What is webhook idempotency and why does a trading connector need it?

What this means in practice

Idempotency means receiving the same signal multiple times does not create multiple trading effects. It is essential because networks retry and TradingView can resend certain failed 5xx webhook deliveries. This page is specifically about “What is webhook idempotency and why does a trading connector need it?”, so each scenario below is explained by its own mechanism instead of sharing one generic diagnosis.

Real-world scenarios

Scenario A — 500 returned after trade queued

Treat this as duplicate-delivery risk. If the first request was already persisted or queued before the error response, a resend must reuse the same signal ID and produce no second trading effect. For Scenario A — 500 returned after trade queued on question 32, use that evidence specifically to answer “What is webhook idempotency and why does a trading connector need it?”; keep it separate from the evidence for the other scenarios on this page.

Scenario B — Same signal arrives twice

Inspect the mechanism named by “Scenario B — Same signal arrives twice” directly. Record its input, the state immediately before it and the first observable output that differs from the intended result. For Scenario B — Same signal arrives twice on question 32, use that evidence specifically to answer “What is webhook idempotency and why does a trading connector need it?”; keep it separate from the evidence for the other scenarios on this page.

Scenario C — Restart during processing

Inspect the mechanism named by “Scenario C — Restart during processing” directly. Record its input, the state immediately before it and the first observable output that differs from the intended result. For Scenario C — Restart during processing on question 32, use that evidence specifically to answer “What is webhook idempotency and why does a trading connector need it?”; keep it separate from the evidence for the other scenarios on this page.

What to check

• TradingView alert log and exact send time
• HTTP status and receiver timestamp
• validated payload plus signal ID
• cTrader result only after transport is proven

Practical rule

For “What is webhook idempotency and why does a trading connector need it?”, change only the first layer whose evidence no longer matches the intended action. Preserve signal identity, timestamps and final cTrader state, and reproduce execution-affecting changes on demo before live use.