Code migration guide
thinkScript to MQL4 converter
A thinkScript study can become an MQL4 indicator after its declarative series are implemented with callbacks and buffers; a strategy needs a separate Expert Advisor design for real order tickets, risk, and broker errors.
Generate an MQL4 draft, then compile it in MetaEditor and test it in MetaTrader 4.
Conversion map
What changes between thinkorswim and MetaTrader 4
The migration is a model translation. Use this map to decide where the source behavior belongs before writing target syntax.
| Concern | Source model | Target model | Migration decision |
|---|---|---|---|
| Lifecycle | Declarative expressions are evaluated over chart data; studies, strategies, scans, and watchlist columns have different contexts. | Expert Advisors and indicators respond to predefined callbacks such as OnInit, OnTick, and OnCalculate. | Choose when each thinkorswim calculation should run in MetaTrader 4; matching syntax alone does not preserve timing. |
| Market data and history | Definitions and plots form time series and access prior values with bracket indexing or recursive definitions. | Price series use terminal arrays and shift-based access; indicators commonly expose calculated values through buffers. | Recheck bar indexing, warm-up requirements, timeframe requests, and behavior on an unfinished bar. |
| Indicators and chart output | Studies use def, plot, painting, and built-in study functions to render chart analysis. | Custom indicators bind buffers, while built-in indicator functions can return values directly for a requested shift. | Map calculations before recreating plots, labels, colors, and platform-specific drawing objects. |
| Orders and positions | Strategies use AddOrder to add simulated orders to charts; platform conditional orders are a separate workflow. | Classic trade functions such as OrderSend work with order tickets, lots, prices, stops, and a shared order pool. | Define fill timing, sizing, pyramiding or hedging, stops, and position ownership for the target platform. |
| Native validation | Paste into thinkScript Editor, save it as the correct study or strategy, add it to a chart, and inspect plots or the strategy report. | Compile the .mq4 file in MetaEditor, attach it in MetaTrader 4, and test the correct EA or indicator artifact. | Treat generated MQL4 as a draft until it passes the target editor, chart, and backtest workflow. |
Code example
Moving-average cross: thinkScript to MQL4
These fragments show where the same signal starts in each API. They are not complete standalone programs; lifecycle setup, inputs, plots, and order handling still depend on the selected artifact.
def fast = Average(close, 10);
def slow = Average(close, 20);
plot longSignal = fast crosses above slow;double fast0 = iMA(NULL, 0, 10, 0, MODE_SMA, PRICE_CLOSE, 0);
double fast1 = iMA(NULL, 0, 10, 0, MODE_SMA, PRICE_CLOSE, 1);
double slow0 = iMA(NULL, 0, 20, 0, MODE_SMA, PRICE_CLOSE, 0);
double slow1 = iMA(NULL, 0, 20, 0, MODE_SMA, PRICE_CLOSE, 1);
bool longSignal = fast1 <= slow1 && fast0 > slow0;Workflow
A four-step migration path
Keep generation, target-platform validation, and behavior comparison as separate stages.
- 1
Inventory the source behavior
Separate calculations, plots, alerts, orders, external dependencies, and assumptions in a thinkScript study or strategy definition.
- 2
Choose the target artifact
Decide whether the result is an .mq4 Expert Advisor or custom indicator. This choice controls lifecycle methods and available APIs.
- 3
Rewrite through target APIs
Translate state, series, indicators, drawings, and orders into MetaTrader 4 concepts instead of replacing function names.
- 4
Validate behavior natively
Compile the .mq4 file in MetaEditor, attach it in MetaTrader 4, and test the correct EA or indicator artifact.
Manual decisions
Decisions code replacement cannot make
- Choose an MQL4 indicator for chart output or an Expert Advisor for trade execution.
- Add explicit buffer management, warm-up, and per-bar calculation around thinkScript formulas.
- Use AddOrder only as a signal specification when designing MT4 entries, exits, lots, and stops.
Limitations
What the draft cannot prove
- thinkorswim and MetaTrader 4 do not share one execution, data, or order model, so behavior can change even when both versions compile.
- Broker, symbol, session, timezone, history, and fill settings can change signals and backtest results on MetaTrader 4.
- Pineify can generate and revise a MQL4 draft, but the target platform remains the authority for compilation, loading, backtesting, and runtime behavior.
Use cases
When this conversion is useful
- Port a thinkorswim study to an MT4 custom indicator.
- Rebuild a thinkScript strategy as an MQL4 Expert Advisor.
- Add MT4 alerts or execution to a previously chart-only calculation.
FAQ
thinkScript to MQL4 questions
Official references
- thinkScript reference overview
Charles Schwab, checked 2026-08-10
- Creating thinkScript strategies
Charles Schwab, checked 2026-08-10
- MQL4 event handling functions
MetaQuotes, checked 2026-08-10
- MQL4 OrderSend reference
MetaQuotes, checked 2026-08-10
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Browse all convertersBuild the MQL4 draft with its native model in view
Bring the complete source and your artifact, timing, data, and order requirements. Validate the result in MetaTrader 4.