A breach elsewhere can expose your service to an account takeover.
If a customer reuses a password across several websites, credentials leaked from one of them may work on yours. What happens next depends on what the account allows: an intruder might read contracts, download documents or change payout details. Your team may need to help the customer regain access and establish what the intruder did.
Two-factor authentication, or 2FA, helps protect against this kind of sign-in. For a product owner, it involves several decisions: who must use it, how to keep sign-in convenient, and what happens when someone loses their phone. Adding a field for a code is only part of the work.
What a second factor actually changes
A password and the answer to a security question can both be tricked out of a user. Adding another question therefore does not provide the same protection as verifying possession of a device. Even a complex password cannot help if someone enters it on a fake sign-in page.
Stronger authentication does not close every route to account takeover. An attacker may trick someone into handing over a one-time code, while a compromised device can expose an existing signed-in session. The verification method matters, and permissions and application security still need attention.
Which accounts should require more than a password
The consequences of an administrator's account being taken over differ from those of an ordinary customer account. That distinction helps set priorities.
Make 2FA mandatory for administrators and staff with extensive permissions. An account that can export the customer database, change payout settings or grant permissions controls access to other people's data and to the product itself. Leaving protection optional also leaves a risk for the company. Team size does not change those permissions: one person in a small business may still have access to everything.
For customer accounts, consider the data and actions available after sign-in. Confidential contracts need protection even when the user only reads them. A transfer or a change to payout details may warrant an additional check before the operation is completed. A code requested at the transfer stage will not protect documents an intruder has already read.
Account protection: three decisions
Sign-in
Confidential documents and powerful permissions
Verify access at sign-in
Sensitive operations
Transfers and changes to payout details
Verify before the operation
Account recovery
A lost phone or an unavailable factor
Verify account ownership
An account that only saves a collection of publicly available content has a different priority. It can be included in a later rollout stage while more sensitive accounts are secured first. Check that the apparently simple account really contains no confidential data or ability to act on a customer's behalf.
Record which capabilities the product must never expose behind a password alone. When a new feature is added, the team can apply the relevant sign-in requirements immediately. Industry and legal obligations need a separate assessment; reviewing account permissions does not replace it.
Stronger protection can still be convenient
Mandatory 2FA does not mean asking customers to pick up their phone every time they open a page. A product can preserve an authenticated session and request verification again in defined situations: sign-in from another device, a security setting change or a sensitive operation. The conditions depend on what the service protects.
The method also affects convenience. SMS codes, authenticator apps and passkeys work differently.
SMS
There is no extra app to install: a code arrives at the registered number. The service pays for messages and relies on delivery. A customer without reception may be unable to sign in at that moment.
The number itself can also be taken over. If an attacker persuades a carrier to transfer it to another SIM, the codes reach the attacker. A code can also be captured through a fake sign-in page. SMS can be considered an interim improvement over a password alone, while administrators and high-impact operations warrant more resilient methods.
Authenticator apps
An authenticator generates one-time codes on the phone. Once configured, it needs neither an internet connection nor mobile reception to generate them. There is no message to wait for. During setup, however, users need clear guidance on connecting the app to their account and retaining access when they replace their phone.
An app-generated code can still be captured on a fake website. For accounts with extensive permissions, that is a reason to consider a method that also verifies the website involved in sign-in.
Passkeys
A passkey lets someone approve sign-in with a fingerprint, facial recognition or their device PIN. Verification is bound to the genuine website, so a fake page does not receive a reusable sign-in code. Staff can also use separate hardware security keys that support this protection.
With an appropriate configuration, the device and its local unlock provide two factors. The user does not copy a code and may not need to enter a password at all. Stronger protection can therefore remove an extra step. Google's passkey guide shows how this works for users.
The choice depends on the devices people use. Within a team, devices can be agreed on and security keys issued to staff. A consumer service must accommodate different phones, browsers, shared computers and backup sign-in methods. The development team needs to check those conditions before making the new protection mandatory.
Restore access without giving it to an intruder
A user loses their phone, or replaces it without transferring the authenticator, and can no longer obtain codes. This scenario is part of implementation too. Otherwise, a company can end up with a protected account its owner cannot enter and support requests the team is not ready to handle.
Single-use recovery codes or another enrolled device provide a backup route. Offer that route during setup, while the user still has access. Explaining the need to save codes after they have been lost will not help. If every verification method is gone, a separate recovery process is needed; immediate restoration cannot be promised.
What to ask the development team to deliver
First, establish which scenarios the existing sign-in system supports. The appropriate methods, mandatory protection for selected roles and recovery may already be available in its settings. In that case, configuration and verification may be enough. Development work is needed when the system cannot enforce the chosen rules or leaves another sign-in route without the required protection.
Start by testing the rollout with a limited group. This helps check whether setup is understandable, the selected methods work on the necessary devices and support can handle lost access. Explain the changes to other users in advance and give them time to enrol before protection becomes mandatory.
For acceptance, ask the team to demonstrate four things:
- An account that requires 2FA cannot be opened with a password alone through the website, mobile app or another user-facing sign-in route.
- An operation that requires extra verification cannot complete without it. Switching to another screen does not bypass the rule.
- Recovery follows the agreed process: an owner with the required evidence can regain access, while an intruder cannot simply ask for protection to be disabled.
- The team can see sign-in and enrolment errors, support requests and the share of users who have not completed setup. It can identify where they stopped.
Use those observations to fix specific obstacles. When a message fails to arrive and the screen only offers another attempt, the mere presence of 2FA does little for that customer. The implementation has to account for those situations as well.
If introducing 2FA means changing sign-in, permissions or account recovery, the work spans several parts of the product. Design them together so the new rules apply across the intended scenarios.
At EL Pixel, we can help design these changes and implement 2FA in your product. Tell us what the service does and how users sign in today. We can discuss the data and actions that need protection and the changes involved. You do not need a finished technical specification for the first conversation.
