What is SSO?
SSO, Single Sign-On, is an authentication scheme that allows a user to log in once with one set of credentials and access multiple applications without re-entering credentials for each. The user authenticates to a central identity provider (Google Workspace, Microsoft 365, Okta, OneLogin); the identity provider issues tokens that other applications trust.
The user experience is seamless. After morning login to Google Workspace, the user clicks CRM, accounting tool, project management, and each opens without password prompt. Behind the scenes, each application redirects to the identity provider, receives a token, and grants access.
Protocols powering SSO include SAML (Security Assertion Markup Language, dominant in enterprise), OAuth 2.0 (delegated authorisation, modern web), and OpenID Connect (authentication layer on OAuth 2.0, increasingly common). SAML uses signed XML; OIDC uses signed JSON tokens.
Why SSO matters for solar businesses
For Indian solar EPCs using multiple SaaS tools (CRM, accounting, payments, WhatsApp Business, design software), SSO eliminates password fatigue. Without SSO, users maintain separate passwords for each tool, leading to password reuse, weak passwords, or written-down credentials.
For security, SSO centralises authentication policies. MFA enforced at the identity provider applies to all apps. Strong password requirements apply everywhere. Offboarding (when an employee leaves) revokes one identity and removes access across all apps in minutes.
For DPDP compliance, SSO supports faster handling of data subject rights and access revocation. Centralised identity logs provide audit trails. Quality SSO implementation supports compliance discipline.
How SSO operates
- User logs into identity provider. Once per day or session.
- Identity provider authenticates. Password + MFA typically.
- User opens application. Application redirects to IDP.
- IDP checks active session. Issues token.
- Application validates token. Grants access.
- User sees app. No password prompt.
- Token expiry. Refresh or re-authenticate.
- Logout from IDP. Cascades to all apps.
- Audit logging. Centralised security events.
- Offboarding. Disable IDP account; access revoked.
Benefits of SSO
- User experience. One login for many apps.
- Security. Centralised MFA and policies.
- Onboarding speed. Provision once.
- Offboarding speed. Revoke once.
- Audit logging. Centralised events.
- Password reuse reduction. Fewer passwords overall.
- DPDP support. Easier data subject handling.
Limitations and challenges
Single point of failure. IDP outage affects all apps.
App SSO support required. Not all SaaS support SSO.
Setup complexity. SAML or OIDC integration effort.
Cost. Enterprise SSO providers expensive at scale.
Identity provider dependency. Vendor lock-in.
Multi-tenant edge cases. User identity across customers.
SSO adoption patterns for Indian solar SaaS
| Customer segment | SSO pattern |
|---|---|
| Small EPC (under 20 users) | Google Workspace social login |
| Mid-size EPC (20 to 100 users) | Google Workspace or Microsoft 365 SSO |
| Large EPC (100+ users) | Dedicated SSO provider (Okta, Azure AD) |
| SECI bidders and PSU partners | Enterprise SSO with SAML |
| Solar SaaS vendor side | Support SAML, OIDC, social login |
| Customer portal (residential) | Social login (Google, Apple) |
Quick facts
| Full form | Single Sign-On |
|---|---|
| Protocols | SAML, OAuth 2.0, OpenID Connect |
| Common providers | Google Workspace, Microsoft 365, Okta |
| Benefits | UX, security, audit, fast offboarding |
| Related | OAuth, MFA, identity management |
| DPDP relevance | Supports data subject rights handling |
| Procurement | Enterprise customers increasingly require |
Common mistakes about SSO
- No MFA on IDP. Single password becomes single weak point.
- No offboarding playbook. Departing user retains access.
- No SSO support in SaaS. Procurement disqualification.
- Treating SSO as enterprise-only. SMB benefits too.
- Confusing SSO with password manager. Different solutions.
- No failover plan. IDP outage paralyses operations.
- Skipping audit logging. Security blind.
- Mixing identity providers. