PSI use the concepts of vouchers to track referrals issued to clients for the purpose of tracking uptake of product and services

5 digits

...

Voucher number characteristics

• 6 characters in length (letters and digits)

• Letters are all capitals

• we don’t use I or L letters - instead we use 1 only

• we don’t use O (capital 0), instead we use 0 (zero) only

+ 1 digit

remainder of the Sum of the previous 5 digits

...

• First 5 characters are ramdomly generated

• Last 1 character is a control character, calculated by Summing the first characters, and then taking the reminder.

Typical voucher operations

• every 24h cron job + node.js: fills the pool of draft ServiceResquest Ids to 10,000

• an application ask for X of draft id, then they get marked as on-hold

• A bot as for a voucher: draft → active

• A voucher is redeem: active → completed