Phone-code sign-in

Owner: Lena Fischer · Epic: ENG-1418 · Shipped: Tuesday 26 May · Shaped in Emargen as "Phone codes for depot workers without email"

Why

Many depot workers have no company email, so they had no way to sign in. A site lead asked for access on their behalf, or shared an account. Greenhollow Dairy and Northgate asked for something better.

What we built

• A person's sign-in can be Phone code. They type their mobile number and get a six-digit code by SMS.
• The number must be in international format and unique in the organisation. One number, one person.
• A code is valid for 10 minutes. Asking for a new code cancels the old one. A new code can be asked for after 60 seconds.
• Five wrong codes, and the person waits 15 minutes.
• SMS go through Textbridge, from the sender name "ACME".
• After signing in, the session is the same as anyone's.
• People on phone codes can't be administrators. Administrators sign in with a password and MFA, or with single sign-on.
• When a depot switches to single sign-on, its people on phone codes keep them.

What we left out

• A voice call when SMS doesn't arrive.
• Messaging apps instead of SMS.
• A second SMS provider. See below.
• Authenticator apps for depot workers: most don't want our app on their own phone.

Rollout

Greenhollow's Mitchelstown site was the pilot from the day it shipped (Greenhollow phone-code pilot). Northgate moved its site workers in June.

Since

• 17 June: Textbridge's outage delayed codes for about two hours (OPS-33). It led to the status page (ENG-1497).
• 15 July: when texts are late, a site's administrator can give one person a one-time code from the portal (People › the person), valid 10 minutes, logged (ENG-1509).
• 9 September: "Text codes through a second SMS provider" postponed. It waits on Textbridge's EU contract.
• 10 September: requests for codes are limited to five an hour per number, as part of the sign-in lockout and rate limits.