Checklist · Liquidity and Market Data
Symbol Mapping Between Platform and Liquidity Feed
Map platform and liquidity symbols using contract, currency, quantity and precision fields, with a worked mismatch example and acceptance checks.
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Published by FxTrusts, a supplier of brokerage and prop firm technology. Prepared with AI-assisted research and drafting; reviewed against the cited public sources. Examples are illustrative. Product links describe our services.
Quick answer
Symbol mapping connects equivalent instrument records across systems. Match economic and technical fields, not only ticker text. The mapping should identify source and destination symbols, currencies, contract size, quantity units, price grid, sessions and effective configuration version.
Start with instrument identity
A familiar symbol label can describe different contracts on different systems. Suffixes can identify account groups, execution routes or separate products. Record stable internal and external identifiers and identify the underlying instrument or contract. For expiring products, maturity matters; for CFDs, the provider’s specification matters. A mapping that removes every suffix mechanically can route an order to a superficially similar but economically different instrument.
Normalize quantity and price independently
One API can express quantity in base-currency units while another uses lots. OANDA’s instrument fields and MQL5 symbol properties illustrate separate unit, precision and minimum-size conventions. A correct quantity conversion does not establish a correct price conversion. Preserve pip location, display precision, tick size and calculation mode as distinct fields. Validate the smallest, typical and largest supported order rather than checking only one convenient size.
Include operational constraints in the mapping
Trading sessions, holidays, order types, filling modes, minimum distances and account eligibility can differ even when the price stream appears equivalent. Record who owns those differences and whether the mapping rejects unsupported requests or transforms them under an approved policy. A transformation should not silently alter a customer’s economic instruction. Where conversion or rounding changes quantity, obtain the relevant authorization and preserve the original request.
Version and test every change
A new contract multiplier or replaced provider symbol can invalidate an old mapping without changing its human-readable name. Keep effective dates, approver, source specifications and rollback information. Test market data, order submission, execution reports and position reconciliation as a full round trip. Historical trades should retain the mapping version that applied when they occurred, so a later export does not reinterpret past quantities using today’s settings.
An illustrative units-to-lots mapping
Assume source X expresses EUR/USD quantity as EUR units and destination Y defines one lot as 100,000 EUR with a 0.01-lot step. A 12,000-unit request converts to 0.12 lots and is valid under that declared grid. A 12,500-unit request converts to 0.125 lots and fails it. The mapping must not silently round away 500 EUR of requested quantity. These are hypothetical configurations.
| Field | Source X | Destination Y |
|---|---|---|
| Quantity basis | EUR units | Lots of 100,000 EUR |
| Example quantity | 12,000 units | 0.12 lots |
| Quantity step | 1 unit assumed | 0.01 lot assumed |
| Mismatch case | 12,500 units | 0.125 lots: invalid step |
| Required decision | Preserve original instruction | Reject or follow an explicitly authorized policy |
Implementation checklist
- Compare contract identity, currencies and maturity where relevant.
- Map quantity units separately from price precision and tick size.
- Test sessions, permissions and supported instruction combinations.
- Version the mapping and retain round-trip reconciliation evidence.
Sources
These documents support the reference. Check the original publication for current requirements and the limits of its scope.
- MQL5 symbol propertieswww.mql5.com
- OANDA v20 instrument definitionsdeveloper.oanda.com
- MetaTrader 5 symbol specificationswww.metatrader5.com
Continue with the broader guides
Connect this reference to platform selection and the wider operating workflow.