Wunderkind website screenshot

Wunderkind

Wunderkind (formerly BounceX) is a performance marketing and identity resolution platform that turns anonymous website and mobile-app traffic into triggered, one-to-one email and text messages. Its Autonomous Marketing Platform pairs an identity graph with AI decisioning, and its Build with Wunderkind developer surface exposes that machinery as APIs: an Identity API for device-ID-to-email resolution, an Event Ingestion API for server-side behavioral events, Email and Text Message send APIs, a UCRM subscribe and unsubscribe API, Signals webhooks that deliver behavioral triggers into ESPs like Klaviyo, Salesforce Marketing Cloud, Braze, and Bloomreach, plus Web and Mobile SDKs for Android, iOS, Flutter, and React Native.

Wunderkind publishes 7 API contracts indexed on the APIs.io network, including Email API, Id Resolution API, Identity API, and 4 more. Tagged areas include Company, Marketing, Personalization, Identity Resolution, and Email.

The Wunderkind catalog on APIs.io includes 1 event-driven AsyncAPI specification and 1 Spectral governance ruleset.

Wunderkind’s developer surface includes authentication, documentation, API reference, getting-started guide, support, engineering blog, changelog, and 35 more developer resources.

59.4/100 strong ▬ flat Agent 35/100 agent ready Front door AI 5/6 prominent Heartbeat 64/100 alive saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →
5 published contracts 1 MCP Servers 4 Agent Skills
CompanyMarketingPersonalizationIdentity ResolutionEmailSMSBehavioral DataE-CommerceWebhookArtificial IntelligenceIdentity

What this lets a business do 3

Business capabilities this provider's published APIs can perform, derived from its own contracts. Browse all capabilities →

Customer Relationship Management
BC-420
Id ResolutionIdentity
POST /id-resolution/v1/identity/lookup/batch POST /v1/identity/lookup
Application Communications
AE-150
Email
POST /email/send
Application Identity & Verification
AE-160
Ucrm
PUT /ucrm/v1/unsubscribe

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0
Regulatory Posture applies to this provider. Its tags matched the Telecommunications 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 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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Raise your score.
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
  • 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)
  • A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
  • Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document
  • 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)
  • Documented Reversibility +6 pts — a reversal operation in the contract, graded up when a window is documented too
6 more unmet checks in the Agent Readiness table above.
Kin Score — facets with the most composite points still available (weight × headroom):
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/wunderkind/apis.yml: open an issue on github.com/api-evangelist/wunderkind 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.

MarketPositionDepthRegistered MCP serverDeclares compatibility
MACH & Headless Commerce standard 51.7 - -

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 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.

measured — observed by APIs.io (published)

APIs 7

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

Wunderkind Text Message API

RESTful endpoints for delivering text messages from platforms external to the Wunderkind ecosystem (ESP, CDP, etc.): single and bulk sends of up to 50,000 messages per request, ...

Wunderkind Email API

Email sending operations

Wunderkind Id Resolution API

The Id Resolution API from Wunderkind — 3 operation(s) for id resolution.

Wunderkind Identity API

The Identity API from Wunderkind — 2 operation(s) for identity.

Wunderkind Send Event API

The Send Event API from Wunderkind — 11 operation(s) for send event.

Wunderkind Ucrm API

The Ucrm API from Wunderkind — 2 operation(s) for ucrm.

Wunderkind Wunderhook API

The Signals Wunderhook consumer contract — the single POST endpoint a client stands up to RECEIVE Wunderkind Signals webhook deliveries. The base URL is therefore templated and ...

Scroll for all 7

Open Collections 6

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

Wunderkind Email API

OPEN COLLECTION

Wunderkind Email Ucrm API

OPEN COLLECTION

MCP Servers 1

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

Wunderkind MCP Server

Remote MCP server over HTTP; 16 tools listed. A candidate, not confirmed as published by the provider.

MCP SERVER

Agent Skills 4

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

Wunderkind API pricing

Pricing Plans 1

Published pricing tiers and plan structures.

Rate Limits 1

Documented rate limits and quota policies.

Wunderkind Rate Limits

2 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Wunderkind API Rules

43 rules · 36 errors 6 warnings 1 info

SPECTRAL

OpenAPI Overlays 4

Overlays applied on top of this provider's contracts. Each card says who wrote it: a document the provider publishes, or one API Evangelist derived or generated.

Wunderkind Email Overlay

3 actions · update · wunderkind-email-openapi.yml

DERIVED

Wunderkind Event Ingestion Overlay

3 actions · update · wunderkind-event-ingestion-openapi.yml

DERIVED

Wunderkind Identity Overlay

4 actions · update · wunderkind-identity-openapi.yml

DERIVED

Wunderkind Ucrm Overlay

4 actions · update · wunderkind-ucrm-openapi.yml

DERIVED

Examples 5

Example request and response payloads for these APIs.

