X2Y2

X2Y2 is an NFT marketplace and trading platform on Ethereum offering REST APIs for querying listings, offers, sales history, collection statistics, and executing NFT trades. It provides one of the lowest marketplace fees in the industry at 0.5% and includes an NFT-backed lending (Fi) API suite alongside its core marketplace API.

X2Y2 publishes 8 API contracts indexed on the APIs.io network, including Chain API, Contracts API, Events API, and 5 more. Tagged areas include NFT, Ethereum, Marketplace, Blockchain, and Web3.

The X2Y2 catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

X2Y2’s developer surface includes authentication, GitHub presence, documentation, API reference, and 5 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

26.9/100 thin ▬ flat Agent 28/100 agent aware Front door AI 3/6 light Heartbeat 0/100 dormant saas Full breakdown ↓
scored 2026-11-13 · rubric v0.28.0 · Show this score on your site →

3 published contracts

NFT Ethereum Marketplace Blockchain Web3 Collectibles Trading

Kin Score

Kin Score How this is scored →
scored 2026-11-13 · rubric v0.28.0

Composite quality — 26.9/100 · thin

Contract Quality 9.5 / 19

Developer Ergonomics 5.4 / 15

Access Clarity 0.0 / 15

Operational Transparency 0.5 / 10

Contract Governance 1.2 / 9

Discoverability 5.4 / 8

Regulatory Posture 1.5 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 28/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 6 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 7 / 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

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Securities & Market Data regime (on an ambiguous tag, where no other regime matched), 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 applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. 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/.

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

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship Ask about this →
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented) Ask about this →
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes Ask about this →
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0 Ask about this →
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document Ask about this →
Delegated User Identity +6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented) Ask about this →

7 more unmet checks in the Agent Readiness table above.

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

Access Clarity scores 0.0 — up to +20.0 composite points Ask about this →
Developer Ergonomics scores 35.7 — up to +12.9 composite points Ask about this →
Operational Transparency scores 4.8 — up to +12.4 composite points Ask about this →

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.

Not sure how this applies to your stack? Ask about any one item. Kin Lane reads every question, looks at your profile and your situation, and replies with what a fix would take — scoped to that one area, priced up front, yours whether you ship it or not. Ask a question →

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/x2y2/apis.yml: open an issue on github.com/api-evangelist/x2y2 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 →

Standards implemented 1

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.

OpenAPI

measured — observed by APIs.io (published)

APIs 8

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

X2Y2 Chain API

The Chain API from X2Y2 — 4 operation(s) for chain.

X2Y2 Contracts API

The Contracts API from X2Y2 — 2 operation(s) for contracts.

X2Y2 Events API

The Events API from X2Y2 — 1 operation(s) for events.

X2Y2 General API

The General API from X2Y2 — 1 operation(s) for general.

X2Y2 Loan API

The Loan API from X2Y2 — 1 operation(s) for loan.

X2Y2 Offer API

The Offer API from X2Y2 — 4 operation(s) for offer.

X2Y2 Offers API

The Offers API from X2Y2 — 1 operation(s) for offers.

X2Y2 Orders API

The Orders API from X2Y2 — 4 operation(s) for orders.

Scroll for all 8

Open Collections 8

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

X2Y2 Fi Chain API

OPEN COLLECTION

X2Y2 Fi Chain Contracts API

OPEN COLLECTION

X2Y2 Fi Chain Events API

OPEN COLLECTION

X2Y2 Fi Chain General API

OPEN COLLECTION

X2Y2 Fi Chain Loan API

OPEN COLLECTION

X2Y2 Fi Chain Offer API

OPEN COLLECTION

X2Y2 Fi Chain Offers API

OPEN COLLECTION

X2Y2 Fi Chain Orders API

OPEN COLLECTION

Scroll for all 8

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Apis Context

0 classes · 0 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs. Counts are the severity each rule declares, not results of running them.

X2Y2 API Rules

46 rules · 44 error-severity 1 warn-severity 1 info-severity

SPECTRAL

Security Posture 2

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

X2Y2 Authentication

apiKey · 3 schemes

SECURITY

X2Y2 Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Agentic Access (API Evangelist recommendations) 1

Recommended x-agentic-access execution contracts for AI agents.

X2Y2 Agentic Access

18 operations · 8 acting

AGENTIC

Resources

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 3

SDKs, sample code, and the tooling you integrate with

GitHub

GitHub

SDKs

SDKs

npm

npm

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Company 1

The organization behind the API

Website

Website

Source (apis.yml)

