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 34 more developer resources.

🌐 Visit website 📡 Source on GitHub
54.8/100 developing ▬ flat Agent 57/100 agent ready Full breakdown ↓
scored 2026-08-17 · rubric v0.11.0
AccessSelf serve
7 APIs 1 MCP Servers
CompanyMarketingPersonalizationIdentity ResolutionEmailSMSBehavioral DataeCommerceWebhooks

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-08-17 · rubric v0.11.0
Composite quality — 54.8/100 · developing
Contract Quality 13.1 / 21
Developer Ergonomics 10.6 / 17
Commercial Clarity 8.5 / 17
Operational Transparency 7.3 / 11
Governance 1.2 / 10
Discoverability 7.9 / 9
Regulatory Posture 6.3 / 15
Agent readiness — 57/100 · agent ready
Machine-Readable Contract 18 / 18
Agentic Access Contract 10 / 10
MCP Server 12 / 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 4 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
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/. 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. Want it done for you? Prioritized profiling — $2,500 →

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 ...

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Open Collections 7

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

API Collection

OPEN COLLECTION

Wunderkind Email API

OPEN COLLECTION

Wunderkind Email Id Resolution API

OPEN COLLECTION

Wunderkind Email Identity API

OPEN COLLECTION

Wunderkind Email Send Event API

OPEN COLLECTION

Wunderkind Email Ucrm API

OPEN COLLECTION

Wunderkind Email Wunderhook API

OPEN COLLECTION

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MCP Servers 1

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

wunderkind-mcp.yml

MCP SERVER

Pricing Plans 1

Published pricing tiers and plan structures.

Wunderkind Plans Pricing

0 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Wunderkind Rate Limits

2 limits

RATE LIMITS

Event Specifications 1

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

Wunderkind Signals Webhooks

ASYNCAPI

Examples 5

Example request and response payloads for these APIs.

Wunderkind Identity Lookup Example

4 fields

EXAMPLE

Wunderkind Send Email Example

4 fields

EXAMPLE

Wunderkind Signals Webhook Delivery Example

5 fields

EXAMPLE

Wunderkind Subscribe Users Example

4 fields

EXAMPLE

Wunderkind Unsubscribe Users Example

4 fields

EXAMPLE

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

23 operations · 21 acting

23 operations · 21 acting

AGENTIC

Resources

Get Started 3

Portal, sign-up, and the first successful call

DeveloperPortal
DeveloperPortal
 GettingStarted
GettingStarted
 Login
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
AgenticAccess
 LLMsTxt
LLMsTxt
 MCPServer
MCPServer
 AgentSkill
AgentSkill

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Lifecycle
Lifecycle
 Webhooks
Webhooks
 ErrorCatalog
ErrorCatalog
 Conventions
Conventions
 Conformance
Conformance
 DataModel
DataModel

Build 8

SDKs, sample code, and the tooling you integrate with

GitHubOrganization
GitHubOrganization
 Packages
Packages
 SDKs
SDKs
 Examples
Examples
 Examples
Examples
 Examples
Examples
 Examples
Examples
 Examples
Examples

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Access & Security 4

Authentication, authorization, and security posture

DomainSecurity
DomainSecurity
 Authentication
Authentication
 TrustCenter
TrustCenter
 Compliance
Compliance

Operate 4

Status, limits, changes, and where to get help

Support
Support
 StatusPage
StatusPage
 ChangeLog
ChangeLog
 RateLimits
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
LinkedIn

Other 4

Properties that don't map to a standard resource type

Overlay
Overlay
 Overlay
Overlay
 Overlay
Overlay
 Overlay
Overlay

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
accessModel:
  pricing: unknown
  onboarding: self-serve
  trial: false
  try_now: false
  public: false
  label: Self-serve signup
  confidence: medium
  source:
  - authentication
  generated: '2026-07-22'
  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: '0.20'
created: '2026-07-17'
modified: '2026-08-13'
tags:
- 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: 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