TradingView Pine Script Strategy Alerts Guide: Fire Webhooks to MT5

Getting a Pine Script strategy to actually place trades on MT5 comes down to one thing: firing the right alert with the right message at the right moment. This guide breaks down the two alert mechanisms in Pine — alert() and strategy alert_message — and shows the exact setup that reliably executes through a webhook copier.

alert() vs Strategy alert_message

Pine Script gives you two ways to fire an alert from a strategy. Choosing the right one is the difference between trades that copy cleanly and alerts that silently never fire.

Method 1 — alert_message on Strategy Orders

Attach a JSON payload to every order. When the order executes, TradingView posts that exact message to your webhook. The format follows our TradingView alert JSON guide.

//@version=5
strategy("Breakout Strategy", overlay=true, calc_on_every_tick=false)

longCond  = ta.crossover(close, ta.highest(high, 20)[1])
exitCond  = ta.crossunder(close, ta.lowest(low, 10)[1])

if longCond
    strategy.entry("Long", strategy.long,
         alert_message='{"action":"buy","symbol":"EURUSD","lot":0.10,"sl":50,"tp":100}')

if exitCond
    strategy.close("Long",
         alert_message='{"action":"close","symbol":"EURUSD"}')

Then in TradingView: open Create Alert, set Condition → your strategy, choose "Order fills only", tick Webhook URL, and paste your copier's URL. Leave the message box as the default {{strategy.order.alert_message}} so TradingView substitutes the JSON you defined.

Method 2 — Manual alert() Calls

When you need full control — for example to scale out with partial closes at custom levels — call alert() directly:

//@version=5
strategy("Custom Exits", overlay=true)

if longCond
    strategy.entry("Long", strategy.long)
    alert('{"action":"buy","symbol":"XAUUSD","lot":0.05,"sl":300,"tp":900}',
         alert.freq_once_per_bar_close)

if high >= strategy.position_avg_price * 1.01 and strategy.position_size > 0
    alert('{"action":"close","symbol":"XAUUSD","percent":50}',
         alert.freq_once_per_bar_close)

For alert() calls, create the TradingView alert with the "alert() function calls only" condition. The message box is ignored — Pine supplies the text.

Using Placeholders for Dynamic Values

Hard-coding the symbol and lot works, but you can make a strategy reusable with placeholders that TradingView fills in at fire time:

Wrap every placeholder in double quotes so the JSON stays valid:

{
  "action": "{{strategy.order.action}}",
  "symbol": "{{ticker}}",
  "lot": {{strategy.order.contracts}}
}

Avoiding Repaint and Duplicate Fires

1. Use bar-close evaluation — set the alert to Once Per Bar Close and use alert.freq_once_per_bar_close so signals don't repaint intrabar.
2. Avoid calc_on_every_tick=true unless you specifically want intrabar entries — it can fire and reverse within a bar.
3. Reference confirmed data — use [1] on series in conditions (e.g. ta.highest(high, 20)[1]) so you act on closed bars.
4. One alert per strategy — a single "Order fills only" alert covers every entry and exit; don't stack multiple alerts on the same strategy.

Why Strategy Alerts Don't Fire (Checklist)

• Alert created with the wrong condition (use "Order fills only" for alert_message, "alert() function calls only" for alert()).
• alert_message contains invalid JSON — validate it before going live.
• Alert timeframe differs from the chart the strategy runs on.
• Webhook URL box not ticked, or the copier's URL is wrong.
• Free TradingView plan — webhooks require a paid plan. See our note on which TradingView plans support webhooks.

Still stuck after these? Walk through the full webhook troubleshooting guide.