# POST /gateway/transact.dll is deprecated

Authorize.net AIM/SIM deprecated POST /gateway/transact.dll without giving a shutdown date yet.

Authorize.net deprecated POST /gateway/transact.dll without a shutdown date. Calls hitting this endpoint will fail under the planned removal. The deprecation covers both AIM integrations and SIM payment forms that submit to this gateway path.

## What to use instead

Move AIM calls to the Authorize.net API by using createTransactionRequest on the newer XML or JSON request endpoint. Replace SIM payment forms with Accept Hosted, which requires configuring a new hosted payment page rather than simply switching an endpoint.

SIM's hosted form moves to Accept Hosted, a different hosted payment page the merchant configures anew.

- API: Authorize.net AIM/SIM (secure.authorize.net)
- Kind: Endpoint removal
- Takes effect: no date given yet
- Calls after that day: fail
- Calls it hits: `POST /gateway/transact.dll`
- Source: [Announcement](https://developer.authorize.net/api/upgrade_guide.html)
- Verified: October 27, 2026, against Authorize.net AIM/SIM's own pages
- Page: https://www.okapi.bot/providers/authorize-net-aim-sim/breaking-changes/post-gateway-transact-dll-is-deprecated/

## Authorize.net AIM/SIM's words

> AIM | Deprecated | Authorize.net API | SOAP API | Deprecated | Authorize.net API | SIM | Deprecated | Accept Host |

Okapi finds the calls this change hits in your repo and opens the pull request with the fix: https://github.com/apps/okapi-agent