Sfox

sFOX is a unified crypto prime brokerage and infrastructure platform for professional and institutional investors — asset managers, hedge funds, family offices, and financial institutions. It aggregates liquidity from 30+ providers across 80+ markets for smart-routed best execution, and combines that with bankruptcy-remote custody (sFOX SAFE, via SAFE Trust Company), staking, credit, and post-trade settlement in one platform. sFOX exposes a REST API, a WebSocket streaming API, and a FIX API for trading, account management, RFQ, transfers, custody, staking, market data, and reporting; a separate white-label "Connect" API covers end-user onboarding, KYC/KYB, bank linking (Plaid/Dwolla), payments, withdrawals, and SSO for businesses building crypto products.

Sfox publishes 2 APIs on the APIs.io network: REST API and WebSocket API. Tagged areas include Company, Cryptocurrency, Prime Brokerage, Trading, and Digital Asset Custody.

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

Sfox’s developer surface includes documentation, API reference, getting-started guide, engineering blog, support, signup flow, authentication, and 18 more developer resources.

🌐 Visit website 📡 Source on GitHub

44.7/100 developing ▬ flat Agent 32/100 agent aware Full breakdown ↓
scored 2026-08-20 · rubric v0.12.0

AccessSelf serve

3 APIs 1 MCP Servers

CompanyCryptocurrencyPrime BrokerageTradingDigital Asset CustodyLiquidityStakingInstitutionalFinancial-ServicesMarket DataWebSocketFIX

Kin Score

Kin Score How this is scored →
scored 2026-08-20 · rubric v0.12.0

Composite quality — 44.7/100 · developing

Contract Quality 10.4 / 21

Developer Ergonomics 8.1 / 17

Access Clarity 4.7 / 17

Operational Transparency 4.9 / 11

Contract Governance 0.5 / 10

Discoverability 6.9 / 9

Regulatory Posture 8.3 / 15

Agent readiness — 32/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 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 0 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 6 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 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 Securities & Market Data 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/sfox: 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 3

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.

Sfox MCP Server

MCP SERVER

Rate Limits 1

Documented rate limits and quota policies.

Get Started 5

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

SignUp

SignUp

Login

Sandbox

Sandbox

Documentation 3

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

AsyncAPI

AsyncAPI

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

MCPServer

MCPServer

WellKnown

WellKnown

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

ErrorCatalog

Lifecycle

Conventions

Conformance

DataModel

Webhooks

Access & Security 2

Authentication, authorization, and security posture

Authentication

Authentication

DomainSecurity

DomainSecurity

Operate 3

Status, limits, changes, and where to get help

Support

Support

RateLimits

RateLimits

ChangeLog

ChangeLog

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 1

The organization behind the API

Blog

Blog

Source (apis.yml)

