OneChronos

OneChronos operates AI-powered "Smart Market" alternative trading systems that match institutional orders using Nobel Prize-winning combinatorial auction techniques and mathematical optimization rather than traditional price-time priority matching. Operated by OneChronos Markets LLC, a broker-dealer subsidiary of OCX Group Inc., the venue runs point-in-time periodic auctions roughly ten times per second across US equities (a dark ATS launched in 2022), spot foreign exchange, and UK/EU equities multilateral trading facilities. Subscribers connect and submit orders electronically over a modern variant of the FIX 4.2 protocol, with "expressive bidding" that lets traders encode custom constraints, spreads, pairs, portfolio and hedging strategies into each auction.

OneChronos publishes 3 APIs on the APIs.io network. Tagged areas include Company, Financial-Services, Capital Markets, Trading, and Equities.

OneChronos’ developer surface includes documentation, API reference, getting-started guide, support, engineering blog, pricing, and 9 more developer resources.

🌐 Visit website 📡 Source on GitHub

21.5/100 emerging ▬ flat Agent 0/100 human only saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

3 APIs

Company Financial-Services Capital Markets Trading Equities Alternative Trading System FIX Protocol Foreign Exchange Institutional Investing Market Infrastructure

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 21.5/100 · emerging

Contract Quality 0.0 / 21

Developer Ergonomics 7.7 / 17

Access Clarity 3.6 / 17

Operational Transparency 0.3 / 11

Contract Governance 1.9 / 10

Discoverability 6.1 / 9

Regulatory Posture 3.8 / 15

Agent readiness — 0/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 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

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 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.

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

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/onechronos: 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 3

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

OneChronos US Equities ATS (FIX 4.2)

Order entry and execution for the OneChronos US equities dark ATS over a modern variant of the FIX 4.2 protocol. Standard and Target orders, and Expressive Bids, are submitted e...

OneChronos FX Smart Market (FIX 4.2)

Order entry for the OneChronos spot foreign exchange Smart Market over the FIX 4.2 protocol variant, applying the same combinatorial-auction matching to global FX.

OneChronos European Equities MTF (FIX 4.2)

Order entry for the OneChronos UK and EU equities multilateral trading facilities over the FIX 4.2 protocol variant.

Security Posture 1

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

Onechronos Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 2

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

WellKnown

WellKnown

LLMsTxt

LLMsTxt

Design & Contract 1

Pagination, idempotency, versioning, errors, and events

Conformance

Conformance

Build 2

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Packages

Packages

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 2

Pricing, plans, and the legal terms of use

Pricing

Pricing

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Source (apis.yml)

aid: onechronos
name: OneChronos
description: OneChronos operates AI-powered "Smart Market" alternative trading systems that match institutional orders using
  Nobel Prize-winning combinatorial auction techniques and mathematical optimization rather than traditional price-time priority
  matching. Operated by OneChronos Markets LLC, a broker-dealer subsidiary of OCX Group Inc., the venue runs point-in-time
  periodic auctions roughly ten times per second across US equities (a dark ATS launched in 2022), spot foreign exchange,
  and UK/EU equities multilateral trading facilities. Subscribers connect and submit orders electronically over a modern variant
  of the FIX 4.2 protocol, with "expressive bidding" that lets traders encode custom constraints, spreads, pairs, portfolio
  and hedging strategies into each auction.
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: false
  label: Hosted service · you call their endpoint
  confidence: medium
  source:
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source: []
  generated: '2026-07-22'
  method: derived
image: https://www.onechronos.com/og-image.png
url: https://raw.githubusercontent.com/api-evangelist/onechronos/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- dcvc
x-tier: profiled
x-tier-reason: enriched-from-portfolio-lead
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-20'
tags:
- Company
- Financial-Services
- Capital Markets
- Trading
- Equities
- Alternative Trading System
- FIX Protocol
- Foreign Exchange
- Institutional Investing
- Market Infrastructure
tags_raw:
- Company
- Financial Services
- Capital Markets
- Trading
- Equities
- Alternative Trading System
- FIX Protocol
- Foreign Exchange
- Institutional Investing
- Market Infrastructure
apis:
- name: OneChronos US Equities ATS (FIX 4.2)
  description: Order entry and execution for the OneChronos US equities dark ATS over a modern variant of the FIX 4.2 protocol.
    Standard and Target orders, and Expressive Bids, are submitted electronically via FIX over TCP/IP; the ATS hosts periodic
    auctions approximately ten times per second.
  humanURL: https://www.onechronos.com/documentation/fix/fix-42/us-equities/
  properties:
  - type: Documentation
    url: https://www.onechronos.com/documentation/user-manual/us-equities/
  - type: APIReference
    url: https://www.onechronos.com/documentation/fix/fix-42/us-equities/
- name: OneChronos FX Smart Market (FIX 4.2)
  description: Order entry for the OneChronos spot foreign exchange Smart Market over the FIX 4.2 protocol variant, applying
    the same combinatorial-auction matching to global FX.
  humanURL: https://www.onechronos.com/documentation/fix/fix-42/fx/
  properties:
  - type: Documentation
    url: https://www.onechronos.com/documentation/user-manual/fx/
  - type: APIReference
    url: https://www.onechronos.com/documentation/fix/fix-42/fx/
- name: OneChronos European Equities MTF (FIX 4.2)
  description: Order entry for the OneChronos UK and EU equities multilateral trading facilities over the FIX 4.2 protocol
    variant.
  humanURL: https://www.onechronos.com/documentation/fix/fix-42/european-equities/
  properties:
  - type: APIReference
    url: https://www.onechronos.com/documentation/fix/fix-42/european-equities/
common:
- type: Website
  url: https://www.onechronos.com/
- type: DeveloperPortal
  url: https://www.onechronos.com/documentation/fix/primer/
- type: Documentation
  url: https://www.onechronos.com/documentation/user-manual/us-equities/
- type: APIReference
  url: https://www.onechronos.com/documentation/fix/fix-42/
- type: GettingStarted
  url: https://www.onechronos.com/documentation/fix/primer/
- type: Support
  url: https://www.onechronos.com/contact/
- type: Blog
  url: https://www.onechronos.com/insights/
- type: GitHubOrganization
  url: https://github.com/onechronos
- type: Pricing
  url: https://www.onechronos.com/products/us-equities/fees/
- type: PrivacyPolicy
  url: https://www.onechronos.com/legal/privacy-policy/
- type: Packages
  url: packages/onechronos-packages.yml
- type: WellKnown
  url: well-known/onechronos-well-known.yml
- type: Conformance
  url: conformance/onechronos-conformance.yml
- type: DomainSecurity
  url: security/onechronos-domain-security.yml
- type: LLMsTxt
  url: llms/onechronos-llms.txt
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-07-20'
  status: enriched
  artifacts_added: 5
  pass: local-v1

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