The authentication pattern enterprise customers refuse to buy without — and the difference between adding it in a week and rolling your own SAML for a quarter.
Research-based overview. This article synthesizes public documentation, pricing pages, and user reports. How we research.
For a solo SaaS founder, SSO usually arrives as a sentence in a sales call: “Before we move forward, our IT team will need this to integrate with Okta.” The customer is asking whether your product supports SAML SSO. The answer determines whether the deal closes. Most products that do not support it lose those deals; most products built on a modern auth provider can ship support in a few hours; the ones that try to roll their own SAML implementation end up with a quarter-long detour and a security audit.
This page covers what SSO actually is, the protocols underneath it, the Identity Providers that dominate the market, and the practical advice for a solo founder: when to add it, how, and how much it costs.
Three groups demand SSO, and they are the same group: enterprise IT departments, security-conscious mid-market companies, and any organization with a compliance auditor.
The practical version of this story for a solo SaaS founder: an enterprise customer's IT team will not buy your product without SSO. It is table stakes for any deal above roughly $10K ACV. Below that, the customer is usually a small team, the buyer is a manager rather than a CISO, and email-and-password is acceptable.
Two protocols cover almost every real-world SSO deployment.
SAML (Security Assertion Markup Language) is the older standard, ratified by OASIS in 2005. It is XML-based and was designed in the era of enterprise web portals. The flow involves an XML “assertion” signed by the IdP and POSTed to your application via the user's browser. SAML is verbose, idiosyncratic in places, and the canonical choice for enterprise IT. Almost every IdP an enterprise uses speaks SAML; almost every “we need SSO” conversation in B2B sales actually means SAML 2.0.
OpenID Connect is the modern alternative, layered on top of OAuth 2.0. It is JSON-based, uses signed JWTs as the assertion format, and has cleaner mobile and SPA flows. Specifications live at openid.net/connect. OIDC is what “Sign in with Google” and “Sign in with Apple” are built on. For new enterprise integrations, IdPs increasingly support both SAML and OIDC, and OIDC is technically the cleaner choice. In practice, SAML still dominates because the enterprise customer's existing IdP setup uses it, and an IT admin pasting SAML metadata into your app is the path of least resistance.
The take-away: support both if you can, but if you only have time to support one, support SAML — that is what enterprise procurement asks for. The OASIS SAML technical overview at docs.oasis-open.org/security/saml/v2.0 is the canonical specification.
The IdP is whatever system the customer uses to manage employee identities. Your job is not to pick an IdP; it is to interoperate with whichever one the customer already has. The list is short.
| Identity Provider | Typical customer | Notes |
|---|---|---|
| Okta | Mid-market and enterprise | The dominant standalone IdP. SAML is first-class. |
| Microsoft Entra ID | Microsoft 365 shops | Formerly Azure Active Directory. Default IdP for any company on Microsoft 365. Supports SAML and OIDC. |
| Google Workspace | Smaller orgs and tech-forward companies | Strong OIDC support. SAML available. Often the IdP of choice for series-A startups. |
| Auth0 | Mid-market | Both an IdP and an SSO vendor. Some customers use Auth0 to broker SSO into other applications. |
| OneLogin | Mid-market | Smaller market share than Okta but functionally similar. |
| JumpCloud | Smaller IT-managed organizations | Combines IdP with device management. |
| PingIdentity | Large enterprise | Common in regulated industries; rarely encountered by early-stage SaaS. |
SAML defines two ways an SSO sign-in can begin, and both are common in practice.
SP-initiated (Service Provider initiated): the user lands on your app, clicks “Sign in with SSO,” you redirect them to their IdP, they authenticate there, and the IdP POSTs an assertion back to your app. This is the cleaner UX for users who arrive on your site directly.
IdP-initiated: the user lands first on their company's IdP dashboard (the Okta or Entra app launcher), clicks the icon for your app, and the IdP POSTs an assertion to your app with no prior request. The user appears in your app already authenticated. Many enterprise IT teams expect this flow because it matches how their internal app launchers work.
Supporting both is standard for any production SSO implementation. The IdP-initiated flow has a few security subtleties around CSRF and replay that you have to handle correctly — another reason most teams use a vendor rather than rolling their own.
You technically can build SAML support from scratch. Open-source libraries exist; the protocol is documented; the XML signing requirements are knowable. The path is also miserable. SAML implementations are notoriously edge-case-prone, with quirks across IdPs, signature canonicalization issues, certificate rotation, and the IdP-initiated CSRF subtleties mentioned above. A clean SAML implementation typically takes a senior engineer two to four weeks, and the security review afterward takes another week.
