A5X

A5X S.A. is a next-generation derivatives and futures exchange and clearing house being built for the Brazilian market, founded in 2023 in Sao Paulo by former XP executives Carlos Ferreira Filho and Karel Luketic together with Nilson Monteiro (Ideal) and Julian Chediak. It is an asset-light, technology-first venue running on London Stock Exchange Group trading, clearing and market surveillance technology, and it has raised R$385 million (about USD 72.6 million) from investors including IMC Trading, Jump Trading Group, Optiver, XTX Markets and ABN AMRO Clearing. Its listed, financially settled contract set covers stock index futures and options (local and offshore), single stock futures and options, currency futures and options, local interest rate futures and options, and cryptocurrency futures, with European-style options exercised automatically at expiry. For integrators, A5X publishes a technical developer portal covering connectivity (site-to-site VPN, LAN-to-LAN, cross connect at Equinix SP3, AWS Direct Connect), order entry, market data, drop copy and post-trade settlement, allocation, positioning and risk interfaces over FIX and binary protocols. The portal requires a login, so those specifications are not publicly readable.

A5X publishes 1 API on the APIs.io network. Tagged areas include Company, Financial Services, Capital Markets, Stock Exchange, and Derivatives.

A5X’s developer surface includes engineering blog, support, and 12 more developer resources.

🌐 Visit website 📡 Source on GitHub
18.4/100 emerging ▬ flat Agent 3/100 human only Front door AI 1/6 silent Full breakdown ↓
scored 2026-09-25 · rubric v0.23.0
1 APIs
CompanyFinancial ServicesCapital MarketsStock ExchangeDerivativesFuturesTradingMarket DataClearingFIX ProtocolBrazil

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-09-25 · rubric v0.23.0
Composite quality — 18.4/100 · emerging
Contract Quality 0.0 / 21
Developer Ergonomics 4.5 / 17
Access Clarity 3.6 / 17
Operational Transparency 0.0 / 11
Contract Governance 1.9 / 10
Discoverability 5.5 / 9
Regulatory Posture 3.5 / 15
Agent readiness — 3/100 · 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 7 / 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/a5x: 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 1

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

A5X Technical Interfaces

The trading, market data and post-trade interfaces A5X exposes to exchange participants — order entry and drop copy over FIX, a binary market data feed, and post-trade capture, ...

Pricing Plans 1

Published pricing tiers and plan structures.

A5X Plans Pricing

0 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

A5X Rate Limits

0 limits

RATE LIMITS

Security Posture 1

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

A5X Domain Security

TLSv1.3 · DMARC

SECURITY

Resources

Get Started 1

Portal, sign-up, and the first successful call

DeveloperPortal
DeveloperPortal

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt
LLMsTxt

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

Lifecycle
Lifecycle
 Conformance
Conformance

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity
DomainSecurity

Operate 2

Status, limits, changes, and where to get help

Support
Support
 RateLimits
RateLimits

Commercial 3

Pricing, plans, and the legal terms of use

TermsOfService
TermsOfService
 PrivacyPolicy
PrivacyPolicy
 Plans
Plans

Company 4

The organization behind the API

Website
Website
 Blog
Blog
 BlogRSS
BlogRSS
 LinkedIn
LinkedIn

Source (apis.yml)

