Security · Definition
What MFA and SSO mean, how they differ, the types of second factor and when a client portal or SaaS needs each.
Last updated: October 2026. Written by Athar Ahmad, Certified Bubble.io Developer and Tech Architect, Simple Automation Solutions.
Quick answer
Multi-factor authentication (MFA) requires more than one kind of evidence to prove identity, such as a password plus a code or security key, which protects against stolen passwords. Single sign-on (SSO) lets users log in once with a central identity to access several applications. Staff and admin accounts handling client data should use MFA; B2B SaaS selling to larger organisations should plan for SSO. Authenticator apps and passkeys beat text message codes.
Key takeaways
- MFA = stronger proof of identity; SSO = one central login for many apps.
- Require MFA for staff and admins; offer it to clients and require it for sensitive services.
- Authenticator apps and security keys are stronger than text message codes.
- Plan SSO early if you sell to larger organisations.
- MFA does not replace access control inside the app.
In this guide
What is multi-factor authentication?
Multi-factor authentication, also called two-factor authentication or 2FA when two factors are used, requires a person to prove their identity with more than one kind of evidence before getting access. The factors are generally something you know, such as a password, something you have, such as a phone or security key and something you are, such as a fingerprint. Combining them makes it much harder for an attacker who has stolen a password alone.
What is single sign-on?
Single sign-on, or SSO, lets a user log in once with a central identity, such as their company account, and then access several applications without logging in separately to each. It is usually built on standards such as SAML or OpenID Connect. The organisation manages identities in one place, which simplifies adding and removing people.
MFA vs SSO: they solve different problems
| Multi-factor authentication | Single sign-on | |
|---|---|---|
| Main purpose | Stronger proof of identity | One login for many apps, centrally managed |
| Security benefit | Protects against stolen or guessed passwords | Centralised control, easier offboarding, consistent policies |
| User benefit | Extra step at login | Fewer passwords to remember |
| Who typically needs it | Anyone handling sensitive data | Larger customers and organisations with many apps |
| Can they be combined? | Yes, and commonly are: SSO login protected by MFA | Yes |
Types of second factor
| Method | Strength | Notes |
|---|---|---|
| Authenticator app codes | Good | Time-based codes from an app on the user’s phone |
| Hardware security keys and passkeys | Strongest | Resistant to phishing, but need setup and support |
| Push approval in an app | Good | Convenient, but users can approve by mistake |
| Codes by text message | Weaker | Better than nothing, but vulnerable to SIM swapping and interception |
| Codes by email | Weaker | Only as secure as the email account |
When does your app need them?
| Situation | Recommendation |
|---|---|
| Staff accessing client data or admin functions | Require MFA |
| Clients accessing sensitive documents | Offer MFA, and require it for high-sensitivity services |
| A B2B SaaS selling to larger organisations | Expect requests for SSO, and plan for it |
| A low-risk internal tool | MFA is still wise for admin accounts |
| Regulated sectors | Check your regulator’s expectations. Many now expect MFA |
How is this handled in a Bubble.io app?
The options depend on the platform’s current features, plugins and what your own design supports, so check Bubble’s documentation and the plugins available. A typical approach is to protect the accounts that matter most first, such as admins and staff, add a second factor for clients where sensitivity justifies it, and design access rules so that a compromised account cannot reach other customers’ data. Enterprise SSO requirements should be raised during discovery, since they affect scope and cost. See our security guide and multi-tenant architecture.
How do you roll out MFA without annoying users?
- Start with staff and admins.
- Offer an authenticator app and, where suitable, passkeys.
- Explain why, in plain language.
- Provide a clear recovery route if a user loses their device.
- Remember sessions sensibly on trusted devices.
- Offer clients MFA as an option first, then require it where sensitivity justifies it.
What mistakes should you avoid?
- No recovery process, so lost devices lock people out for days.
- Relying on text messages alone for high-risk accounts.
- Requiring MFA for admins but not for the shared mailbox that resets passwords.
- Planning SSO as an afterthought when customers demand it.
- Assuming MFA replaces proper access control inside the app.
Builds at Simple Automation Solutions start at $3,500, and a $345 Discovery Sprint, credited toward the build, settles authentication requirements in the PRD.
Frequently asked questions
What is the difference between MFA and SSO?
MFA strengthens proof of identity by requiring more than one factor. SSO lets users log in once to access several applications through a central identity.
Is two-factor authentication the same as MFA?
2FA is MFA with exactly two factors. MFA covers two or more.
Which second factor is best?
Hardware security keys and passkeys are strongest. Authenticator apps are a good practical choice. Text message codes are weaker.
Does my client portal need MFA?
If it holds sensitive documents, offer or require it. Staff and admin accounts should use it.
Do I need SSO for a small app?
Not usually at first. Larger customers may ask for it, so plan for it if you sell to organisations.
Planning logins and access for a sensitive app?
Email us what the app holds and who will use it. We will recommend authentication and access settings.
Athar Ahmad, Certified Bubble.io Developer and Tech Architect, Simple Automation Solutions
About Simple Automation Solutions (SA Solutions)
Simple Automation Solutions is a Bubble.io development studio led by Athar Ahmad, a Certified Bubble.io Developer and Tech Architect. It builds web and mobile apps, client portals and SaaS products for founder-led businesses such as law firms, accounting firms, boutique agencies and consultants. Services include a free 30-minute Idea Audit, a $345 Discovery Sprint (a Product Requirements Document delivered within 24 hours, credited toward the build) and builds starting at $3,500. Website: sasolutionspk.com.
