MQL4
MetaQuotes Language 4 — the legacy procedural language for building Expert Advisors and indicators on MetaTrader 4.
MQL4 is procedural, C-syntax, and tightly bound to MT4's single-instrument backtester. It still has a large installed base — most retail forex brokers default new clients to MT4 — so MQL4 EAs continue to be commissioned even in 2026. MT5's MQL5 is a superset; many MQL4 projects can be ported with limited rewrite if the strategy fits MT5's netting/hedging model. Viprasol delivers both new MQL4 builds and MQL4→MQL5 migrations.
Related terms
MetaQuotes Language 5 — the object-oriented programming language used to build Expert Advisors, indicators, and scripts on MetaTrader 5.
A trading bot that runs inside MetaTrader 4 or 5 and executes orders automatically based on coded rules.
Legacy MetaQuotes terminal still used by most retail forex brokers in 2026; runs MQL4 EAs.
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