Security Posture 3

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

Wunderkind Authentication

apiKey/http · 4 schemes

SECURITY

Wunderkind Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Wunderkind Trust Center

SOC 2 Type 2, ISO 27001

SECURITY

Agentic Access 1

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

Wunderkind Agentic Access

21 operations · 17 acting

21 operations · 17 acting

AGENTIC

Resources

Get Started 3

Portal, sign-up, and the first successful call

Documentation 2

Reference material describing how the API behaves

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Build 8

SDKs, sample code, and the tooling you integrate with

Scroll for all 8

Access & Security 4

Authentication, authorization, and security posture

Operate 4

Status, limits, changes, and where to get help

Commercial 3

Pricing, plans, and the legal terms of use

Company 3

The organization behind the API

Other 5

Properties that don't map to a standard resource type

Source (apis.yml)

apis.yml Raw ↑
aid: wunderkind
name: Wunderkind
description: 'Wunderkind (formerly BounceX) is a performance marketing and identity resolution platform that turns anonymous
  website and mobile-app traffic into triggered, one-to-one email and text messages. Its Autonomous Marketing Platform pairs
  an identity graph with AI decisioning, and its Build with Wunderkind developer surface exposes that machinery as APIs: an
  Identity API for device-ID-to-email resolution, an Event Ingestion API for server-side behavioral events, Email and Text
  Message send APIs, a UCRM subscribe and unsubscribe API, Signals webhooks that deliver behavioral triggers into ESPs like
  Klaviyo, Salesforce Marketing Cloud, Braze, and Bloomreach, plus Web and Mobile SDKs for Android, iOS, Flutter, and React
  Native.'
url: https://raw.githubusercontent.com/api-evangelist/wunderkind/refs/heads/main/apis.yml
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
  probe_state: covered
  source:
  - authentication
  - rate-limits
  - security
  generated: '2026-11-06'
  method: derived
image: https://avatars.githubusercontent.com/u/197307309?v=4
x-type: company
x-source: vc-portfolio
x-backed-by:
- battery-ventures
x-tier: full
x-tier-reason: enriched-provider
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-08-13'
x-docs-platform: readme
x-docs-platform-confidence: high
x-docs-platform-checked: 2026-10-17
tags:
- Company
- Marketing
- Personalization
- Identity Resolution
- Email
- SMS
- Behavioral Data
- E-Commerce
- Webhook
- Artificial Intelligence
- Identity
tags_raw:
- Company
- Marketing
- Personalization
- Identity Resolution
- Email
- SMS
- Behavioral Data
- eCommerce
- Webhooks
- Artificial Intelligence
- Identity
apis:
- aid: wunderkind:wunderkind-text-message-api
  name: Wunderkind Text Message API
  description: 'RESTful endpoints for delivering text messages from platforms external to the Wunderkind ecosystem (ESP, CDP,
    etc.): single and bulk sends of up to 50,000 messages per request, message status lookup, subscription status checks,
    and subscribe/unsubscribe of phone numbers. Authenticated with X-Client-ID and X-Client-Secret headers; rate limited to
    300 requests per second per website. No OpenAPI is published for this API; the reference is markdown documentation.'
  humanURL: https://developer.wunderkind.co/reference/text-message-api
  baseURL: https://api.wknd.ai
  tags:
  - SMS
  - Messaging
  properties:
  - url: https://developer.wunderkind.co/reference/text-message-api
    type: APIReference
  - url: https://developer.wunderkind.co/reference/bulk-text-message-api
    type: Documentation
- aid: wunderkind:wunderkind-email-api
  name: Wunderkind Email API
  description: Email sending operations
  humanURL: https://developer.wunderkind.co/reference/sendemail
  baseURL: https://api.wunderkind.co
  tags:
  - Email
  properties:
  - type: OpenAPI
    url: openapi/wunderkind-email-api-openapi.yml
  - type: APIReference
    url: https://developer.wunderkind.co/reference/sendemail
  - type: Documentation
    url: https://developer.wunderkind.co/reference/identity-api
  - type: APIReference
    url: https://developer.wunderkind.co/reference/batch-id-lookup
  - type: APIReference
    url: https://developer.wunderkind.co/reference/external_subscribe
  - type: Documentation
    url: https://developer.wunderkind.co/docs/event-ingestion-api-guide
  - type: APIReference
