Zulily

Zulily is an online retailer of daily deals on apparel, home, toys, and lifestyle goods. After its 2023 shutdown the brand was acquired and relaunched as a Shopify-hosted store. The relaunched storefront is agent-native: it implements the Universal Commerce Protocol (UCP) with a JSON-RPC MCP shopping endpoint, exposes OpenID Connect / OAuth 2.0 authentication via the Shopify Customer Account API (including a customer-account-mcp-api scope), and publishes an llms.txt / agents.md describing how AI shopping agents can discover products and run buyer-approved checkouts. This profile was surfaced as an a16z / Trinity Ventures portfolio company and enriched from Zulily's real public agent-commerce surface.

Zulily is listed with 2 APIs on the APIs.io network. Tagged areas include Company, E-Commerce, Retail, Shopping, and Commerce.

Zulily’s developer surface includes authentication and 11 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

21.1/100 emerging ▬ flat Agent 17/100 agent aware Front door AI 1/6 silent saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

2 APIs 1 MCP Servers 1 Agent Skills

Company E-Commerce Retail Shopping Commerce Agentic Commerce Universal Commerce Protocol MCP Shopify

Kin Score

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

Composite quality — 21.1/100 · emerging

Contract Quality 0.0 / 21

Developer Ergonomics 3.2 / 17

Access Clarity 3.6 / 17

Operational Transparency 1.2 / 11

Contract Governance 1.9 / 10

Discoverability 6.4 / 9

Regulatory Posture 4.3 / 15

Agent readiness — 17/100 · agent aware

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 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 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 0 / 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):

Machine-Readable Contract +18 pts — api_specs includes an OpenAPI document
Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
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)
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented)

8 more unmet checks in the Agent Readiness table above.

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

Contract Quality scores 0.0 — up to +25.0 composite points
Developer Ergonomics scores 19.0 — up to +16.2 composite points
Access Clarity scores 21.1 — up to +15.8 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/zulily/apis.yml: open an issue on github.com/api-evangelist/zulily 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 3

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.

Model Context Protocol (MCP)

measured — observed by APIs.io (platform)

Universal Commerce Protocol (UCP)

measured — observed by APIs.io (shopify)

Agent Skills

measured — observed by APIs.io (published)

APIs 2

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

Zulily UCP Shopping (MCP)

Zulily's agent-facing commerce API implementing the Universal Commerce Protocol (UCP) over a JSON-RPC MCP endpoint — search the catalog, build a cart, and run a buyer-approved c...

Zulily Customer Account API (Shopify)

OpenID Connect / OAuth 2.0 authentication and customer-account access for Zulily shoppers, provided by the Shopify Customer Account API, including an MCP-scoped agent surface.

MCP Servers 1

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

Zulily MCP Server

Remote MCP server at www.zulily.com over HTTP; 5 tools listed.

MCP SERVER

Agent Skills 1

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

Shop Zulily as an agent (UCP)

AGENT SKILL

Security Posture 1

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

Zulily Authentication

oauth2/openIdConnect · 1 scheme

SECURITY

Scopes 1

OAuth scopes governing access to this provider's APIs.

Zulily Scopes

4 scopes · authorizationCode

4 scopes

SCOPES

Resources

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

WellKnown

MCPServer

AgentSkill

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

Conformance

Conformance

Conventions

Conventions

Access & Security 3

Authentication, authorization, and security posture

SecurityTxt

SecurityTxt

Authentication

Authentication

OAuthScopes

OAuthScopes

Commercial 2

Pricing, plans, and the legal terms of use

PrivacyPolicy

PrivacyPolicy

TermsOfService

TermsOfService

Company 1

The organization behind the API

Website

Website

Source (apis.yml)

