@Jorge Martínez According to the workflow, the initial trigger begins with the Telegram trigger and proceeds through an HTTP request to retrieve the payment link, which is then sent to the user via the Merge node as a response. When a user clicks on a payment link, it is routed to a Webhook, which checks for Success or Failed before returning to the Merge node and Telegram response. If I am understanding correctly, there is a problem here. When you use a Webhook trigger, no Telegram user data is included. To resolve it there are many ways to do it. The important aspect is to keep the user chat ID. Solutions: 1. Save and append the user chat ID to the Payment Link so that Webhook can identify and retrieve it when triggered. 2. Save it in your workflow so that it can be passed to the Telegram response. 3. If you know the chat ID and it is fixed (for example, a Telegram bot), you can hardcode it into the Telegram response. I hope I was able to understand your situation.

@Jorge Martínez For option 2, you will need to store the data into a table with fields like chat ID and payment ID or any unique identifier. When the webhook is triggered, retrieve data with a unique identifier, such as a payment ID that matches the webhook payment ID, get chat ID from the table associated with that payment ID, and pass it to your Telegram response.

As @Kenan Kurtuluş said, you will need to add the account as a test user under the OAuth consent screen: From the dashboard, navigate to APIs & Services and click OAuth consent screen. Add a test user and, if your API has restrictive access, enter your n8n domain to grant access.

What tools, platforms, or frameworks are you planning to use? I might be able to help.

@Ryan Nickel Although it has limitations, widgets can be added to a client's website to provide interactive tools. If you want a completely customized user interface, I would recommend looking into Pydentic AI, which is a very strong framework. GoHighLevel will be a better option, but all three can be accomplished with n8n.