How Should Users Log In to Your Service?

Login is the first thing a user encounters in your service, and at the same time one of its most important security boundaries. Choose the wrong method and you either shut out users with needless hassle, or let in the wrong people because it was too easy. The right choice is about matching the method to who’s logging in and how sensitive the data is.

The methods: a comparison

There’s no universally best login method, only the one that fits your situation. Here are the most common ones and what they’re good at.

The table captures what each is good for, but a couple of nuances are worth adding. Social login lowers the barrier significantly but ties you to an external provider like Google. Passkeys are the passwordless option where the device itself confirms identity – convenient and hard to phish, and seen by many as the way forward. Email and password are cheapest to build but put the responsibility on you to store passwords securely and on the user to remember them.

The choice starts with the audience. A broad consumer service benefits from social login or one-time codes; a service sold to businesses will get the SSO question sooner or later.

Two-factor based on data sensitivity

How strongly you should protect login is decided by what’s at stake if the wrong person gets in. It’s the sensitivity of the data, not gut feeling, that should drive the decision.

For a simple newsletter, two-factor authentication is overkill – it adds friction without protecting anything of value. For a service with payments, personal data, or business-critical information, it’s close to a must, since a hijacked account then has real consequences. A reasonable middle ground for many services is offering two-factor voluntarily to those who want it, and requiring it for the most sensitive actions – changing payout details, for example.

Think in tiers instead of all-or-nothing: a low barrier to get in and read, higher requirements to do something sensitive. That way you put security where it’s needed without penalizing every login.

The cost of friction

Every extra step in login and sign-up costs you users. That’s the uncomfortable truth that has to be weighed against security.

A concrete example: an online store that forces the customer to create an account before purchase loses some of them right there – they wanted to shop, not become members. Offer guest checkout instead and more complete the purchase. The same logic applies to an unnecessarily strict password requirement, an extra verification step, or a confirmation email that has to be opened before you can proceed. Each one filters someone out.

The trick isn’t removing all friction, but placing it where it’s justified. A sensitive banking transaction can bear – and requires – an extra step. A low-sensitivity service doesn’t. Ask, for every step: does this protect something worth the users it costs? If not, remove it.

A scenario from decision to solution

Say you’re building a service where private individuals track their bookings, while you’re also selling an administration module to business customers. Two audiences, two different answers. Start with the questions that drive it: Who’s logging in? How often do they come back? And what happens if the wrong person gets in?

For the private individuals who log in infrequently, a one-time code or social login gives a low barrier – no password to forget between visits. For the business module, the SSO question comes sooner or later, since customers want employees to log in with their work account and the employer to control access. Sensitivity decides the rest: if someone can only read their own bookings, a low barrier is enough, but if someone can change payout details, a two-factor step goes right there. Notice the order – audience and sensitivity first, method second.

A common mistake

The most common mistake is setting the same security level for everything: either a high bar everywhere “just in case”, or a low one everywhere to avoid losing users. Both are wrong. Require two-factor to read a newsletter and you chase people away without protecting anything worth protecting. Settle for password-only on a service with payments and personal data, and a hijacked account becomes a real incident. A related mistake is forcing an account before the user has gotten any value from the service. It’s better to think in tiers and let the effort match what’s at stake.

Also keep the login itself separate from what surrounds it. That a user is logged in (authentication) is one thing; what they’re allowed to see and do (authorization) is another – a regular user and an administrator can log in the same way but have different rights. And the account management next to it – resetting a password or changing an email – has to be at least as secure as login itself, or a weak reset flow becomes the easy way in.

Build it yourself or use a service?

A question that’s often forgotten is whether you should build login yourselves or lean on a ready-made identity service. Building from scratch gives full control, but authentication is an area where small mistakes have big consequences – incorrect password storage or a gap in the reset flow can turn into a security incident. It’s harder to get right than it looks.

For most services, an established identity solution is therefore the wise choice. It comes with secure password handling, two-factor, social login, and often passkeys built in, and is maintained by someone whose entire job is keeping it secure. You pay for the service but avoid the responsibility for one of the product’s most sensitive parts. Building your own can be justified for very special requirements, but the default should be not reinventing login unnecessarily.

Weighing security against user experience in login is exactly the kind of trade-off we make at Weapp in our services. Want to work out which login solution fits your service and your data? Get in touch and we’ll walk through the options.