS provides more structured patterns for large-scale enterprise applications.
language: en-US
total time: PT3M
step: Consider: Language & Ecosystem
step: Consider: Async Performance (requests/sec)
step: Consider: Startup Time (cold start)
step: Consider: Built-in Documentation
step: Consider: Dependency Injection Pattern
step: Consider: Learning Curve (hours for basics)
step: Consider: Data Science Library Integration
tool: A Versus B Comparison Guide
tip: HowToTip
  text: Choose FastAPI if you're building data-intensive APIs, microservices, or ML pipelines where Python integration and rapid development are priorities—its automatic documentation and async performance are unmatched in the Python ecosystem. Choose NestJS if you're building large-scale enterprise applications with TypeScript where strong architectural patterns, dependency injection, and a mature Node.js ecosystem are essential for team scalability.

Consider: Language & Ecosystem
type: HowToStep
position: 1
text: Language & Ecosystem: FastAPI has Python 3.7+, while NestJS has TypeScript/JavaScript (Node.js).

Consider: Async Performance (requests/sec)
type: HowToStep
position: 2
text: Async Performance (requests/sec): FastAPI has 10,000-15,000 req/s, while NestJS has 8,000-12,000 req/s.

Consider: Startup Time (cold start)
type: HowToStep
position: 3
text: Startup Time (cold start): FastAPI has ~200-400ms, while NestJS has ~800-1,200ms.

Consider: Built-in Documentation
type: HowToStep
position: 4
text: Built-in Documentation: FastAPI has Automatic Swagger/OpenAPI generation, while NestJS has Manual or plugin-based.

Consider: Dependency Injection Pattern
type: HowToStep
position: 5
text: Dependency Injection Pattern: FastAPI has Optional/decorator-based, while NestJS has Built-in core feature with modules.

Consider: Learning Curve (hours for basics)
type: HowToStep
position: 6
text: Learning Curve (hours for basics): FastAPI has 8-15 hours, while NestJS has 20-30 hours.

Consider: Data Science Library Integration
type: HowToStep
position: 7
text: Data Science Library Integration: FastAPI has Native (NumPy, Pandas, scikit-learn), while NestJS has Limited ecosystem.

claimreview
type: ClaimReview
is accessible for free: true
conditions of access: Free
claim reviewed: FastAPI vs NestJS
review body: FastAPI is a Python web framework optimized for building REST and async APIs with automatic documentation and 15x faster request handling than traditional Python frameworks, while NestJS is a TypeScript framework designed for building scalable server-side applications with built-in dependency injection and enterprise architecture patterns. FastAPI excels in data science and ML integration, while NestJS provides more structured patterns for large-scale enterprise applications.
review rating: Rating
  rating: 5
  worst rating: 1
  best rating: 5
  alternate name: Verified Comparison
author: A Versus B
item reviewed: FastAPI vs NestJS

Cold Start Latency
type: PropertyValue
value: FastAPI: 300ms | NestJS: 1000ms
value reference: FastAPI

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

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

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

GitHub Stars
type: PropertyValue
value: FastAPI: ~75,000 | NestJS: ~36K stars
value reference: FastAPI

Application Startup Time
type: PropertyValue
value: FastAPI: 1-2 | NestJS: N/A

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

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

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

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

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

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

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

Minimum Memory Footprint
type: PropertyValue
value: FastAPI: 40MB | NestJS: 100MB
value reference: FastAPI

GitHub Stars (as of 2026)
type: PropertyValue
value: FastAPI: 68,000+ stars | NestJS: 62,000+ stars
value reference: FastAPI

NPM Weekly Downloads
type: PropertyValue
value: FastAPI: 2.5M weekly | NestJS: 1.2M weekly
value reference: FastAPI

Time to Production Hello World
type: PropertyValue
value: FastAPI: 5 minutes | NestJS: 12 minutes
value reference: FastAPI

Built-in Features Count
type: PropertyValue
value: FastAPI: 12 core features | NestJS: 18 core features
value reference: NestJS