aid: zulily
name: Zulily
description: 'Zulily is an online retailer of daily deals on apparel, home, toys, and lifestyle goods. After its 2023 shutdown
  the brand was acquired and relaunched as a Shopify-hosted store. The relaunched storefront is agent-native: it implements
  the Universal Commerce Protocol (UCP) with a JSON-RPC MCP shopping endpoint, exposes OpenID Connect / OAuth 2.0 authentication
  via the Shopify Customer Account API (including a customer-account-mcp-api scope), and publishes an llms.txt / agents.md
  describing how AI shopping agents can discover products and run buyer-approved checkouts. This profile was surfaced as an
  a16z / Trinity Ventures portfolio company and enriched from Zulily''s real public agent-commerce surface.'
url: https://raw.githubusercontent.com/api-evangelist/zulily/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- a16z
- trinity-ventures
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:
  - authentication
  - scopes
  generated: '2026-11-06'
  method: derived
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-21'
image: https://www.zulily.com/favicon.ico
tags:
- Company
- E-Commerce
- Retail
- Shopping
- Commerce
- Agentic Commerce
- Universal Commerce Protocol
- MCP
- Shopify
tags_raw:
- Company
- Ecommerce
- Retail
- Shopping
- Commerce
- Agent Commerce
- Universal Commerce Protocol
- MCP
- Shopify
apis:
- name: Zulily UCP Shopping (MCP)
  description: Zulily's agent-facing commerce API implementing the Universal Commerce Protocol (UCP) over a JSON-RPC MCP endpoint
    — search the catalog, build a cart, and run a buyer-approved checkout.
  humanURL: https://www.zulily.com/llms.txt
  baseURL: https://www.zulily.com/api/ucp/mcp
  tags:
  - Commerce
  - MCP
  - Universal Commerce Protocol
  - Agentic Commerce
  tags_raw:
  - Commerce
  - MCP
  - UCP
  - Agent Commerce
  properties:
  - type: MCPServer
    url: mcp/zulily-mcp.yml
  - type: WellKnown
    url: well-known/zulily-well-known.yml
  - type: AgentSkill
    url: skills/_index.yml
  x-surface: platform-generated
  x-platform: shopify
  x-platform-surface: ucp
- name: Zulily Customer Account API (Shopify)
  description: OpenID Connect / OAuth 2.0 authentication and customer-account access for Zulily shoppers, provided by the
    Shopify Customer Account API, including an MCP-scoped agent surface.
  humanURL: https://shopify.dev/docs/api/customer
  baseURL: https://account.zulily.com/authentication
  tags:
  - Authentication
  - OAuth
  - OpenID Connect
  tags_raw:
  - Authentication
  - OAuth
  - OpenID Connect
  properties:
  - type: Authentication
    url: authentication/zulily-authentication.yml
  - type: OAuthScopes
    url: scopes/zulily-scopes.yml
  x-surface: platform-generated
  x-platform: shopify
  x-platform-surface: customer-account
common:
- type: Website
  url: https://www.zulily.com
- type: LLMsTxt
  url: llms/zulily-llms.txt
- type: WellKnown
  url: well-known/zulily-well-known.yml
- type: SecurityTxt
  url: llms/zulily-agents.md
- type: MCPServer
  url: mcp/zulily-mcp.yml
- type: Authentication
  url: authentication/zulily-authentication.yml
- type: OAuthScopes
  url: scopes/zulily-scopes.yml
- type: Conformance
  url: conformance/zulily-conformance.yml
- type: Conventions
  url: conventions/zulily-conventions.yml
- type: AgentSkill
  url: skills/_index.yml
- type: PrivacyPolicy
  url: https://www.zulily.com/policies/privacy-policy
- type: TermsOfService
  url: https://www.zulily.com/policies/terms-of-service
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io

Zulily API — frequently asked questions

Does Zulily have an API?

Yes. APIs.io lists 2 APIs from Zulily, including Zulily UCP Shopping (MCP) and Zulily Customer Account API (Shopify).

How do I authenticate with the Zulily API?

Zulily documents its authentication (oauth2/openIdConnect · 1 scheme). The details are profiled on APIs.io as Zulily Authentication.

Does Zulily have an MCP server?

Yes. APIs.io lists 1 MCP server for Zulily: Remote MCP server at www.zulily.com over HTTP; 5 tools listed.

Is the Zulily API ready for AI agents?

Zulily has a Kin Score of 21.1 out of 100 (emerging) and an Agent Readiness score of 17.4 (agent-aware), scored by API Evangelist on 2026-11-06.

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