Apex Protocol – An open MCP-based standard for AI agent trading

v0.1.0-alpha

APEX defines how AI agents communicate with brokers, exchanges, dealers, and other execution venues. One protocol. Realtime state. Autonomous safety. Multi-asset by design.

FIX Protocol connected electronic trading. APEX connects agentic trading.

Protocol Specification

19 mandatory tools across five domains — session, account, orders, market data, and risk — plus a realtime resource model with live state, notifications, and production capability profiles.

Read the spec

Instrument Taxonomy

A universal instrument identifier system. APEX:FX:EURUSD means the same thing at every broker. No more per-broker symbol mapping. One ID scheme for every tradeable instrument.

See the ID format

Conformance Tests

167 executable conformance checks across 4 reference implementations validating protocol conformance — from basic tool smoke tests to transport resilience, schema validation, and production readiness.

View the test suite

AI Agent

APEX Protocol (MCP over HTTP/SSE)

Broker MCP Server

Tools for actions. Resources for live state. Notifications for change. The broker implements it. The agent speaks it. No hub. No routing. No middleman.

For Brokers

Implement once. Every agent connects.

Build an APEX alpha-compatible MCP server and become accessible to agent integrations through a shared protocol surface — without bespoke integrations for each one.

• Reference implementations in TypeScript, Rust, Go, and Java
• HTTP/SSE transport with session replay and notification delivery
• 167-check conformance harness across stdio and transport
• Canonical instrument IDs across all asset classes
• Production profiles: Realtime and Autonomous capability claims

Broker integration guide

For Agent Developers

Write once. Trade on any broker.

Use canonical instrument IDs and a unified tool vocabulary. Your agent code targets a shared protocol surface rather than per-provider APIs. Switch providers with far less custom integration work.

• Canonical instrument IDs: APEX:FX:EURUSD
• Realtime state: subscribe to quotes, candles, positions, risk
• Event-driven notifications: fills, rejections, candle closes, kill switch
• Deterministic safety: halt on stale data, broken sequences, risk limits
• Open spec, free to implement: CC-BY 4.0

Agent quickstart

Core

Layer 1 — Mandatory Baseline

Session, account, orders, market data, risk

v0.1-alpha

Production

Realtime & Autonomous Profiles

Transport, resources, notifications, safety controls

v0.1-alpha

Profile

FX

Spot FX, CFD FX, rollovers, currency exposure

v0.1-alpha

Profile

CFD

Equities, indices, commodities, corporate actions

v0.1-alpha

Profile

Crypto

Spot, perpetuals, funding rates, margin modes

v0.1-alpha

Profile

Derivatives

Listed options, futures, greeks

planned

Profile

Fixed Income

Bonds, yield, duration

planned

apex.session.* Authentication, capabilities, heartbeat*

apex.account.* Balances, positions, orders, history*

apex.order.* Place, modify, cancel, status*

apex.market.* Quotes, snapshots, search, instrument details*

apex.risk.* Pre-trade checks, account limits*

Live State Resources

Quotes, candles, positions, orders, risk, and derived features exposed as MCP resources with freshness metadata and monotonic sequencing. Subscribe once, stay current.

Structured Notifications

Seven mandatory notification types — order fills, partial fills, rejections, candle closes, kill switch, gap fill, and replay failure — each with a typed envelope carrying sequence, timestamp, and payload.

HTTP/SSE Transport

Streamable HTTP on a single /mcp endpoint. Session management via Mcp-Session-Id. SSE delivery with monotonic event IDs and Last-Event-ID reconnect.

Session Replay

Acknowledgment-driven event log replays execution-critical events on reconnect. Ephemeral market data collapsed into gap fill markers. Agent controls retention via apex.session.acknowledge. Storage is implementation choice — memory, file, or durable queue.

Autonomous Safety

Kill switch, position limits, daily loss caps, stale-data rejection, and sequence-gap detection. The runtime halts autonomy before the model is asked to decide — not after.

Production Profiles

Two capability claims beyond the core baseline: Production Realtime for live trading and Production Autonomous for agent-driven execution with full safety controls.

Open standard. Vendor-neutral. Community-governed.

The APEX Protocol specification is licensed CC-BY 4.0. Reference implementations are Apache 2.0. Governance is through the Technical Advisory Committee with an open RFC process. Agent developers never pay to use the protocol.