Engineering · TRUEFIX LABS

Reconciling Orders, Fills and Positions in Trading Systems

Why production trading systems combine WebSocket events, REST snapshots, trade history, balances, and periodic reconciliation.

Short answer. Reliable reconciliation combines WebSocket events for low-latency updates with REST snapshots and periodic comparison. Use open orders, order history, trade history, positions, balances, and account equity to detect missed events, duplicate events, position drift, and unknown execution results.

Required views

Open orders
Order history
Trade or fill history
Positions
Balances and account equity

Reconciliation loop

WebSocket events
      + REST snapshot
      + periodic reconciliation
      → compare → classify drift → recover → record evidence

Classify differences as expected latency, missing event, duplicate event, provider correction, local bug, or unresolved ambiguity.

Position calculation

Calculate from fills and provider position snapshots, including fees, settlement currency, contract multiplier, realized and unrealized P&L, transfers, and corporate actions where relevant. Do not assume every venue reports the same sign or quantity convention.

Recovery policy

Pause affected execution when drift is material or identity is ambiguous. A reconciliation result should include the snapshot timestamp, source, comparison revision, and operator action.

Sources

Last verified: 2026-09-28. Provider capabilities can change by region, account, product, environment, and entitlement; verify the linked official documentation before production use.

Last updated: 2026-09-28