Underdog

Underdog (legal entity Older is Better, RCS Nantes 918 609 629) is a French direct-to-consumer retailer of professionally refurbished large home appliances and televisions — washing machines, fridges, dishwashers, tumble dryers, ovens, cookers, freezers, wine cabinets, TVs and Thermomix — reconditioned in France and sold at up to 50% below new with a two-year warranty, delivery, installation and old-appliance takeback. It is a circular-economy / climate-tech company backed by Serena. Underdog has no developer programme and publishes no OpenAPI, but its storefront runs on Shopify and it exposes a genuine, live agent-commerce surface on its own domain: an /llms.txt and /agents.md agent instruction document, a Universal Commerce Protocol (UCP) merchant profile at /.well-known/ucp, two anonymously-listable remote MCP endpoints (a 13-tool UCP commerce server and a 1-tool storefront policy server), an introspectable Shopify Storefront GraphQL API, RFC 8414 / RFC 9728 OAuth metadata, and read-only product and collection JSON endpoints.

Underdog is listed with 4 APIs on the APIs.io network. Tagged areas include Company, Climate Tech, Circular Economy, Refurbished Electronics, and Home Appliances.

Underdog’s developer surface includes engineering blog, documentation, authentication, support, and 21 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

26.5/100 thin ▬ flat Agent 40/100 agent ready Front door AI 1/6 silent Heartbeat 0/100 dormant saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

4 APIs 1 MCP Servers 2 Agent Skills

Company Climate Tech Circular Economy Refurbished Electronics Home Appliances Retail E-Commerce Shopify Agentic Commerce Universal Commerce Protocol MCP GraphQL France

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 26.5/100 · thin

Contract Quality 2.0 / 21

Developer Ergonomics 5.2 / 17

Access Clarity 4.7 / 17

Operational Transparency 0.3 / 11

Contract Governance 1.9 / 10

Discoverability 6.1 / 9

Regulatory Posture 5.1 / 15

Agent readiness — 40/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 5 / 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 6 / 6

Protected Resource Metadata 5 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 5 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

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/.

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Agent readiness — checks not met, largest first (exact, from this profile):

Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document
Typed Event Surface +6 pts — AsyncAPI document, OR webhooks/callbacks objects in the as-published OpenAPI, OR common[].type includes Webhooks
Documented Reversibility +6 pts — a reversal operation in the contract, graded up when a window is documented too

3 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Contract Quality scores 9.3 — up to +22.7 composite points
Access Clarity scores 27.6 — up to +14.5 composite points
Developer Ergonomics scores 30.4 — up to +13.9 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

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 the provider profile at artifacts.apis.io/underdog/apis.yml: open an issue on github.com/api-evangelist/underdog to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Electronics Recycling & Circular Economy (e-waste, battery value chain, circularity networks)	undeclared	-	-	-

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

Standards implemented 4

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

GraphQL

tagged — the provider's own APIs.json carries the standard as a tag; implementation not verified

Model Context Protocol (MCP)

measured — observed by APIs.io (platform)

Universal Commerce Protocol (UCP)

measured — observed by APIs.io (shopify)

OAuth 2.0 Protected Resource Metadata

measured — observed by APIs.io (verified)

APIs 4

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

Underdog UCP Commerce MCP API

The Universal Commerce Protocol (UCP) shopping service Underdog serves from its own domain. A remote MCP endpoint that answers tools/list anonymously with 13 tools covering cata...

Underdog Storefront GraphQL API

The Shopify Storefront GraphQL API as served on underdog.shop. It answers introspection anonymously and exposes 424 types, 35 root query fields (products, collections, search, p...

Underdog Storefront Policy MCP API

A second remote MCP endpoint on underdog.shop that answers tools/list anonymously with a single natural-language tool, search_shop_policies_and_faqs, for questions about the sto...

Underdog Storefront JSON Endpoints

Read-only, unauthenticated JSON representations of the Underdog catalogue published by the Shopify storefront: /products.json, /products/{handle}.json, /collections/{handle}/pro...

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

Underdog MCP servers

Two remote MCP endpoints served from Underdog's own storefront host (Shopify platform). The UCP commerce server exposes 13 Universal Commerce Protocol shopping tools; the storef...

MCP SERVER

Agent Skills 2

Packaged agent skills for driving this provider's APIs from an AI assistant.

underdog-browse-catalog

AGENT SKILL

underdog-cart-and-checkout

AGENT SKILL

Underdog API pricing

Pricing Plans 1

Published pricing tiers and plan structures.

Underdog Plans Pricing

0 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Underdog Rate Limits

0 limits

RATE LIMITS

Security Posture 2

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

Underdog Authentication

none/oauth2/openIdConnect/http · 5 schemes

SECURITY

Underdog Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Scopes 1

OAuth scopes governing access to this provider's APIs.