apis.yml Raw ↑ 
aid: a5x
name: A5X
description: A5X S.A. is a next-generation derivatives and futures exchange and clearing house being built for the Brazilian
  market, founded in 2023 in Sao Paulo by former XP executives Carlos Ferreira Filho and Karel Luketic together with Nilson
  Monteiro (Ideal) and Julian Chediak. It is an asset-light, technology-first venue running on London Stock Exchange Group
  trading, clearing and market surveillance technology, and it has raised R$385 million (about USD 72.6 million) from investors
  including IMC Trading, Jump Trading Group, Optiver, XTX Markets and ABN AMRO Clearing. Its listed, financially settled contract
  set covers stock index futures and options (local and offshore), single stock futures and options, currency futures and
  options, local interest rate futures and options, and cryptocurrency futures, with European-style options exercised automatically
  at expiry. For integrators, A5X publishes a technical developer portal covering connectivity (site-to-site VPN, LAN-to-LAN,
  cross connect at Equinix SP3, AWS Direct Connect), order entry, market data, drop copy and post-trade settlement, allocation,
  positioning and risk interfaces over FIX and binary protocols. The portal requires a login, so those specifications are
  not publicly readable.
image: https://a5x.com.br/wp-content/uploads/2025/07/A5X-Logo-Vetorizado-Azul-1.png
url: https://raw.githubusercontent.com/api-evangelist/a5x/refs/heads/main/apis.yml
x-type: company
x-source: harvest:secondary-market
specificationVersion: '0.20'
created: '2026-09-05'
modified: '2026-09-05'
tags:
- Company
- Financial Services
- Capital Markets
- Stock Exchange
- Derivatives
- Futures
- Trading
- Market Data
- Clearing
- FIX Protocol
- Brazil
tags_raw:
- Company
- Financial Services
- Capital Markets
- Stock Exchange
- Derivatives
- Futures
- Trading
- Market Data
- Clearing
- FIX Protocol
- Brazil
- Financial-Services
apis:
- aid: a5x:a5x-technical-interfaces
  name: A5X Technical Interfaces
  description: The trading, market data and post-trade interfaces A5X exposes to exchange participants — order entry and drop
    copy over FIX, a binary market data feed, and post-trade capture, allocation, positioning and risk messaging. Message
    catalogs, session recovery rules, order identifier formats and field limits are documented in the A5X Dev Portal (Portal
    Tecnico), which requires credentials; no public machine-readable contract (OpenAPI, AsyncAPI, GraphQL SDL or downloadable
    FIX dictionary) is published at an anonymous URL, and the exchange had not begun production operations as of this profile.
  humanURL: https://portal-tecnico.a5x.com.br/login
  image: https://a5x.com.br/wp-content/uploads/2025/07/A5X-Logo-Vetorizado-Azul-1.png
  tags:
  - Trading
  - Market Data
  - Post-Trade
  - FIX Protocol
  - Derivatives
  properties:
  - type: DeveloperPortal
    url: https://portal-tecnico.a5x.com.br/login
  - type: Documentation
    url: https://a5x.com.br/en/blog/a5x-en/a5x-dev-portal-provides-specifications-for-developers/
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: DomainSecurity
  url: security/a5x-domain-security.yml
- type: Website
  url: https://a5x.com.br/en/
- type: DeveloperPortal
  url: https://portal-tecnico.a5x.com.br/login
- type: Blog
  url: https://a5x.com.br/en/blog/
- type: BlogRSS
  url: https://a5x.com.br/en/feed/
- type: Support
  url: https://a5x.com.br/en/contact-us/
- type: TermsOfService
  url: https://a5x.com.br/en/terms-of-use/
- type: PrivacyPolicy
  url: https://a5x.com.br/en/privacy-policy/
- type: LinkedIn
  url: https://www.linkedin.com/company/a5x
- type: LLMsTxt
  url: llms/a5x-llms.txt
- type: Plans
  url: plans/a5x-plans-pricing.yml
- type: RateLimits
  url: rate-limits/a5x-rate-limits.yml
- type: Lifecycle
  url: lifecycle/a5x-lifecycle.yml
- type: Conformance
  url: conformance/a5x-conformance.yml
x-enrichment:
  date: '2026-09-05'
  status: minimal
  artifacts_added: 7
  pass: local-v3
x-coverage:
  state: gated
  reason: partner-login
  detail: Every A5X technical specification — FIX and binary order entry, market data, drop copy, and the post-trade message
    catalogs — sits inside the Portal Tecnico wiki at portal-tecnico.a5x.com.br, which returns HTTP 403 to every anonymous
    request for a document path while the public /docs/ archive on the marketing site holds only three billing pages whose
    bodies are placeholder text.
  evidence:
  - url: https://portal-tecnico.a5x.com.br/docs
    status: 403
  - url: https://portaldev.a5x.com.br/openapi.json
    status: 403
  - url: https://a5x.com.br/docs/documentacao-sobre-faturamento/
    status: 200
  - url: https://a5x.com.br/.well-known/security.txt
    status: 404
  checked: '2026-09-05'

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