    url: https://developer.wunderkind.co/reference/service_visit
- aid: wunderkind:wunderkind-id-resolution-api
  name: Wunderkind Id Resolution API
  description: The Id Resolution API from Wunderkind — 3 operation(s) for id resolution.
  humanURL: https://developer.wunderkind.co/reference/batch-id-lookup
  baseURL: https://api.wunderkind.co
  tags:
  - Id Resolution
  properties:
  - type: OpenAPI
    url: openapi/wunderkind-id-resolution-api-openapi.yml
  - type: APIReference
    url: https://developer.wunderkind.co/reference/sendemail
  - type: Documentation
    url: https://developer.wunderkind.co/reference/identity-api
  - type: APIReference
    url: https://developer.wunderkind.co/reference/batch-id-lookup
  - type: APIReference
    url: https://developer.wunderkind.co/reference/external_subscribe
  - type: Documentation
    url: https://developer.wunderkind.co/docs/event-ingestion-api-guide
  - type: APIReference
    url: https://developer.wunderkind.co/reference/service_visit
- aid: wunderkind:wunderkind-identity-api
  name: Wunderkind Identity API
  description: The Identity API from Wunderkind — 2 operation(s) for identity.
  humanURL: https://developer.wunderkind.co/reference/identity-api
  baseURL: https://api.wunderkind.co
  tags:
  - Identity
  properties:
  - type: OpenAPI
    url: openapi/wunderkind-identity-api-openapi.yml
  - type: APIReference
    url: https://developer.wunderkind.co/reference/sendemail
  - type: Documentation
    url: https://developer.wunderkind.co/reference/identity-api
  - type: APIReference
    url: https://developer.wunderkind.co/reference/batch-id-lookup
  - type: APIReference
    url: https://developer.wunderkind.co/reference/external_subscribe
  - type: Documentation
    url: https://developer.wunderkind.co/docs/event-ingestion-api-guide
  - type: APIReference
    url: https://developer.wunderkind.co/reference/service_visit
- aid: wunderkind:wunderkind-send-event-api
  name: Wunderkind Send Event API
  description: The Send Event API from Wunderkind — 11 operation(s) for send event.
  humanURL: https://developer.wunderkind.co/docs/event-ingestion-api-guide
  baseURL: https://api.wunderkind.co
  tags:
  - Send Event
  properties:
  - type: OpenAPI
    url: openapi/wunderkind-send-event-api-openapi.yml
  - type: APIReference
    url: https://developer.wunderkind.co/reference/sendemail
  - type: Documentation
    url: https://developer.wunderkind.co/reference/identity-api
  - type: APIReference
    url: https://developer.wunderkind.co/reference/batch-id-lookup
  - type: APIReference
    url: https://developer.wunderkind.co/reference/external_subscribe
  - type: Documentation
    url: https://developer.wunderkind.co/docs/event-ingestion-api-guide
  - type: APIReference
    url: https://developer.wunderkind.co/reference/service_visit
- aid: wunderkind:wunderkind-ucrm-api
  name: Wunderkind Ucrm API
  description: The Ucrm API from Wunderkind — 2 operation(s) for ucrm.
  humanURL: https://developer.wunderkind.co/reference/external_subscribe
  baseURL: https://api.wunderkind.co
  tags:
  - Ucrm
  properties:
  - type: OpenAPI
    url: openapi/wunderkind-ucrm-api-openapi.yml
  - type: APIReference
    url: https://developer.wunderkind.co/reference/sendemail
  - type: Documentation
    url: https://developer.wunderkind.co/reference/identity-api
  - type: APIReference
    url: https://developer.wunderkind.co/reference/batch-id-lookup
  - type: APIReference
    url: https://developer.wunderkind.co/reference/external_subscribe
  - type: Documentation
    url: https://developer.wunderkind.co/docs/event-ingestion-api-guide
  - type: APIReference
    url: https://developer.wunderkind.co/reference/service_visit
- aid: wunderkind:wunderkind-wunderhook-api
  name: Wunderkind Wunderhook API
  description: The Signals Wunderhook consumer contract — the single POST endpoint a client stands up to RECEIVE Wunderkind
    Signals webhook deliveries. The base URL is therefore templated and client-owned (https://{yourendpoint}), not a Wunderkind-operated
    host; Wunderkind is the sender. Deliveries are authenticated with static headers or Basic auth from a published 20-address
    IP allowlist, with no HMAC signing.
  humanURL: https://developer.wunderkind.co/reference/signalswebhook
  baseURL: https://{yourendpoint}
  tags:
  - Wunderhook
  properties:
  - type: OpenAPI
    url: openapi/wunderkind-wunderhook-api-openapi.yml
  - type: APIReference