name: X2Y2
description: X2Y2 is an NFT marketplace and trading platform on Ethereum offering REST APIs for querying listings, offers,
  sales history, collection statistics, and executing NFT trades. It provides one of the lowest marketplace fees in the industry
  at 0.5% and includes an NFT-backed lending (Fi) API suite alongside its core marketplace API.
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - 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
  - security
  generated: '2026-11-13'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/x2y2.png
url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/apis.yml
created: '2024-01-01'
modified: '2026-09-16'
specificationVersion: '0.23'
x-docs-platform: readme
x-docs-platform-confidence: medium
x-docs-platform-checked: 2026-10-17
x-docs-hosting: vercel
tags:
- NFT
- Ethereum
- Marketplace
- Blockchain
- Web3
- Collectibles
- Trading
apis:
- aid: x2y2:x2y2-chain-api
  name: X2Y2 Chain API
  description: The Chain API from X2Y2 — 4 operation(s) for chain.
  humanURL: https://docs.x2y2.io/developers/api
  baseURL: https://loan-api.x2y2.org
  baseurl_source: contract
  tags:
  - Chain
  properties:
  - type: OpenAPI
    url: openapi/x2y2-chain-api-openapi.yml
  - type: Documentation
    url: https://docs.x2y2.io/developers/api
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/plans/plans.md
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/rate-limits/rate-limits.md
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/finops/finops.md
- aid: x2y2:x2y2-contracts-api
  name: X2Y2 Contracts API
  description: The Contracts API from X2Y2 — 2 operation(s) for contracts.
  humanURL: https://docs.x2y2.io/developers/api
  baseURL: https://api.x2y2.org
  tags:
  - Contracts
  properties:
  - type: OpenAPI
    url: openapi/x2y2-contracts-api-openapi.yml
  - type: Documentation
    url: https://docs.x2y2.io/developers/api
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/plans/plans.md
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/rate-limits/rate-limits.md
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/finops/finops.md
- aid: x2y2:x2y2-events-api
  name: X2Y2 Events API
  description: The Events API from X2Y2 — 1 operation(s) for events.
  humanURL: https://docs.x2y2.io/developers/api
  baseURL: https://api.x2y2.org
  tags:
  - Event
  tags_raw:
  - Events
  properties:
  - type: OpenAPI
    url: openapi/x2y2-events-api-openapi.yml
  - type: Documentation
    url: https://docs.x2y2.io/developers/api
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/plans/plans.md
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/rate-limits/rate-limits.md
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/finops/finops.md
- aid: x2y2:x2y2-general-api
  name: X2Y2 General API
  description: The General API from X2Y2 — 1 operation(s) for general.
  humanURL: https://docs.x2y2.io/developers/api
  baseURL: https://loan-api.x2y2.org
  baseurl_source: contract
  tags: []
  tags_raw:
  - General
  properties:
  - type: OpenAPI
    url: openapi/x2y2-general-api-openapi.yml
  - type: Documentation
    url: https://docs.x2y2.io/developers/api
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/plans/plans.md
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/rate-limits/rate-limits.md
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/finops/finops.md
- aid: x2y2:x2y2-loan-api
  name: X2Y2 Loan API
  description: The Loan API from X2Y2 — 1 operation(s) for loan.
  humanURL: https://docs.x2y2.io/developers/api
  baseURL: https://loan-api.x2y2.org
  baseurl_source: contract
  tags:
  - Loan
  properties:
  - type: OpenAPI
    url: openapi/x2y2-loan-api-openapi.yml
  - type: Documentation
    url: https://docs.x2y2.io/developers/api
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/plans/plans.md
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/rate-limits/rate-limits.md
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/finops/finops.md
- aid: x2y2:x2y2-offer-api
  name: X2Y2 Offer API
  description: The Offer API from X2Y2 — 4 operation(s) for offer.
  humanURL: https://docs.x2y2.io/developers/api
  baseURL: https://loan-api.x2y2.org
  baseurl_source: contract
  tags:
  - Offer
  properties:
  - type: OpenAPI
    url: openapi/x2y2-offer-api-openapi.yml
  - type: Documentation
    url: https://docs.x2y2.io/developers/api
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/plans/plans.md
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/rate-limits/rate-limits.md
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/finops/finops.md
- aid: x2y2:x2y2-offers-api
  name: X2Y2 Offers API
  description: The Offers API from X2Y2 — 1 operation(s) for offers.
  humanURL: https://docs.x2y2.io/developers/api
  baseURL: https://api.x2y2.org
  tags:
  - Offers
  properties:
  - type: OpenAPI
    url: openapi/x2y2-offers-api-openapi.yml
  - type: Documentation
    url: https://docs.x2y2.io/developers/api
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/plans/plans.md
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/rate-limits/rate-limits.md
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/finops/finops.md
- aid: x2y2:x2y2-orders-api
  name: X2Y2 Orders API
  description: The Orders API from X2Y2 — 4 operation(s) for orders.
  humanURL: https://docs.x2y2.io/developers/api
  baseURL: https://api.x2y2.org
  tags:
  - Order
  tags_raw:
  - Orders
  properties:
  - type: OpenAPI
    url: openapi/x2y2-orders-api-openapi.yml
  - type: Documentation
    url: https://docs.x2y2.io/developers/api
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/plans/plans.md
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/rate-limits/rate-limits.md
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/x2y2/refs/heads/main/finops/finops.md
common:
- type: Website
  url: https://x2y2.io
- type: AgenticAccess
  url: agentic-access/x2y2-agentic-access.yml
- type: DomainSecurity
  url: security/x2y2-domain-security.yml
- type: Authentication
  url: authentication/x2y2-authentication.yml
- type: GitHub
  url: https://github.com/X2Y2-io
- type: SDKs
  url: https://github.com/X2Y2-io/x2y2-sdk
- type: npm
  url: https://www.npmjs.com/package/@x2y2-io/sdk
- type: Documentation
  url: https://docs.x2y2.io/developers/api
- type: APIReference
  url: https://x2y2.readme.io/reference/introduction
maintainers:
- FN: API Evangelist
  url: https://apievangelist.com
  email: info@apievangelist.com

X2Y2 API — frequently asked questions

Does X2Y2 have an API?

Yes. APIs.io lists 8 APIs from X2Y2, including X2Y2 Chain API, X2Y2 Contracts API and X2Y2 Events API, and 5 more.

Is there an OpenAPI specification for the X2Y2 API?

Yes. APIs.io indexes 8 OpenAPI specifications for X2Y2, each linked for download from this page.

How do I authenticate with the X2Y2 API?

X2Y2 uses bearer-token authentication (apiKey · 3 schemes). The details are profiled on APIs.io as X2Y2 Authentication.

Is the X2Y2 API ready for AI agents?

X2Y2 has a Kin Score of 26.9 out of 100 (thin) and an Agent Readiness score of 28.2 (agent-aware), scored by API Evangelist on 2026-11-13.

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