Underdog Scopes

4 scopes · authorizationCode

4 scopes

SCOPES

Resources

Get Started 1

Portal, sign-up, and the first successful call

Login

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

GraphQL

GraphQL

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

WellKnown

MCPServer

AgentSkill

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Conformance

Conventions

Idempotency

ErrorCatalog

Lifecycle

DataModel

Build 2

SDKs, sample code, and the tooling you integrate with

ToolCrosswalk

ToolCrosswalk

GitHubOrganization

GitHubOrganization

Access & Security 3

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

OAuthScopes

OAuthScopes

Operate 2

Status, limits, changes, and where to get help

RateLimits

RateLimits

Support

Support

Commercial 3

Pricing, plans, and the legal terms of use

Plans

Plans

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Blog

Blog

Website

Website

Source (apis.yml)

aid: underdog
name: Underdog
description: 'Underdog (legal entity Older is Better, RCS Nantes 918 609 629) is a French direct-to-consumer retailer of professionally
  refurbished large home appliances and televisions — washing machines, fridges, dishwashers, tumble dryers, ovens, cookers,
  freezers, wine cabinets, TVs and Thermomix — reconditioned in France and sold at up to 50% below new with a two-year warranty,
  delivery, installation and old-appliance takeback. It is a circular-economy / climate-tech company backed by Serena. Underdog
  has no developer programme and publishes no OpenAPI, but its storefront runs on Shopify and it exposes a genuine, live agent-commerce
  surface on its own domain: an /llms.txt and /agents.md agent instruction document, a Universal Commerce Protocol (UCP) merchant
  profile at /.well-known/ucp, two anonymously-listable remote MCP endpoints (a 13-tool UCP commerce server and a 1-tool storefront
  policy server), an introspectable Shopify Storefront GraphQL API, RFC 8414 / RFC 9728 OAuth metadata, and read-only product
  and collection JSON endpoints.'
url: https://raw.githubusercontent.com/api-evangelist/underdog/refs/heads/main/apis.yml
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:
  - authentication
  - scopes
  - rate-limits
  - security
  generated: '2026-11-06'
  method: derived
image: https://underdog.shop/cdn/shop/files/UND-logo-Noir_1_3878927d-05f3-4209-b1e5-6113f92e6567.png?v=1762513808
x-type: company
x-source: serena-portfolio
x-tier: profiled
x-tier-reason: portfolio-lead
specificationVersion: '0.23'
created: '2026-08-17'
modified: '2026-10-06'
tags:
- Company
- Climate Tech
- Circular Economy
- Refurbished Electronics
- Home Appliances
- Retail
- E-Commerce
- Shopify
- Agentic Commerce
- Universal Commerce Protocol
- MCP
- GraphQL
- France
tags_raw:
- Company
- Climate Tech
- Circular Economy
- Refurbished Electronics
- Home Appliances
- Retail
- Ecommerce
- Shopify
- Agentic Commerce
- Universal Commerce Protocol
- MCP
- GraphQL
- France
apis:
- aid: underdog:underdog-ucp-commerce
  name: Underdog UCP Commerce MCP API
  description: The Universal Commerce Protocol (UCP) shopping service Underdog serves from its own domain. A remote MCP endpoint
    that answers tools/list anonymously with 13 tools covering catalog search and lookup, cart create/read/update/cancel,
    checkout create/read/update/complete/cancel, and order lookup. complete_checkout requires an idempotency-key and buyer
    approval. Merchant profile and supported protocol versions are published at https://underdog.shop/.well-known/ucp.
  humanURL: https://underdog.shop/agents.md
  baseURL: https://underdog.shop/api/ucp/mcp
  tags:
  - MCP
  - Agentic Commerce
  - Universal Commerce Protocol
  - Checkout
  - Catalog
  properties:
  - type: MCPServer
    url: mcp/underdog-mcp.yml
  - type: Authentication
    url: authentication/underdog-authentication.yml
  - type: Conventions
    url: conventions/underdog-conventions.yml
  - type: RateLimits
    url: rate-limits/underdog-rate-limits.yml
  - type: AgentSkill
    url: skills/_index.yml
  - type: ToolCrosswalk
    url: mcp/underdog-tool-crosswalk.yml
  - type: Documentation
    url: https://underdog.shop/agents.md
  - type: Specification
    url: https://ucp.dev/2026-08-25/specification/overview/
  x-surface: platform-generated
  x-platform: shopify
  x-platform-surface: ucp
- aid: underdog:underdog-storefront-graphql
  name: Underdog Storefront GraphQL API
  description: The Shopify Storefront GraphQL API as served on underdog.shop. It answers introspection anonymously and exposes
