Halliday

Halliday is a web3 payments and agentic-workflow company (a16z crypto Series A) building the end-to-end onchain deposit platform. Its Agentic Workflow Protocol (AWP) lets developers compose high-level, AI-executable workflows behind immutable guardrails without writing smart-contract code. The flagship product, Halliday Payments, is a unified cross-chain payments API and drop-in widget that lets users onramp from fiat, bridge, and swap to acquire any asset on any chain in a fully self-custodial way, routing intelligently across onramps (MoonPay, Transak, Stripe), swaps, and bridges. The Halliday API V2 (https://v2.prod.halliday.xyz) exposes chains, assets, quotes, payments, balances, withdrawals, and signed workflow webhooks, authenticated with publishable API keys, alongside JS/React/React Native SDKs and a published Claude Code integration skill.

Halliday publishes 4 APIs on the APIs.io network, including Assets API, Chains API, Payments API, and 1 more. Tagged areas include Company, Payments, Cryptocurrency, Blockchain, and Web3.

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

Halliday’s developer surface includes documentation, API reference, getting-started guide, support, engineering blog, signup flow, sandbox, and 22 more developer resources.

🌐 Visit website 📡 Source on GitHub

51.8/100 developing ▬ flat Agent 36/100 agent ready saas Full breakdown ↓
scored 2026-08-30 · rubric v0.17.2

AccessSelf serve

1 APIs 1 MCP Servers

Company Payments Cryptocurrency Blockchain Web3OnrampSwaps DeFi Agentic Workflows Fintech

Kin Score

Kin Score How this is scored →
scored 2026-08-30 · rubric v0.17.2

Composite quality — 51.8/100 · developing

Contract Quality 15.3 / 21

Developer Ergonomics 12.5 / 17

Access Clarity 4.9 / 17

Operational Transparency 1.2 / 11

Contract Governance 1.9 / 10

Discoverability 6.5 / 9

Regulatory Posture 7.0 / 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 0 / 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 Surface 0 / 5

Regulatory Posture applies to this provider. Its tags matched the Payments 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/halliday: 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 4

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.

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal

GettingStarted

SignUp

Sandbox

Documentation 3

Reference material describing how the API behaves

OpenAPI

OpenAPI

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

MCPServer

LLMsTxt

AgentSkill

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Conformance

ErrorCatalog

Lifecycle

Conventions

Components

DataModel

Webhooks

Scroll for all 7

Build 3

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Packages

Packages

SDKs

SDKs

Access & Security 3

Authentication, authorization, and security posture

Compliance

Compliance

Authentication

Authentication

DomainSecurity

DomainSecurity

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 1

The organization behind the API

Blog

Blog

Other 1

Properties that don't map to a standard resource type

Overlay

Overlay

Source (apis.yml)

aid: halliday
name: Halliday
description: Halliday is a web3 payments and agentic-workflow company (a16z crypto Series A) building the end-to-end onchain
  deposit platform. Its Agentic Workflow Protocol (AWP) lets developers compose high-level, AI-executable workflows behind
  immutable guardrails without writing smart-contract code. The flagship product, Halliday Payments, is a unified cross-chain
  payments API and drop-in widget that lets users onramp from fiat, bridge, and swap to acquire any asset on any chain in
  a fully self-custodial way, routing intelligently across onramps (MoonPay, Transak, Stripe), swaps, and bridges. The Halliday
  API V2 (https://v2.prod.halliday.xyz) exposes chains, assets, quotes, payments, balances, withdrawals, and signed workflow
  webhooks, authenticated with publishable API keys, alongside JS/React/React Native SDKs and a published Claude Code integration
  skill.
url: https://raw.githubusercontent.com/api-evangelist/halliday/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: 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://halliday.xyz/opengraph-image
x-type: company
x-source: vc-portfolio
x-backed-by:
- a16z
x-tier: profiled
x-tier-reason: enriched-from-portfolio-lead
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-19'
tags:
- Company
- Payments
- Cryptocurrency
- Blockchain
- Web3
- Onramp
- Swaps
- DeFi
- Agentic Workflows
- Fintech
tags_raw:
- Company
- Payments
- Cryptocurrency
- Blockchain
- Web3
- Onramp
- Swaps
- DeFi
- Agentic Workflows
- Fintech
apis:
- aid: halliday:halliday-assets-api
  name: Halliday Assets API
  description: Asset information, discovery, and supported asset pairs
  humanURL: https://docs.halliday.xyz
  baseURL: https://v2.prod.halliday.xyz
  tags:
  - Assets
  properties:
  - type: OpenAPI
    url: openapi/halliday-assets-api-openapi.yml
  - type: Documentation
    url: https://docs.halliday.xyz
  - type: APIReference
    url: https://docs.halliday.xyz/pages/halliday-api-docs.md
  - type: GettingStarted
    url: https://docs.halliday.xyz/pages/api-quickstart.md
- aid: halliday:halliday-chains-api
  name: Halliday Chains API
  description: Blockchain network information and configuration
  humanURL: https://docs.halliday.xyz
  baseURL: https://v2.prod.halliday.xyz
  tags:
  - Chains
  properties:
  - type: OpenAPI
    url: openapi/halliday-chains-api-openapi.yml
  - type: Documentation
    url: https://docs.halliday.xyz
  - type: APIReference
    url: https://docs.halliday.xyz/pages/halliday-api-docs.md
  - type: GettingStarted
    url: https://docs.halliday.xyz/pages/api-quickstart.md
- aid: halliday:halliday-payments-api
  name: Halliday Payments API
  description: Core payment operations including quotes, confirmation, and status tracking
  humanURL: https://docs.halliday.xyz
  baseURL: https://v2.prod.halliday.xyz
  tags:
  - Payments
  properties:
  - type: OpenAPI
    url: openapi/halliday-payments-api-openapi.yml
  - type: Documentation
    url: https://docs.halliday.xyz
  - type: APIReference
    url: https://docs.halliday.xyz/pages/halliday-api-docs.md
  - type: GettingStarted
    url: https://docs.halliday.xyz/pages/api-quickstart.md
- aid: halliday:halliday-webhooks-api
  name: Halliday Webhooks API
  description: 'Register HTTPS endpoints to receive signed notifications when a workflow reaches a terminal

