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 publishes 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 documentation, authentication, support, and 22 more developer resources.

🌐 Visit website 📡 Source on GitHub

31.0/100 thin ▬ flat Agent 32/100 agent ready saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

4 APIs 1 MCP Servers

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 2026-09-08 · rubric v0.20.0

Composite quality — 31.0/100 · thin

Contract Quality 9.3 / 25

Developer Ergonomics 6.7 / 20

Access Clarity 5.5 / 20

Operational Transparency 1.4 / 13

Contract Governance 0.0 / 12

Discoverability 8.2 / 10

Agent readiness — 32/100 · 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 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 5 / 5

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.

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/underdog: 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 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 Server

MCP SERVER

Security Posture 1

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

Underdog Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

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 3

Status, limits, changes, and where to get help

Deprecation

Deprecation

RateLimits

RateLimits

Support

Support

Commercial 3

Pricing, plans, and the legal terms of use

Plans

Plans

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 1

The organization behind the API

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:
  - security
  generated: '2026-09-02'
  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: '2026-08-17'
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-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: ToolCrosswalk
    url: mcp/underdog-tool-crosswalk.yml
  - type: Documentation
    url: https://underdog.shop/agents.md
  - type: Specification
    url: https://ucp.dev/2026-04-08/specification/overview/
- aid: 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
- aid: 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
- aid: 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
  baseURL: https://underdog.shop
  tags:
  - JSON
  - Catalog
  - Product
  tags_raw:
  - JSON
  - Catalog
  - Products
  properties:
  - type: Documentation
    url: https://underdog.shop/llms.txt
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- 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: Deprecation
  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/

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