Two-factor authentication (2FA) adds a second layer of security to your login. After entering your email and password, you must enter a 6-digit verification code before access is granted. This means that even if someone knows your password, they cannot log in without also having access to your phone or email.
2FA is mandatory on FastKnowledge — it cannot be disabled. Every login requires it unless the device is trusted (see "Remember Me" below).
Who can use this?
All users. 2FA is required for every login.
How 2FA works
After a correct email + password combination is entered:
1. A 6-digit code is sent to your registered phone via SMS (default channel).
2. If SMS delivery fails, the code is sent to your email as a fallback, and a warning is shown on screen.
3. You enter the 6-digit code on the verification page and click Verify.
Code validity
- Codes are valid for 10 minutes.
- After 5 incorrect attempts, your login session is invalidated and you must start over from the login page.
Setting up your phone number
If you have not yet registered a phone number, you will be prompted to do so on your first login:
1. Enter your phone number with the country code (for example: `+155525256666`).
2. Click Send Code — a 6-digit SMS code is sent to that number.
3. Enter the code on the next page to verify your phone.
4. Your number is saved. This step only happens once.
The phone number must include an area code.
The minimum accepted length is 10 digits (excluding the `+` prefix and country code separator).
Switching between SMS and email
On the 2FA verification page you can switch the delivery channel at any time:
- Click Send code via Email to receive the code in your inbox.
- Click Send code via SMS to switch back to your phone.
Each click sends a new code to the selected destination. The previous code is still valid until it expires or until the new one is consumed.
Resending a code
If a code did not arrive (SMS delay, full inbox, etc.):
1. On the verification page, click Resend Code.
2. A new code is sent via the active channel (SMS or email).
Remember Me — skipping 2FA on trusted devices
When you log in, you can check Remember me to create a trusted-device token that lasts 30 days. While this token is active:
- You can log in from the same browser on the same network without entering a 2FA code.
- The trust token is tied to your browser, your current IP/network, and your password hash.
Any of the following will invalidate the token: changing your password, switching to a different browser and connecting from a different network or Wi-Fi.