    state, instead of polling for status. You subscribe to one or more event types per webhook.


    | Event type | Fires when a workflow''s status becomes |

    | --- | --- |

    | `WORKFLOW_COMPLETED` | `COMPLETE` |

    | `WORKFLOW_FAILED` | `FAILED` |


    All management endpoints live under `/orgs/webhooks` and authenticate with a secret API key

    (passed as a bearer token) that has webhook access. Publishable keys cannot manage webhooks.


    **Integration checklist**


    - Receiver is a public HTTPS endpoint (no private IPs).

    - Save the `signing_secret` when you create the webhook — it is shown only once.

    - Verify `X-Halliday-Signature` against the raw body, accepting any of its comma-separated signatures.

    - Respond `2xx` quickly and do the real work afterward.

    - Skip deliveries whose `id` you have already handled.'
  humanURL: https://docs.halliday.xyz
  baseURL: https://v2.prod.halliday.xyz
  tags:
  - Webhook
  tags_raw:
  - Webhooks
  properties:
  - type: OpenAPI
    url: openapi/halliday-webhooks-api-openapi.yml
  - type: Documentation
    url: https://docs.halliday.xyz
  - type: APIReference
    url: https://docs.halliday.xyz/pages/halliday-api-docs.md
  - type: GettingStarted
    url: https://docs.halliday.xyz/pages/api-quickstart.md
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: OpenAPI
  url: openapi/_original/halliday-openapi-original.yml
- type: DeveloperPortal
  url: https://docs.halliday.xyz
- type: Documentation
  url: https://docs.halliday.xyz
- type: APIReference
  url: https://docs.halliday.xyz/pages/halliday-api-docs.md
- type: GettingStarted
  url: https://docs.halliday.xyz/pages/api-quickstart.md
- type: Support
  url: https://halliday.xyz/contact
- type: Blog
  url: https://blog.halliday.xyz
- type: GitHubOrganization
  url: https://github.com/HallidayInc
- type: SignUp
  url: https://dashboard.halliday.xyz/
- type: TermsOfService
  url: https://halliday.xyz/legal/terms-of-use
- type: PrivacyPolicy
  url: https://halliday.xyz/legal/privacy-policy
- type: Sandbox
  url: https://demo.halliday.xyz/
- type: Compliance
  url: https://docs.halliday.xyz/pages/compliance-security.md
- type: Authentication
  url: authentication/halliday-authentication.yml
- type: AgenticAccess
  url: agentic-access/halliday-agentic-access.yml
- type: DomainSecurity
  url: security/halliday-domain-security.yml
- type: Packages
  url: packages/halliday-packages.yml
- type: SDKs
  url: packages/halliday-packages.yml
- type: MCPServer
  url: mcp/halliday-mcp.yml
- type: LLMsTxt
  url: llms/halliday-llms.txt
- type: Overlay
  url: overlays/halliday-openapi-overlay.yaml
- type: Conformance
  url: conformance/halliday-conformance.yml
- type: ErrorCatalog
  url: errors/halliday-problem-types.yml
- type: Lifecycle
  url: lifecycle/halliday-lifecycle.yml
- type: Conventions
  url: conventions/halliday-conventions.yml
- type: Components
  url: components/halliday-components.yml
- type: DataModel
  url: data-model/halliday-data-model.yml
- type: Webhooks
  url: asyncapi/halliday-webhooks.yml
- type: AgentSkill
  url: skills/_index.yml
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence

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Halliday

Kin Score

APIs 4

Halliday Assets API

Halliday Chains API

Halliday Payments API

Halliday Webhooks API

Open Collections 5

API Collection

Halliday API V2 Assets API

Halliday API V2 Assets Chains API

Halliday API V2 Assets Payments API

Halliday API V2 Assets Webhooks API

MCP Servers 1

Halliday MCP Server

Event Specifications 1

Halliday Webhooks

Security Posture 2

Halliday Authentication

Halliday Domain Security

Agentic Access 1

Halliday Agentic Access

Resources