aid: sfox
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://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/sfox.png
name: Sfox
description: sFOX is a unified crypto prime brokerage and infrastructure platform for professional and institutional investors
  — asset managers, hedge funds, family offices, and financial institutions. It aggregates liquidity from 30+ providers across
  80+ markets for smart-routed best execution, and combines that with bankruptcy-remote custody (sFOX SAFE, via SAFE Trust
  Company), staking, credit, and post-trade settlement in one platform. sFOX exposes a REST API, a WebSocket streaming API,
  and a FIX API for trading, account management, RFQ, transfers, custody, staking, market data, and reporting; a separate
  white-label "Connect" API covers end-user onboarding, KYC/KYB, bank linking (Plaid/Dwolla), payments, withdrawals, and SSO
  for businesses building crypto products.
url: https://raw.githubusercontent.com/api-evangelist/sfox/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- y-combinator
x-tier: stub
x-tier-reason: portfolio-lead
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-21'
tags:
- Company
- Cryptocurrency
- Prime Brokerage
- Trading
- Digital Asset Custody
- Liquidity
- Staking
- Institutional
- Financial-Services
- Market Data
- WebSocket
- FIX
tags_raw:
- Company
- Cryptocurrency
- Prime Brokerage
- Trading
- Digital Asset Custody
- Liquidity
- Staking
- Institutional
- Financial Services
- Market Data
- WebSocket
- FIX
apis:
- name: sFOX REST API
  description: REST API for trading, order management, RFQ, account balances and transactions, transfers/deposits/withdrawals,
    custody (sFOX SAFE), staking, post-trade settlement, market data, and reporting. Bearer-token API-key auth over HTTPS.
  humanURL: https://docs.sfox.com/introduction/getting-started
  baseURL: https://api.sfox.com
  properties:
  - type: Documentation
    url: https://docs.sfox.com/
  - type: APIReference
    url: https://docs.sfox.com/rest-api/rest-endpoints
  - type: Authentication
    url: authentication/sfox-authentication.yml
  - type: LLMsTxt
    url: llms/sfox-llms.txt
  - type: OpenAPI
    url: https://docs.sfox.com/rest-api/rest-endpoints
- name: sFOX WebSocket API
  description: Real-time streaming API for market data (order book, trades, ticker) and private account data (open orders,
    trades, balances, post-trade settlement). Authenticate then subscribe to feeds.
  humanURL: https://docs.sfox.com/websocket-api/introduction
  baseURL: https://ws.sfox.com
  properties:
  - type: Documentation
    url: https://docs.sfox.com/websocket-api/introduction
  - type: AsyncAPI
    url: asyncapi/sfox-websocket-asyncapi.yml
- name: sFOX Connect API
  description: 'White-label REST + WebSocket API for businesses: end-user management, KYC/KYB and Enhanced Due Diligence,
    bank-account linking (Plaid), ACH (Dwolla) and wire payments, withdrawals, transfers, monetization settings, and SSO (SAML).'
  humanURL: https://docs.sfox.com/connect/introduction/welcome
  baseURL: https://api.sfox.com
  properties:
  - type: Documentation
    url: https://docs.sfox.com/connect/introduction/welcome
  - type: ChangeLog
    url: changelog/sfox-changelog.yml
common:
- type: DeveloperPortal
  url: https://www.sfox.com/api/
- type: Documentation
  url: https://docs.sfox.com/
- type: APIReference
  url: https://docs.sfox.com/rest-api/rest-endpoints
- type: GettingStarted
  url: https://docs.sfox.com/introduction/getting-started
- type: Blog
  url: https://www.sfox.com/news/
- type: Support
  url: https://www.sfox.com/contact-us/
- type: SignUp
  url: https://trade.sfox.com/signup
- type: Login
  url: https://trade.sfox.com/login
- type: TermsOfService
  url: https://www.sfox.com/terms/
- type: PrivacyPolicy
  url: https://www.sfox.com/privacy/
- type: Authentication
  url: authentication/sfox-authentication.yml
- type: LLMsTxt
  url: llms/sfox-llms.txt
- type: MCPServer
  url: mcp/sfox-mcp.yml
- type: WellKnown
  url: well-known/sfox-well-known.yml
- type: ErrorCatalog
  url: errors/sfox-problem-types.yml
- type: Lifecycle
  url: lifecycle/sfox-lifecycle.yml
- type: RateLimits
  url: rate-limits/sfox-rate-limits.yml
- type: Conventions
  url: conventions/sfox-conventions.yml
- type: Conformance
  url: conformance/sfox-conformance.yml
- type: DataModel
  url: data-model/sfox-data-model.yml
- type: Sandbox
  url: sandbox/sfox-sandbox.yml
- type: DomainSecurity
  url: security/sfox-domain-security.yml
- type: ChangeLog
  url: changelog/sfox-changelog.yml
- type: AsyncAPI
  url: asyncapi/sfox-websocket-asyncapi.yml
- type: Webhooks
  url: asyncapi/sfox-websocket-asyncapi.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-07-21'
  status: enriched
  artifacts_added: 14
  pass: local-v1

Sfox

Kin Score

APIs 3

sFOX REST API

sFOX WebSocket API

sFOX Connect API

MCP Servers 1

Sfox MCP Server

Rate Limits 1

Sfox Rate Limits

Event Specifications 1