Twilio: How to map an SMS reply to an original SMS

Question

Im creating an web app that uses twilio and I seem to have a problem.

The system consist of 3 actors:

• A physical customer
• A physical server
• Our web application

Whenever a client creates a new "job" via a form, all of the job details will be sent in a text to many different servers. When any one of the servers reply to that text message, we need to be able to associate his reply with the particular "job" he replied to. The problem is I can't figure out how to do this without buying a number for each job and just associating each number with a job. If possible i would only like to use one number, since buying thousands of number is completely wasteful and impossible.

Answer 1

Cookies are the best way to handle a conversation, but because you cannot tell which text message the server replies to, it can be tricky. If you send the server 2 jobs, and they choose to reply to the first job, you have no way of knowing this.

I think you have two sensible ways of doing this:

• Give each job a reference code (2 or 3 digits to make it easy) that the server can reply with. This is the most reliable way to do it.
• Use multiple - but not many - phone numbers. So that during a period of one day, or a few hours, you only send a server one job per number. Then you can recycle the pool of numbers and reuse them after the job has 'timed out'. This rather depends on what your expect volumes are.