    url: https://developer.wunderkind.co/reference/sendemail
  - type: Documentation
    url: https://developer.wunderkind.co/reference/identity-api
  - type: APIReference
    url: https://developer.wunderkind.co/reference/batch-id-lookup
  - type: APIReference
    url: https://developer.wunderkind.co/reference/external_subscribe
  - type: Documentation
    url: https://developer.wunderkind.co/docs/event-ingestion-api-guide
  - type: APIReference
    url: https://developer.wunderkind.co/reference/service_visit
common:
- type: CapabilityMap
  url: capabilities/wunderkind-capability-edges.yml
  name: Wunderkind Business Capability Map
- type: Overlay
  url: overlays/wunderkind-email-overlay.yaml
- type: Overlay
  url: overlays/wunderkind-identity-overlay.yaml
- type: Overlay
  url: overlays/wunderkind-ucrm-overlay.yaml
- type: Overlay
  url: overlays/wunderkind-event-ingestion-overlay.yaml
- type: AgenticAccess
  url: agentic-access/wunderkind-agentic-access.yml
- type: DomainSecurity
  url: security/wunderkind-domain-security.yml
- type: Authentication
  url: authentication/wunderkind-authentication.yml
- url: https://www.wunderkind.co
  type: Website
- url: https://developer.wunderkind.co/
  type: DeveloperPortal
- url: https://developer.wunderkind.co/docs
  type: Documentation
- url: https://developer.wunderkind.co/reference
  type: APIReference
- url: https://developer.wunderkind.co/docs/msdk-getting-started
  type: GettingStarted
- url: https://support.wunderkind.co/hc
  type: Support
- url: https://www.wunderkind.co/blog/
  type: Blog
- url: https://github.com/wunderkind-oss
  type: GitHubOrganization
- url: https://platform.wunderkind.co
  type: Login
- url: https://www.wunderkind.co/terms/
  type: TermsOfService
- url: https://www.wunderkind.co/privacy/
  type: PrivacyPolicy
- url: https://status.wunderkind.co
  type: StatusPage
- url: https://www.linkedin.com/company/bewunderkind/
  type: LinkedIn
- url: changelog/wunderkind-changelog.yml
  type: ChangeLog
- url: lifecycle/wunderkind-lifecycle.yml
  type: Lifecycle
- url: asyncapi/wunderkind-signals-webhooks.yml
  type: Webhooks
- url: packages/wunderkind-packages.yml
  type: Packages
- url: packages/wunderkind-packages.yml
  type: SDKs
- url: llms/wunderkind-llms.txt
  type: LLMsTxt
- url: mcp/wunderkind-mcp.yml
  type: MCPServer
- url: errors/wunderkind-problem-types.yml
  type: ErrorCatalog
- url: conventions/wunderkind-conventions.yml
  type: Conventions
- url: conformance/wunderkind-conformance.yml
  type: Conformance
- url: data-model/wunderkind-data-model.yml
  type: DataModel
- url: rate-limits/wunderkind-rate-limits.yml
  type: RateLimits
- url: skills/_index.yml
  type: AgentSkill
- url: security/wunderkind-trust-center.yml
  type: TrustCenter
- url: plans/wunderkind-plans-pricing.yml
  type: Plans
- url: https://www.wunderkind.co/blog/article/wunderkinds-commitment-to-privacy-compliance/
  type: Compliance
- url: examples/wunderkind-send-email-example.json
  type: Examples
- url: examples/wunderkind-subscribe-users-example.json
  type: Examples
- url: examples/wunderkind-unsubscribe-users-example.json
  type: Examples
- url: examples/wunderkind-identity-lookup-example.json
  type: Examples
- url: examples/wunderkind-signals-webhook-delivery-example.json
  type: Examples
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-08-13'
  status: enriched
  artifacts_added: 6
  pass: local-v1
x-coverage:
  state: covered

Wunderkind API — frequently asked questions

Does Wunderkind have an API?

Yes. APIs.io lists 7 APIs from Wunderkind, including Wunderkind Text Message API, Wunderkind Email API and Wunderkind Id Resolution API, and 4 more.

Is there an OpenAPI specification for the Wunderkind API?

Yes. APIs.io indexes 6 OpenAPI specifications for Wunderkind, each linked for download from this page.

How do I authenticate with the Wunderkind API?

Wunderkind uses bearer-token authentication (apiKey/http · 4 schemes). The details are profiled on APIs.io as Wunderkind Authentication.

Does Wunderkind have an MCP server?

Yes. APIs.io lists 1 MCP server for Wunderkind: Remote MCP server over HTTP; 16 tools listed. A candidate, not confirmed as published by the provider.

Is the Wunderkind API ready for AI agents?

Wunderkind has a Kin Score of 59.4 out of 100 (strong) and an Agent Readiness score of 35.0 (agent-ready), scored by API Evangelist on 2026-11-06.

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