    424 types, 35 root query fields (products, collections, search, predictiveSearch, cart, blog/article, menu, metaobjects,
    shop, localization) and 41 mutations (cart lifecycle, customer accounts, Shop Pay payment request sessions) over Underdog's
    own catalogue, priced in EUR for FR.
  humanURL: https://underdog.shop/llms.txt
  baseURL: https://underdog.shop/api/2026-01/graphql.json
  tags:
  - GraphQL
  - Storefront
  - Catalog
  - Cart
  properties:
  - type: GraphQL
    url: graphql/underdog-storefront.graphql
  - type: DataModel
    url: data-model/underdog-data-model.yml
  - type: ErrorCatalog
    url: errors/underdog-problem-types.yml
  x-surface: platform-generated
  x-platform: shopify
  x-platform-surface: storefront-graphql
- aid: underdog:underdog-storefront-mcp
  name: Underdog Storefront Policy MCP API
  description: A second remote MCP endpoint on underdog.shop that answers tools/list anonymously with a single natural-language
    tool, search_shop_policies_and_faqs, for questions about the store's return, shipping, warranty and contact policies.
  humanURL: https://underdog.shop/agents.md
  baseURL: https://underdog.shop/api/mcp
  tags:
  - MCP
  - Support
  - Policies
  properties:
  - type: MCPServer
    url: mcp/underdog-mcp.yml
  x-surface: platform-generated
  x-platform: shopify
  x-platform-surface: storefront-mcp
- aid: underdog:underdog-storefront-json
  name: Underdog Storefront JSON Endpoints
  description: 'Read-only, unauthenticated JSON representations of the Underdog catalogue published by the Shopify storefront:
    /products.json, /products/{handle}.json, /collections/{handle}/products.json and /search?q=&type=product, plus /sitemap.xml
    and an agentic-discovery sitemap listing /agents.md.'
  humanURL: https://underdog.shop/llms.txt
  tags:
  - JSON
  - Catalog
  - Product
  tags_raw:
  - JSON
  - Catalog
  - Products
  properties:
  - type: Documentation
    url: https://underdog.shop/llms.txt
  x-surface: platform-generated
  x-platform: shopify
  x-platform-surface: storefront-json
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- url: https://underdog.shop/pages/blog
  type: Blog
- type: DomainSecurity
  url: security/underdog-domain-security.yml
- type: Website
  url: https://underdog.shop/
- type: Documentation
  url: https://underdog.shop/agents.md
- type: LLMsTxt
  url: llms/underdog-llms.txt
- type: WellKnown
  url: well-known/underdog-well-known.yml
- type: MCPServer
  url: mcp/underdog-mcp.yml
- type: ToolCrosswalk
  url: mcp/underdog-tool-crosswalk.yml
- type: GraphQL
  url: graphql/underdog-storefront.graphql
- type: Authentication
  url: authentication/underdog-authentication.yml
- type: OAuthScopes
  url: scopes/underdog-scopes.yml
- type: Conformance
  url: conformance/underdog-conformance.yml
- type: Conventions
  url: conventions/underdog-conventions.yml
- type: Idempotency
  url: conventions/underdog-conventions.yml
- type: ErrorCatalog
  url: errors/underdog-problem-types.yml
- type: Lifecycle
  url: lifecycle/underdog-lifecycle.yml
- type: DataModel
  url: data-model/underdog-data-model.yml
- type: Plans
  url: plans/underdog-plans-pricing.yml
- type: RateLimits
  url: rate-limits/underdog-rate-limits.yml
- type: AgentSkill
  url: skills/_index.yml
- type: GitHubOrganization
  url: https://github.com/underdog-shop
- type: Support
  url: https://underdog.shop/pages/contact
- type: TermsOfService
  url: https://underdog.shop/policies/terms-of-service
- type: PrivacyPolicy
  url: https://underdog.shop/policies/privacy-policy
- type: Login
  url: https://account.underdog.shop/
x-enrichment:
  date: '2026-09-16'
  status: enriched
  artifacts_added: 17
  pass: local-v3

Underdog API — frequently asked questions

Does Underdog have an API?

Yes. APIs.io lists 4 APIs from Underdog, including Underdog UCP Commerce MCP API, Underdog Storefront GraphQL API and Underdog Storefront Policy MCP API, and 1 more.

How do I authenticate with the Underdog API?

Underdog documents its authentication (none/oauth2/openIdConnect/http · 5 schemes). The details are profiled on APIs.io as Underdog Authentication.

Does Underdog have an MCP server?

Yes. APIs.io lists 1 MCP server for Underdog: Two remote MCP endpoints served from Underdog's own storefront host (Shopify platform). The UCP commerce server exposes 13 Universal Commerce Protocol shopping tools; the storefront server exposes one

Is the Underdog API ready for AI agents?

Underdog has a Kin Score of 26.5 out of 100 (thin) and an Agent Readiness score of 39.9 (agent-ready), scored by API Evangelist on 2026-11-06.

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