✅ Checking if Symbol Exists

Request: check symbol existence from MT5. Verify if a symbol with a specified name exists (standard or custom).

API Information:

• SDK wrapper: MT5Account.SymbolExistAsync(...) (from NuGet package MetaRPC.MT5)
• gRPC service: mt5_term_api.MarketInfo
• Proto definition: SymbolExist (defined in mt5-term-api-market-info.proto)

RPC

• Service: mt5_term_api.MarketInfo
• Method: SymbolExist(SymbolExistRequest) → SymbolExistReply
• Low‑level client (generated): MarketInfo.SymbolExist(request, headers, deadline, cancellationToken)
• SDK wrapper (your class):

namespace mt5_term_api
{
    public class MT5Account
    {
        public async Task<SymbolExistData> SymbolExistAsync(
            string symbolName,
            DateTime? deadline = null,
            CancellationToken cancellationToken = default);
    }
}

Request message:

SymbolExistRequest { name: string }

Reply message:

SymbolExistReply { data: SymbolExistData } or { error: Error }

---

🔽 Input

Parameter	Type	Required	Description
symbolName	string	✅	Symbol name to check (e.g., "EURUSD", "BTCUSD")
deadline	DateTime?	❌	Absolute per‑call UTC deadline → converted to timeout
cancellationToken	CancellationToken	❌	Cooperative cancel for the call/retry loop

---

⬆️ Output — SymbolExistData

Field	Type	Description
Exists	bool	true if symbol exists (standard or custom), false if not found
IsCustom	bool	true if the detected symbol is a custom symbol, false for standard symbols (see MQL5 Custom Symbols)

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💬 Just the essentials

• What it is. Single RPC checking if a symbol exists and whether it's custom.
• Why you need it. Validate symbol names before trading, check if broker supports a symbol, detect custom symbols.
• Two flags. Exists tells if found, IsCustom tells if it's a custom (synthetic) symbol.

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🎯 Purpose

Use this method when you need to:

• Verify a symbol name before attempting to trade or get quotes.
• Check if your broker supports a specific symbol.
• Detect whether a symbol is standard or custom/synthetic.
• Validate user input (symbol names) in your trading application.
• Handle different symbols gracefully (fail early if symbol doesn't exist).

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🧩 Notes & Tips

• Symbol names are case-sensitive in some brokers (use exact spelling: "EURUSD" not "eurusd").
• If Exists=false, the symbol is not available from your broker.
• If Exists=true and IsCustom=true, the symbol is synthetic/custom - may have different trading rules.
• Use this before SymbolSelectAsync() to avoid errors when adding symbols to Market Watch.
• Fast operation - use short timeout (3-5s).
• Standard symbols: forex pairs, stocks, indices, commodities from broker.
• Custom symbols: user-created synthetic instruments, spreads, custom data feeds.

---

🔗 Usage Examples

1) Check if symbol exists

// Verify EURUSD is available
var result = await acc.SymbolExistAsync(
    "EURUSD",
    deadline: DateTime.UtcNow.AddSeconds(3));

if (result.Exists)
{
    Console.WriteLine("✅ EURUSD exists");
}
else
{
    Console.WriteLine("❌ EURUSD not found");
}

2) Detect custom symbols

// Check if symbol is custom/synthetic
var btc = await acc.SymbolExistAsync("BTCUSD");

Console.WriteLine($"Exists:   {btc.Exists}");
Console.WriteLine($"Custom:   {btc.IsCustom}");

if (btc.Exists && btc.IsCustom)
{
    Console.WriteLine("⚠️ This is a custom/synthetic symbol");
}

3) Validate user input

// Validate symbol before trading
string userSymbol = "GBPJPY"; // from user input

var check = await acc.SymbolExistAsync(userSymbol);

if (!check.Exists)
{
    Console.WriteLine($"❌ Error: Symbol '{userSymbol}' not available");
    return;
}

Console.WriteLine($"✅ Symbol '{userSymbol}' is valid");
// Continue with trading logic...

4) Check multiple symbols

// Verify a list of symbols
var symbols = new[] { "EURUSD", "GBPUSD", "USDJPY", "XAUUSD" };

Console.WriteLine("Checking symbols:");
foreach (var sym in symbols)
{
    var result = await acc.SymbolExistAsync(sym);
    var status = result.Exists ? "✅" : "❌";
    var type = result.IsCustom ? "(custom)" : "(standard)";
    Console.WriteLine($"  {status} {sym,-10} {(result.Exists ? type : "")}");
}

5) Safe symbol selection

// Check existence before adding to Market Watch
var symbolName = "EURUSD";
var exists = await acc.SymbolExistAsync(symbolName);

if (!exists.Exists)
{
    Console.WriteLine($"❌ Cannot add '{symbolName}': symbol doesn't exist");
    return;
}

// Symbol exists - safe to add to Market Watch
var selected = await acc.SymbolSelectAsync(symbolName, select: true);
Console.WriteLine($"✅ '{symbolName}' added to Market Watch");