---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/61006#article
headline: "61006: Add-ons: Add-ons unavailable for GET callbacks"
url: https://www.twilio.com/docs/api/errors/61006
inLanguage: en
dateModified: 2026-06-08T11:29:20.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 61006: Add-ons: Add-ons unavailable for GET callbacks

Log Level: WARNING

## Description

This warning appears when you use a Twilio Marketplace Add-on with an incoming Messaging or Voice webhook that is configured to send `GET` requests. Twilio does not include Add-on results in `GET` callbacks because URL length constraints can prevent the `AddOns` payload from being delivered.

### Possible causes

* Your incoming Messaging webhook is configured to use `GET`. Add-on results for Programmable SMS are only included in `POST` callbacks.
* Your incoming Voice webhook is configured to use `GET`. Add-on results for Programmable Voice calls are only included in `POST` callbacks.
* Your application expects the `AddOns` parameter in the callback even though the request method is `GET`. Twilio omits that data from `GET` callbacks for these Add-on usage points.

### Possible solutions

* Change the incoming webhook method to `POST` for the Messaging or Voice flow that invokes the Add-on. Twilio supports both `GET` and `POST` for these webhooks, and `POST` is required when you need Add-on results in the callback.
* Update your application to read Add-on results from the `AddOns` parameter in the `POST` request body after you switch the webhook method.
* If you need `GET` for caching static TwiML or webhook responses, do not rely on Add-on data in that callback. Use `POST` for the endpoint that must receive Add-on results.

#### Additional resources

* [How to Use Marketplace Listings](/docs/marketplace/listings/usage)
* [Messaging Webhooks](/docs/usage/webhooks/messaging-webhooks)
* [Voice Webhooks](/docs/usage/webhooks/voice-webhooks)