The vendor alternative is to delegate SSO to a managed auth platform that handles SAML, OIDC, and the metadata exchange UX with the customer's IT admin. The 2026 generation of vendors makes this economical, even for solo founders.
The four most relevant options for a solo SaaS founder shopping for SSO:
WorkOS is purpose-built for adding SSO to existing apps. Its pricing model is the headline: $0 per connection up to 1 million MAU, with the SSO product itself effectively free at the scale most solo SaaS founders operate at. The API surface is small and clean — you get a single SSO endpoint that abstracts away whether the customer is on Okta, Entra, or Google Workspace. Their documentation is widely considered the best in the category. WorkOS also offers SCIM for user provisioning at the same price.
Clerk includes SAML SSO in its Enterprise tier. If you are already using Clerk for your standard auth (email + password, social, magic links) and an enterprise prospect arrives, upgrading to Enterprise unlocks SAML without changing your auth code. The trade-off is that Clerk Enterprise is custom-priced and typically meaningfully more expensive than WorkOS for SSO alone. Our Clerk pricing explained guide walks through the numbers.
Auth0 supports SAML in its Essentials tier and up. Auth0 was the dominant developer-focused auth vendor for the better part of a decade and is now owned by Okta. It is feature-complete and well-documented; pricing climbs steeply at scale, particularly with B2B add-ons. Our breakdown of Clerk vs Auth0 covers the comparison.
Stytch offers SSO as a pay-as-you-go API alongside its other auth primitives. Less opinionated than Clerk; closer in spirit to WorkOS. Reasonable choice if you already use Stytch for passwordless auth and want SSO from the same vendor.
For years, large SaaS vendors charged dramatically more for plans that included SSO — often 3x to 10x the price of the next tier down, with SSO as the only meaningful feature unlock. Slack, Notion, and many others gated SSO behind “Enterprise” plans that priced out smaller customers. The community-run sso.tax documents the markup vendor-by-vendor.
The argument for the SSO tax: SSO is a high-touch, IT-team-driven sale, and the support burden justifies premium pricing. The argument against: SSO is a security feature, and gating security behind enterprise pricing perversely incentivizes smaller companies to skip the secure option. The WorkOS / Clerk / Stytch generation of vendors built their pricing around the second argument: SSO is included or cheap, and enterprise pricing is justified by other features (audit logs, dedicated support, custom contracts) rather than by SSO itself.
For a solo SaaS founder making pricing decisions, the lesson is simple: do not stack a 5x markup on your SSO tier. The market has shifted, and customers know the wholesale cost of SSO is low. Pricing SSO at a modest premium — or making it a function of seat count rather than a flat add-on — is better received than a 10x enterprise jump.
SSO handles authentication: who is allowed to sign in. SCIM (System for Cross-domain Identity Management) handles provisioning: which user accounts exist in your application, and what groups they belong to. Together they form the “enterprise identity” pair.
The flow: when an IT admin in the customer's IdP creates a new employee, SCIM pushes that user into your application automatically. When the employee is terminated, SCIM removes them. Without SCIM, the customer's IT team has to manually add and remove users in your app every time someone joins or leaves — a workload that grows linearly with their headcount.
The SCIM specification is at RFC 7644. As with SAML, you can implement it yourself, but the same vendors that solve SSO usually solve SCIM in the same product. WorkOS Directory Sync, Clerk Enterprise, and Auth0's SCIM connector all bundle them. Most enterprise customers ask for both; quoting an SSO deal without including SCIM provisioning is increasingly a deal-blocker on its own.
Compress all of the above into a few lines of practical advice.
SSO is not always the right addition. A few situations where it is genuinely premature:
SSO is also not the same as SOC 2 compliance. They often arrive together in customer requests, but they are independent: SSO is a technical feature; SOC 2 is a compliance attestation. Our breakdown of SOC 2 compliance covers the auditor-side story.
Single Sign-On is the authentication pattern that lets a user sign in once at a trusted Identity Provider and access multiple applications without further credentials. For solo SaaS founders, it shifts from “a fancy enterprise feature” to “a deal-blocker” the day you start selling above $10K ACV. Build it when a real customer asks; use a vendor like WorkOS or Clerk; price it fairly; bundle SCIM with it. Do not spend a quarter rolling your own SAML library. The cost of buying SSO from a modern vendor is meaningfully less than the cost of one lost enterprise deal.
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