MSG91 is a CPaaS platform to help you communicate with your users on multiple channels that provides secure and robust APIs and ready-to-use tools.
Click here for Login/Signup- https://control.msg91.com/signin/
Communication Channels-
a. SMS
b. WhatsApp
c. Email
d. Voice
From the Sender ID approval process to creating templates and sending SMS - Follow its doc here
From creating a Facebook Business account to adding the number and templates- Follow its doc here
For full Email configuration from adding a domain to sending Email - Follow its doc here
From creating templates to sending voice- Follow its doc here
Use Hello when you want to-
i) Manage your customer email tickets
ii) Facilitate your customer with live chat and view its analytics
iii) Create internal teams to manage email tickets and live chat
iv) Connect your customer on call or on-screen sharing
v) Manage your Help articles/docs and publish them for customers
Step by Step guide to start Segmento and utilize it fully-
i) Update your existing user data by CSV.
ii) Add API to bring new users and new user fields/attributes/events.
iii) Create Segments
iv) Send messages over SMS, WhatsApp, Email, etc. (run campaign) manually to all users of a particular segment or Automate based on user falls in any segment.
Use the Send OTP API for sending OTP SMS and using voice as backup in retry with the Resend OTP API and verifying the OTP via the Verify OTP API.
Or you can integrate the Login with OTP Widget on your end and all these 3 APIs (Send, Resend, and Verify) will be called automatically. HelpDoc
Integrate a single Campaign API for all channels - HelpDoc [Recommended]
For very specific use case which is not being solved by Campaign APIs
Use dedicated APIs -
i) For SMS
ii) For Email
iii) For Whatsapp