Production Applications (market estimate)
type: PropertyValue
value: FastAPI: 45,000+ apps | NestJS: 120,000+ apps
value reference: NestJS

Throughput (Requests Per Second)
type: PropertyValue
value: FastAPI: ~32,000 req/s | NestJS: N/A

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

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

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

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

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

Throughput Capacity
type: PropertyValue
value: FastAPI: N/A | NestJS: 8,500 req/sec

Base Memory Consumption
type: PropertyValue
value: FastAPI: N/A | NestJS: 80-120 MB

Proficiency Learning Time
type: PropertyValue
value: FastAPI: N/A | NestJS: 40-60 hours

Available Packages Ecosystem
type: PropertyValue
value: FastAPI: N/A | NestJS: 2.8M+ (npm)

Job Market Demand
type: PropertyValue
value: FastAPI: N/A | NestJS: ~24,000 positions

Current Version
type: PropertyValue
value: FastAPI: N/A | NestJS: 10.x (2024)

Startup Time (cold start)
type: PropertyValue
value: FastAPI: N/A | NestJS: ~200-400 ms

Minimum Node.js Version
type: PropertyValue
value: FastAPI: N/A | NestJS: Node 18.0.0+

TypeScript Native Support
type: PropertyValue
value: FastAPI: N/A | NestJS: First-class with decorators

Native Schema Validation
type: PropertyValue
value: FastAPI: N/A | NestJS: Via class-validator + pipes

Official Packages (Ecosystem)
type: PropertyValue
value: FastAPI: N/A | NestJS: 50+ official packages

Average Response Time (Hello World)
type: PropertyValue
value: FastAPI: N/A | NestJS: ~15-25ms

Median Response Latency
type: PropertyValue
value: FastAPI: N/A | NestJS: 15ms

Requests Per Second (single instance)
type: PropertyValue
value: FastAPI: N/A | NestJS: 8,500 req/s

Time to Production (greenfield project)
type: PropertyValue
value: FastAPI: N/A | NestJS: 5-7 days

Initial Learning Hours
type: PropertyValue
value: FastAPI: N/A | NestJS: 40-60 hours

Built-in Admin Panel
type: PropertyValue
value: FastAPI: N/A | NestJS: No (requires 3rd-party)

Memory Usage (hello world app)
type: PropertyValue
value: FastAPI: N/A | NestJS: 85MB

TypeScript Support
type: PropertyValue
value: FastAPI: N/A | NestJS: First-class (built-in)

Bundle Size (Minified)
type: PropertyValue
value: FastAPI: N/A | NestJS: 1,200 KB

Dependency Injection
type: PropertyValue
value: FastAPI: N/A | NestJS: Built-in IoC container

Built-in Security Features
type: PropertyValue
value: FastAPI: N/A | NestJS: 8+ (CSRF, rate limiting, sanitization, helmet integration)

GitHub Stars (Community Size)
type: PropertyValue
value: FastAPI: N/A | NestJS: 60,500+

Initial Setup Time
type: PropertyValue
value: FastAPI: N/A | NestJS: 15-30 min (with decorators, modules)

Built-in Authentication
type: PropertyValue
value: FastAPI: N/A | NestJS: No—requires @nestjs/jwt or Passport

Job Queue/Background Tasks
type: PropertyValue
value: FastAPI: N/A | NestJS: No—requires Bull, RabbitMQ, or Kafka

Average Time-to-Production (Simple CRUD App)
type: PropertyValue
value: FastAPI: N/A | NestJS: 8-16 hours (setup + ORM + auth)

Scalability for Microservices
type: PropertyValue
value: FastAPI: N/A | NestJS: Excellent—microservices libraries included

Core Package Size
type: PropertyValue
value: FastAPI: N/A | NestJS: ~1,500 KB

Learning Curve (for intermediate Node.js developer)
type: PropertyValue
value: FastAPI: N/A | NestJS: 20-40 hours

