Modify and replay a webhook

Many webhook bugs only appear with a particular value: a missing email, an amount sent as a string, an unexpected status. Modify & Replay takes a real captured event, changes what you specify, and sends the result. The original event stays exactly as it was.

In the terminal

hwcli replay evt_93df18ab \
  --set data.amount=5000 \
  --set data.customer.email=null \
  --remove data.metadata \
  --header "X-Test-Mode:true"

--set values are JSON when they parse (5000, null, true, {"a":1}) and strings otherwise. Paths use dots and brackets: data.items[0].price. You can also change --query, --method, --path and --content-type, or replace the whole body with --body-file.

--edit opens the full request (method, path, headers and body) in $VISUAL or $EDITOR. Save and close to send it.

In the dashboard

Modify & Replay shows the original and the modified request side by side, with every change listed before you send. After it runs you see the response next to the original delivery's response.

What is kept

• Only the parts you change are rebuilt. An unmodified body is sent as the exact original bytes.
• The replay stores your changes, not a second copy of the body, and links back to the original event.
• A body change invalidates the provider's signature. Add --resign to sign the modified body with the stored secret, or test the failure path on purpose (see signature testing).

Modify & Replay is included on every plan, including Free.