Why Is Single Sign-On (SSO) Considered a Core Security Requirement?

Single sign-on (SSO) is considered a core security requirement because it gives IT and security teams one place to onboard, manage, and offboard users, and to centralize controls like strong authentication, logging, and account recovery. According to sso.tax, SSO is a core security requirement for any company with more than five employees. That threshold matters: once a team is large enough that people share tools and turnover happens, managing access account-by-account stops being practical and starts being a risk.

What SSO actually does

SSO is the mechanism behind "log in once, access everything." If you have ever used Okta, Google, or a social account to sign into another website, you have used SSO.

For users, it is convenient: one password, one time, maybe a security key, gets you everywhere. It is quick and requires little thought.

For IT and security teams, the value is different in kind, not just degree. A modern company uses dozens, if not hundreds, of software vendors. SSO provides:

• A single place to onboard, manage, and offboard users — when someone joins or leaves, access is changed in one system rather than across every vendor.
• Centralized security controls — strong authentication, logging, and account recovery all live in one place instead of being reimplemented per app.

For software vendors, SSO also shifts responsibility: if a customer demands a new hardware authenticator, the vendor does not have to build support for it — that is the SSO provider's job.

Why "core" is the right word

The argument is not that SSO is a nice feature. It is that the alternative — per-app passwords and per-app user management — does not scale past a small team, and the failure modes are security failures: orphaned accounts, weak or reused credentials, and no central log of who accessed what.

sso.tax frames this directly: SSO is a core security requirement for any company with more than five employees. Below that size, manual account management may be tolerable. Above it, the company is choosing between a secure environment and an affordable budget if SSO is paywalled.

The pricing problem sso.tax documents

Some vendors exploit the fact that SSO is a requirement. They offer competitive starter plans and gate SSO behind an "Enterprise" paywall, bundled with unnecessary features or large minimum seat counts. According to sso.tax, this can inflate cost by 3x, 5x, 10x, or more.

The site's own guidance is a useful test: if a company claims to "take your security seriously," SSO should be included in all plans or available for a reasonable charge.

Examples from the sso.tax price-increase table

The table lists base pricing versus SSO pricing, the resulting increase, and the date the entry was updated. A sample:

The pattern is the point: the same product, the same security control, priced as a luxury rather than a baseline. The site also flags "Quotes Required" as a separate category, meaning some vendors do not publish SSO pricing at all.

How to use this when evaluating a vendor

1. Find the vendor's SSO pricing — check the pricing page linked from sso.tax if the vendor is listed.
2. Compare it against the base plan, not against the vendor's "Enterprise" bundle as a whole. The relevant number is the increase, as shown in the table.
3. Check whether SSO is bundled with features you do not need or a minimum seat count you cannot meet.
4. Apply the sso.tax test: is SSO included in all plans, or available for a reasonable charge? If not, the vendor is treating a core security requirement as an upsell.

For a company with more than five employees, that last question is the deciding one — the cost of the SSO tier is the cost of doing business securely with that vendor.