The new FxA "devices" API [1] will define several new error codes that can be returned when interacting with the FxA auth server endpoints. These error codes will need to be added to FxAccountsCommon.js [2] [1] - https://github.com/mozilla/fxa/blob/phil/fxa-45-requirements/features/FxA-45-device-registration-api/README.md [2] - https://dxr.mozilla.org/mozilla-central/source/services/fxaccounts/FxAccountsCommon.js#249

Phil, can you let me know whenever you have defined the new error codes?

Sorry for taking so long to get round to this. There are two new errors: AppError.unknownDevice = function () { return new AppError({ code: 400, error: 'Bad Request', errno: 123, message: 'Unknown device' }) } AppError.deviceSessionConflict = function () { return new AppError({ code: 400, error: 'Bad Request', errno: 124, message: 'Session already registered by another device' }) }

Actually, I think there may be one more too: AppError.deviceSessionConflict = function () { return new AppError({ code: 400, error: 'Bad Request', errno: 125, message: 'Session already registered by another device' }) }

Wait, I already mentioned that one. Ignore my last comment, it's Friday, late and I'm tired. :-/