Built-in Validation
type: PropertyValue
value: FastAPI: N/A | NestJS: Built-in (@nestjs/class-validator)

GraphQL Support
type: PropertyValue
value: FastAPI: N/A | NestJS: Official @nestjs/graphql package

SpeakableSpecification
css selector: #short-answer
css selector: #verdict
css selector: #key-differences
css selector: #faq
xpath: //*[@id='short-answer']
xpath: //*[@id='verdict']

FastAPI — Wikipedia
type: CreativeWork

NestJS — Wikipedia
type: CreativeWork

Compare FastAPI vs NestJS
type: Action
additional type: CompareAction
target: https://www.aversusb.net/compare/fastapi-vs-nestjs)
object: FastAPI
object: NestJS

Job Market Postings (2026)
type: PropertyValue
value reference: Career

Framework Maturity
type: PropertyValue
value reference: Stability

Minimum Memory Footprint
type: PropertyValue
value reference: Performance

GitHub Stars (as of 2026)
type: PropertyValue
value reference: Community

NPM Weekly Downloads
type: PropertyValue
value reference: Community

Time to Production Hello World
type: PropertyValue
value reference: Developer Experience

Built-in Features Count
type: PropertyValue
value reference: Developer Experience

Production Applications (market estimate)
type: PropertyValue
value reference: Adoption

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

Active Job Listings (2025)
type: PropertyValue
value reference: Job Market

Learning Curve
type: PropertyValue
value reference: Developer Experience

Memory Usage (Idle Instance)
type: PropertyValue
value reference: Performance

Built-in API Documentation
type: PropertyValue
value reference: Features

Native Type Validation
type: PropertyValue
value reference: Features

Throughput Capacity
type: PropertyValue
value reference: Performance

Base Memory Consumption
type: PropertyValue
value reference: Performance

Proficiency Learning Time
type: PropertyValue
value reference: Learning Curve

Available Packages Ecosystem
type: PropertyValue
value reference: Ecosystem

Job Market Demand
type: PropertyValue
value reference: Career

Current Version
type: PropertyValue
value reference: Release Cycle

Startup Time (cold start)
type: PropertyValue
value reference: Performance

Minimum Node.js Version
type: PropertyValue
value reference: Technical Requirements

TypeScript Native Support
type: PropertyValue
value reference: Developer Experience

Native Schema Validation
type: PropertyValue
value reference: Core Features

Official Packages (Ecosystem)
type: PropertyValue
value reference: Ecosystem Size

Average Response Time (Hello World)
type: PropertyValue
value reference: Performance

Median Response Latency
type: PropertyValue
value reference: Performance

Requests Per Second (single instance)
type: PropertyValue
value reference: Performance

Time to Production (greenfield project)
type: PropertyValue
value reference: Development Speed

Initial Learning Hours
type: PropertyValue
value reference: Learning Curve

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

Memory Usage (hello world app)
type: PropertyValue
value reference: Resource Efficiency

TypeScript Support
type: PropertyValue
value reference: Development

Bundle Size (Minified)
type: PropertyValue
value reference: Performance

Dependency Injection
type: PropertyValue
value reference: Architecture

Built-in Security Features
type: PropertyValue
value reference: Security

GitHub Stars (Community Size)
type: PropertyValue
value reference: Community & Adoption

Initial Setup Time
type: PropertyValue
value reference: Operational Efficiency

Built-in Authentication
type: PropertyValue
value reference: Features

Job Queue/Background Tasks
type: PropertyValue
value reference: Features

Average Time-to-Production (Simple CRUD App)
type: PropertyValue
value reference: Productivity

Scalability for Microservices
type: PropertyValue
value reference: Architecture

Core Package Size
type: PropertyValue
value reference: Performance

Learning Curve (for intermediate Node.js developer)
type: PropertyValue
value reference: Usability

Built-in Validation
type: PropertyValue
value reference: Features

GraphQL Support
type: PropertyValue
value reference: Features