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 Framework, 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 11 more developer resources.

🌐 Visit website 📡 Source on GitHub

23.1/100 emerging ▬ flat Agent 3/100 human only Front door AI 1/6 silent self hosted · BSD-3-Clause Full breakdown ↓
scored 2026-09-25 · rubric v0.23.0

AccessFreemium

1 APIs

FrameworkLightweightMicroframework pallets Python Web Framework WSGI

Kin Score

Kin Score How this is scored →
scored 2026-09-25 · rubric v0.23.0

Composite quality — 23.1/100 · emerging

Contract Quality 1.4 / 19

Developer Ergonomics 3.6 / 15

Access Clarity 2.4 / 15

Operational Transparency 2.6 / 10

Contract Governance 0.9 / 9

Discoverability 4.3 / 8

Regulatory Posture 0.9 / 15

Open Source Surface 6.5 / 10

Agent readiness — 3/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

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

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Open Source Surface applies to this provider. This product is open source and we read its repository directly, so Open Source Surface carries 10 points of the composite. It is scored from what the repository actually publishes — a security policy, a contribution guide, a release history, a code of conduct — read live from the provider rather than inferred from our own catalog pointers. This facet adds; nothing was taken away to make room for it. An open-source project is not excused from the commercial facets, because exemption would strip it of the points it does earn. If we have the wrong repository, or this product is not open source, say so on your provider repo and we will drop the facet rather than have you publish against it.

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

The six quality facets above are damped to 75 points between them, because both conditional facets apply and carry 25 points together. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. 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. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

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 2

Reference material describing how the API behaves

ContributionGuide

ContributionGuide

Documentation

Documentation

Build 4

SDKs, sample code, and the tooling you integrate with

CodeOfConduct

CodeOfConduct

GitHubOrganization

GitHubOrganization

SourceCode

SourceCode

Extensions

Extensions

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Operate 3

Status, limits, changes, and where to get help

IssueTracker

IssueTracker

Releases

Releases

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)

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
deliveryModel:
  model: self-hosted
  license: BSD-3-Clause
  license_evidence:
    repo: pallets/flask
    spdx: BSD-3-Clause
    stars: 74777
  open_source: true
  commercial: false
  callable_host: false
  label: Self-hosted open source · you run it yourself
  confidence: medium
  source:
  - repository-license
  generated: '2026-09-25'
  method: derived
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: Producing
tags:
- Framework
- Lightweight
- Microframework
- pallets
- Python
- Web Framework
- WSGI
tags_raw:
- 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: '0.23'
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:
  - Framework
  - Lightweight
  - Microframework
  - pallets
  - Python
  - Web Framework
  - WSGI
  tags_raw:
  - 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: IssueTracker
  url: https://github.com/pallets/flask/issues
- type: Releases
  url: https://github.com/pallets/flask/releases
- type: CodeOfConduct
  url: https://github.com/pallets/.github/blob/main/CODE_OF_CONDUCT.md
- type: ContributionGuide
  url: https://github.com/pallets/flask/blob/main/docs/contributing.rst
- 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

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