Flask website screenshot

Flask

Flask is a lightweight WSGI web application framework for Python, designed to make getting started quick and easy with the ability to scale up to complex applications. It provides a simple core with Jinja2 templating and Werkzeug WSGI toolkit, and is extensible through a rich ecosystem of extensions for database integration, form validation, authentication, and more. Flask is a popular foundation for building APIs and web services in Python.

Flask publishes 1 API on the APIs.io network. Tagged areas include Frameworks, Lightweight, Microframework, Pallets, and Python.

The Flask catalog on APIs.io includes 1 Spectral governance ruleset.

Flask’s developer surface includes documentation, getting-started guide, engineering blog, changelog, and 7 more developer resources.

🌐 Visit website 📡 Source on GitHub
34.4/100 thin ▬ flat Agent 3/100 human only Full breakdown ↓
scored 2026-07-28 · rubric v0.6
AccessFreemium
1 APIs
FrameworksLightweightMicroframeworkPalletsPythonWeb FrameworkWSGI

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-28 · rubric v0.6
Composite quality — 34.4/100 · thin
Contract Quality 2.4 / 25
Developer Ergonomics 4.3 / 20
Commercial Clarity 7.9 / 20
Operational Transparency 6.8 / 13
Governance 7.0 / 12
Discoverability 5.9 / 10
Agent readiness — 3/100 · human only
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 10
MCP Server 0 / 12
Machine-Readable Auth 0 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/flask: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 1

Individual APIs this provider publishes, each with its own machine-readable definition.

Flask

Flask is a lightweight WSGI web application framework for Python. It is commonly used as a foundation for building HTTP APIs and web services. While Flask itself does not expose...

Pricing Plans 1

Published pricing tiers and plan structures.

Flask Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Flask Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Flask Finops

FINOPS

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Flask API Rules

5 rules · 4 warnings 1 info

SPECTRAL

JSON Schema 1

Standalone JSON Schema definitions for this provider's data models.

Flask Application Configuration

42 properties

JSON SCHEMA

Security Posture 1

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Flask Domain Security

TLSv1.3

SECURITY

Resources

Get Started 1

Portal, sign-up, and the first successful call

GettingStarted
GettingStarted

Documentation 1

Reference material describing how the API behaves

Documentation
Documentation

Build 3

SDKs, sample code, and the tooling you integrate with

GitHubOrganization
GitHubOrganization
 SourceCode
SourceCode
 Extensions
Extensions

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity
DomainSecurity

Operate 1

Status, limits, changes, and where to get help

ChangeLog
ChangeLog

Commercial 1

Pricing, plans, and the legal terms of use

License
License

Company 2

The organization behind the API

Website
Website
 Blog
Blog

Other 1

Properties that don't map to a standard resource type

PyPI
PyPI

Source (apis.yml)

apis.yml Raw ↑ 
aid: flask
name: Flask
description: Flask is a lightweight WSGI web application framework for Python, designed to make getting started quick and
  easy with the ability to scale up to complex applications. It provides a simple core with Jinja2 templating and Werkzeug
  WSGI toolkit, and is extensible through a rich ecosystem of extensions for database integration, form validation, authentication,
  and more. Flask is a popular foundation for building APIs and web services in Python.
type: Index
accessModel:
  pricing: freemium
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Freemium
  confidence: medium
  source:
  - plans
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/flask.png
access: Open Source
position: Producer
tags:
- Frameworks
- Lightweight
- Microframework
- Pallets
- Python
- Web Framework
- WSGI
url: https://raw.githubusercontent.com/api-evangelist/flask/refs/heads/main/apis.yml
created: '2026-03-26'
modified: '2026-04-28'
specificationVersion: '0.19'
apis:
- aid: flask:flask
  name: Flask
  description: Flask is a lightweight WSGI web application framework for Python. It is commonly used as a foundation for building
    HTTP APIs and web services. While Flask itself does not expose an HTTP API, it ships with a configurable runtime whose
    configuration surface is captured here as a JSON Schema for tooling and validation purposes.
  humanURL: https://flask.palletsprojects.com/
  tags:
  - Frameworks
  - Lightweight
  - Microframework
  - Pallets
  - Python
  - Web Framework
  - WSGI
  properties:
  - type: Documentation
    url: https://flask.palletsprojects.com/en/stable/
  - type: GettingStarted
    url: https://flask.palletsprojects.com/en/stable/quickstart/
  - type: SourceCode
    url: https://github.com/pallets/flask
  - type: JSONSchema
    url: json-schema/flask-config.json
common:
- type: DomainSecurity
  url: security/flask-domain-security.yml
- type: Website
  url: https://flask.palletsprojects.com/
- type: Documentation
  url: https://flask.palletsprojects.com/en/stable/
- type: GettingStarted
  url: https://flask.palletsprojects.com/en/stable/quickstart/
- type: GitHubOrganization
  url: https://github.com/pallets
- type: SourceCode
  url: https://github.com/pallets/flask
- type: Blog
  url: https://palletsprojects.com/blog/
- type: PyPI
  url: https://pypi.org/project/flask/
- type: Extensions
  url: https://flask.palletsprojects.com/en/stable/extensions/
- type: ChangeLog
  url: https://flask.palletsprojects.com/en/stable/changes/
- type: License
  url: https://github.com/pallets/flask/blob/main/LICENSE.txt
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com