EasySize

EasySize is an AI-powered size-recommendation platform for fashion e-commerce, marketed as "Fit Quiz." It helps clothing, footwear, sportswear, and swimwear retailers reduce returns and increase conversion by giving shoppers a personalized size recommendation without asking them for body measurements. EasySize ships as a native Shopify app and as a JavaScript library ("web app") that merchants embed on non-Shopify storefronts; the library is configured with a merchant-specific shop_id and product context and renders an in-page Fit Quiz widget. Merchants wire order-tracking and return-tracking events back to EasySize so the recommendation algorithm can learn, and can capture emails and drive personalized flows through a Klaviyo integration. EasySize supports 11+ languages with auto-detection, multiple size formats (UK/EU/US/international/custom), unisex and gender-aware logic, and additional fit/width/length recommendations. The company was a portfolio company of 500 Global.

EasySize publishes 1 API on the APIs.io network. Tagged areas include Company, Fashion, E-Commerce, Size Recommendation, and FIT.

EasySize’s developer surface includes documentation, getting-started guide, support, engineering blog, pricing, signup flow, and 10 more developer resources.

🌐 Visit website 📡 Source on GitHub

27.1/100 thin ▬ flat Agent 0/100 human only Front door AI 2/6 trace saas Full breakdown ↓
scored 2026-09-25 · rubric v0.23.0

1 APIs

Company Fashion E-CommerceSize RecommendationFIT Retail Shopify Personalization Widgets JavaScript

Kin Score

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

Composite quality — 27.1/100 · thin

Contract Quality 0.0 / 21

Developer Ergonomics 7.7 / 17

Access Clarity 7.6 / 17

Operational Transparency 1.7 / 11

Contract Governance 0.0 / 10

Discoverability 6.2 / 9

Regulatory Posture 2.1 / 15

Agent readiness — 0/100 · 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 0 / 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.

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 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% 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/easysize: 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.

EasySize Fit Quiz JavaScript Library

Client-side JavaScript library that embeds the EasySize "Fit Quiz" size-recommendation widget on a merchant storefront. Loaded via a script tag from the EasySize web app CDN, it...

Security Posture 1

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

Easysize Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 3

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

SignUp

SignUp

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

WellKnown

WellKnown

Design & Contract 1

Pagination, idempotency, versioning, errors, and events

Lifecycle

Lifecycle

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Operate 3

Status, limits, changes, and where to get help

HelpCenter

HelpCenter

Support

Support

StatusPage

StatusPage

Commercial 3

Pricing, plans, and the legal terms of use

Pricing

Pricing

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Source (apis.yml)

aid: easysize
name: EasySize
description: EasySize is an AI-powered size-recommendation platform for fashion e-commerce, marketed as "Fit Quiz." It helps
  clothing, footwear, sportswear, and swimwear retailers reduce returns and increase conversion by giving shoppers a personalized
  size recommendation without asking them for body measurements. EasySize ships as a native Shopify app and as a JavaScript
  library ("web app") that merchants embed on non-Shopify storefronts; the library is configured with a merchant-specific
  shop_id and product context and renders an in-page Fit Quiz widget. Merchants wire order-tracking and return-tracking events
  back to EasySize so the recommendation algorithm can learn, and can capture emails and drive personalized flows through
  a Klaviyo integration. EasySize supports 11+ languages with auto-detection, multiple size formats (UK/EU/US/international/custom),
  unisex and gender-aware logic, and additional fit/width/length recommendations. The company was a portfolio company of 500
  Global.
url: https://raw.githubusercontent.com/api-evangelist/easysize/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- 500-global
x-tier: stub
x-tier-reason: portfolio-lead
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: false
  label: Hosted service · you call their endpoint
  confidence: medium
  source:
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source: []
  generated: '2026-07-22'
  method: derived
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-18'
image: https://cdn.prod.website-files.com/61fd2ddef6278cfc29072ae9/61fd48610cc67c01afaecfd3_easysize-logo.svg
tags:
- Company
- Fashion
- E-Commerce
- Size Recommendation
- FIT
- Retail
- Shopify
- Personalization
- Widgets
- JavaScript
tags_raw:
- Company
- Fashion
- E-Commerce
- Size Recommendation
- Fit
- Retail
- Shopify
- Personalization
- Widget
- JavaScript
apis:
- name: EasySize Fit Quiz JavaScript Library
  description: Client-side JavaScript library that embeds the EasySize "Fit Quiz" size-recommendation widget on a merchant
    storefront. Loaded via a script tag from the EasySize web app CDN, it exposes a global EasySize object configured with
    a merchant shop_id plus product context, and provides hooks for size selection, order tracking, and return tracking.
  humanURL: https://developers.easysize.me
  baseURL: https://webapp.easysize.me
  tags:
  - Size Recommendation
  - JavaScript
  - Widgets
  tags_raw:
  - Size Recommendation
  - JavaScript
  - Widget
  properties:
  - type: Documentation
    url: https://developers.easysize.me
  - type: GettingStarted
    url: https://developers.easysize.me/easysize_library/
  - type: Packages
    url: packages/easysize-packages.yml
  - type: SDKs
    url: packages/easysize-packages.yml
  - type: Components
    url: components/easysize-components.yml
  - type: Conventions
    url: conventions/easysize-conventions.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://easysize.me
- type: DeveloperPortal
  url: https://developers.easysize.me
- type: Documentation
  url: https://developers.easysize.me
- type: GettingStarted
  url: https://developers.easysize.me/easysize_library/
- type: HelpCenter
  url: https://help.easysize.me
- type: Support
  url: https://help.easysize.me
- type: Blog
  url: https://www.easysize.me/blog
- type: Pricing
  url: https://www.easysize.me/pricing
- type: TermsOfService
  url: https://www.easysize.me/terms-of-service
- type: PrivacyPolicy
  url: https://www.easysize.me/privacy-policy
- type: SignUp
  url: https://apps.shopify.com/fit-quiz
- type: StatusPage
  url: https://easysize.statuspage.io
- type: Lifecycle
  url: lifecycle/easysize-lifecycle.yml
- type: LLMsTxt
  url: llms/easysize-llms.txt
- type: WellKnown
  url: well-known/easysize-well-known.yml
- type: DomainSecurity
  url: security/easysize-domain-security.yml
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence

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