Twilio API Contact Center Integration Help! Am I just dumb at APIs?

Need help APIs
1

I am fairly new to Bubble and basically have my app almost to the point where I need to get my api integrations. I am working on a contact center and Twilio is the only live API I currently have. This app will be used in one of my current businesses with plans to make it a saas. For this reason I do not want to use the plugins, this way I do not rely on the developers of the plugin for updates. I am working a basic call and not sure if something is an issue with the bubble api connector, my bubble builder has seemed slightly glitchy. I placed my twillio number in a ‘from’ parameter and my personal cell in a ‘to’ parameter with on final parameter ‘AplicationSid’ pointing to my flow sid. when i initiate a call im getting

‘Raw response for the API
Status code 400
{“code”: 21201, “message”: “No ‘To’ number is specified”, “more_info”: “https://www.twilio.com/docs/errors/21201”, “status”: 400}’

Is the API correct and just not completing as I do not have flows built in bubble to handle this? Current goal is to get a solid working api connection then setup in bubble? Is this backwards?

Any help would be greatly appreciated.

2

p.s. I am entering the numbers in E.164 format

4

Share api connector settings. Did you add content-type header?

5

This is the important bit.

I know you say you input your personal cell number in there. For some reason it’s not working. I looked at the docs and I see there’s a specific format they put the phone number in. Using quotes and the plus sign and starting with your country code.

(So to give you the answer, make your phone number look like this: +15558675310 )

7

Thats the E164 format. I have tried that among many other things.

8

{
“To”: “+18XXXXXXXX4”,
“From”: “+18XXXXXXXX0”,
“ApplicationSid”: “XXXXXXXXXXXXXXXXXXXXXXXX”
}

I have also removed the parameters and placed them in the json body with same result

9

Add content type header

10

Error 21201 usually means Twilio isn’t getting a valid To number in the request. That’s a payload issue, not a Bubble flow problem.

What you need to make sure is:

You’re using To=+15556667777 format (E.164, with + and country code).
Params are sent as application/x-www-form-urlencoded or valid JSON, depending on the API call type.

If you’re using Bubble’s API Connector, double-check key names. Even a missing cap or quote can cause this.

Also, always verify the API works independently (via Postman or cURL) before wiring it into Bubble. Bubble doesn’t validate Twilio’s logic, it just passes data.

If you’re scaling to SaaS, direct API calls work short-term but become messy fast. A full-featured in-app communication SDK like MirrorFly handles calling, flows, and fallback logic natively.