SSO Tax

What is the SSO tax?

Single sign-on (SSO) lets your team log in to many apps with one company login, managed in your identity provider. SAML is the most common business standard for it.

The SSO tax is the price gap when a vendor offers SSO only on a higher plan. To get one security feature, you pay for the whole upgraded tier, for every seat.

Slack's pricing page comparison table, as of October 2026, lists SAML-based SSO for its Business+ and Enterprise+ plans, and "OAuth with Google" for Pro. Pro costs $7.25 per user per month billed annually. Business+ costs $15 per user per month billed annually.

For a team of 40 on annual billing, that is about $3,480 a year on Pro and $7,200 a year on Business+. The upgrade brings other features too, but if SSO is the reason you move, the gap is what SSO costs you.

Why it matters to you

SSO is how you remove access in one place when someone leaves. Without it, vendor offboarding and employee offboarding mean finding and closing separate accounts by hand.

Your own customers may ask about it. A security questionnaire from an enterprise buyer often asks how you control access to the tools that hold their data.

The tax also shapes behavior. If SSO is too expensive, teams skip it, and accounts end up outside your control, which is how shadow IT grows.

What to check

• Check which plan includes SAML SSO and automated user provisioning, not just "sign in with Google."
• Ask whether SSO is available as an add-on on a lower plan.
• Price the upgrade across all seats for the full term, then compare it with the risk of manual offboarding.
• Get any SSO discount or add-on written into your order form so it survives renewal.
• Watch for plan changes that move SSO to a higher tier at your next renewal.

How Venpo helps

Venpo monitors your vendors' terms and other public legal and billing pages, and emails you in plain English when plan or pricing terms change. The Fine Print Scan answers whether each vendor can raise prices, including through plan changes like these.