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 6 APIs on the APIs.io network, including Email API, Id Resolution API, Identity API, and 3 more. Tagged areas include Company, Marketing, Personalization, Identity Resolution, and Email.

The Wunderkind catalog on APIs.io includes 1 event-driven AsyncAPI specification.

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

🌐 Visit website 📡 Source on GitHub

57.6/100 strong ▬ flat Agent 36/100 agent ready saas Full breakdown ↓
scored 2026-09-06 · rubric v0.19.0

5 APIs 1 MCP Servers

Company Marketing Personalization Identity Resolution Email SMS Behavioral Data E-Commerce Webhook

Kin Score

Kin Score How this is scored →
scored 2026-09-06 · rubric v0.19.0

Composite quality — 57.6/100 · strong

Contract Quality 12.4 / 21

Developer Ergonomics 10.4 / 17

Access Clarity 8.5 / 17

Operational Transparency 7.3 / 11

Contract Governance 1.9 / 10

Discoverability 6.9 / 9

Regulatory Posture 6.3 / 15

Agent readiness — 36/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 6 / 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 0 / 5

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.

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/.

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/wunderkind: 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 7

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

MCP Servers 1

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

Rate Limits 1

Documented rate limits and quota policies.

Examples 5

Example request and response payloads for these APIs.

Get Started 3

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

Login

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

LLMsTxt

MCPServer

AgentSkill

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Lifecycle

Webhooks

ErrorCatalog

Conventions

Conformance

DataModel

Build 8

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

Packages

SDKs

Examples

Examples

Examples

Examples

Examples

Scroll for all 8

Access & Security 4

Authentication, authorization, and security posture

DomainSecurity

Authentication

TrustCenter

Compliance

Operate 4

Status, limits, changes, and where to get help

Support

StatusPage

ChangeLog

RateLimits

Commercial 3

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Plans

Plans

Company 3

The organization behind the API

Website

Website

Blog

Blog

LinkedIn

Other 5

Properties that don't map to a standard resource type

CapabilityMap

Overlay

Overlay

Overlay

Overlay

Source (apis.yml)

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: '2026-09-03'
  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'
tags:
- Company
- Marketing
- Personalization
- Identity Resolution
- Email
- SMS
- Behavioral Data
- E-Commerce
- Webhook
tags_raw:
- Company
- Marketing
- Personalization
- Identity Resolution
- Email
- SMS
- Behavioral Data
- eCommerce
- Webhooks
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

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Wunderkind

APIs 7

Open Collections 7

MCP Servers 1

Pricing Plans 1

Rate Limits 1

Event Specifications 1

Examples 5

Security Posture 3

Agentic Access 1

Get Started 3

Documentation 2

Agent Surfaces 4

Design & Contract 6

Build 8

Access & Security 4

Operate 4

Commercial 3

Company 3

Other 5

Source (apis.yml)

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