WhatsApp as alternative to SMS for sending OTP in Verification

[fungc-io]

Problem

• The reverse OTP mechanism was unpopular
• Meta has announced a price drop for outbound WhatsApp messages for verification purposes, making it a viable alternative to SMS verification.

Solution

• Remove the old reverse OTP mechanism in WhatsApp
• Reimplement the WhatsApp integration as another channel for OTP phone verification in signup/login.

Appetite

2 weeks

[tung2744]

Wati

Pricing

https://support.wati.io/l/en/article/1w0qfawav7-conversation-based-pricing-our-new-pri

0.051 USD / conversation in hong kong (Authentication template) 0.0566 USD / conversation in hong kong (Utility template)

Message Template

Authentication

• Cheapest
• No customization allowed (Cannot display the app name in the message)

Utility

I tried to create a template with the following content.

{{AppName}}
Your one-time password is {{Code}}

But it will reject my template. I can request a review but I am not sure if it would pass the review because utility templates are not for authentication.

Whatsapp (Cloud-api)

Pricing

https://scontent-hkg4-1.xx.fbcdn.net/v/t39.8562-6/343340495_556945759927254_5506526186653119432_n.csv?_nc_cat=103&ccb=1-7&_nc_sid=ae5e01&_nc_ohc=MP6l2nI4YQgAX_62glj&_nc_ht=scontent-hkg4-1.xx&oh=00_AfAWGChNZ0dMt4M4LnpwsfobP4QBVekdOUsanhaBW98vRw&oe=64695250

• 0.0304 USD / authentication conversation in hong kong (Other region)
• 0.0338 USD / utility conversation in hong kong

Problem

• Need to find a phone number and attach to the whatsapp account

[tung2744]

@fungc-io It seems the restriction of authenticate template make it unusable in authgear, because we cannot display the app name in the message. And also it seems not possible to use other templates for authenticate purpose.

[fungc-io]

@tung2744 Can we customize the message to display the app name if we use the Official API and use our own phone number?

[tung2744]

@fungc-io The templates are defined by facebook. For authentication, there is only one non-customizable template.

However, yesterday I finally made a template with utility type which can be submitted for review. https://business.facebook.com/wa/manage/message-templates/?business_id=10153179122721485&waba_id=107153018658275

And it was just approved.

[tung2744]

Asked here https://business.facebook.com/direct-support/question/571803688274436/?force_full_site=0&business_id=10153179122721485

[tung2744]

@louischan-oursky @fungc-io Do you think we should have separated rate limit configs for whatsapp?

[fungc-io]

I think so as we have granular controls for other channels too

[tung2744]

@fungc-io Facebook said they increased the number limit of the Whatsapp business account and I've successfully added the number. However a new whatsapp account was created, could you help setup payment there?

[fungc-io]

@tung2744 , added, please try again

[fungc-io]

Ready on staging, pending deployment Follow up in #3137