What is idempotency?
Idempotency means doing the operation again does not do the job twice. The second identical request is recognized and ignored or safely folded into the first. An idempotency key is the id you use to notice the repeat.
Also called: idempotency key
In plain English
Webhooks retry. People double-click. A workflow that texts a customer on every delivery will text them twice when the network hiccups. The fix is to store the event id and skip ids you have already handled. That is the key, not a vibe. Pick the id that means 'this already happened.' A payment id, a booking id, a form submission id. Store it. If the same id shows up again, do not charge, text, or create a second job. Test by sending the sample twice on purpose. If you get two customers out of one form, you do not have idempotency. You have a duplicate machine. Log the skipped duplicate so you can prove the second ping was ignored, not lost. A silent skip with no log looks like a bug to the next person. Stamp the ignored replay with the original receipt number. Engrave that number on the skip line.
How an owner would use it
For any step that charges, books, or messages, decide the id that makes it the same event. Test by sending the sample twice. If two texts go out, you are not done.
Common mistakes
Using the customer's email as the only key merges two different events from the same person, or splits one event that came from two addresses. Pick the id the sending system already uses. Do not assume the automation vendor dedupes for you unless you have tested their current behavior. Deduplication of records in a CRM is a related cleanup, not a substitute for this.
A worked example
A catering company
One deposit link, even if the form fires twice
This is an illustration, not a customer result. The inquiry form sometimes delivers two webhooks with the same inquiry id. The workflow stores that id. The second delivery does not create a second deposit link or a second email. The coordinator sees one lead.
Related terms
Prompts and guides
Questions owners ask
What is idempotency?
It means repeating the same request does not repeat the side effect, such as a second charge or a second text.
How do I make a customer workflow idempotent?
Store the source event id and skip work you already did for that id. Test with a duplicate delivery before you go live.
What is an idempotency key?
It is the id you store to recognize a repeat. It should come from the system that created the event, not from a random new number on every retry.
Product guides are on AI apps for business.