This repository documents the architecture, correctness guarantees, and verification approach of a production-grade trading backend designed for correctness-critical financial workflows.
The focus of this work is deterministic execution, capital safety, explicit state transitions, and operational recoverability under concurrent load. The implementation is private by design. This repository contains architecture, system flows, invariants, failure analysis, verification artifacts, and security control mappings.
Financial trading systems operate under strict correctness requirements. Errors can result in direct financial loss, regulatory exposure, and loss of trust. Many systems prioritize throughput or implementation convenience and rely on mutable state, optimistic retries, or implicit ordering assumptions that fail under concurrency.
This repository exists to document an alternative approach:
- Deterministic execution with explicit ordering guarantees
- Append-only accounting for funds and reservations
- Atomic enforcement of capital constraints
- Fail-closed behavior under uncertainty
- Tamper-evident auditability
- Independent verification through replay and formal methods
The goal is not to present a feature-complete brokerage, but to demonstrate how correctness-first systems can be designed, reasoned about, and validated in practice.
The documented system models a realistic trading backend, including:
- Order intake and lifecycle management
- Pre-trade capital and margin reservation
- In-memory deterministic matching
- Atomic execution and accounting
- Event-driven propagation using an outbox pattern
- Settlement lifecycle handling
- Corporate action processing
- Recovery and reconciliation through deterministic replay
- Operational kill switches
- Tamper-evident audit logging
The scope intentionally emphasizes correctness, clarity, and verifiability over breadth of features.
This is a documentation and verification repository. It includes:
- System architecture and component boundaries
- End-to-end execution and event flows
- Explicit correctness invariants
- Documented failure modes and race conditions
- Verification methodology including replay and formal specification
- Empirical benchmark results
- Security and audit architecture
- SOC 2 and ISO 27001 control mappings
- Threat modeling and evidence policy
It does not contain application source code.
The implementation represents production-grade intellectual property, including execution logic, concurrency control, and accounting mechanisms.
Publishing full source code would undermine the value of the work without adding meaningful signal for architectural or correctness review. Instead, this repository exposes the design, guarantees, and verification artifacts required to evaluate the system at an engineering and security level.
Selected evidence can be shared in controlled contexts such as interviews, technical deep dives, or due diligence discussions.
The system is built around the following principles:
- Determinism over convenience
- Append-only financial accounting
- Explicit state transitions
- Single authority for execution decisions
- Separation of write-side correctness and read-side materialization
- Fail-closed behavior under partial failure
- Independent verification of derived state
- Operational controls to limit blast radius
These principles are enforced structurally rather than by convention.
Correctness is validated through multiple complementary methods:
- Deterministic replay to reconstruct derived state from authoritative records
- Adversarial concurrency testing to expose race conditions
- Formal specification of the accounting kernel using TLA+
- Mechanical model checking of safety invariants
- Empirical stress testing under concurrent load
Verification artifacts and results are documented in detail within this repository.
This repository is intended for:
- Senior and staff backend engineers
- Distributed systems practitioners
- Fintech and trading infrastructure teams
- Security and platform engineers
- Reviewers evaluating correctness-critical systems
It assumes familiarity with transactional systems, concurrency, and backend architecture.
Each document focuses on a specific aspect of the system:
- ARCHITECTURE.md describes system structure and boundaries
- SYSTEM_FLOWS.md details execution, eventing, settlement, and recovery flows
- INVARIANTS.md defines correctness guarantees
- FAILURE_MODES.md analyzes known failure scenarios
- VERIFICATION.md explains replay, adversarial testing, and formal verification
- BENCHMARKS.md presents empirical performance results
- SECURITY_CONTROLS.md documents implemented security mechanisms
- COMPLIANCE_MAPPING.md maps controls to SOC 2 and ISO 27001
- THREAT_MODEL.md identifies risks and mitigations
- EVIDENCE_POLICY.md defines what artifacts can be shared and how
Documentation only. All rights reserved.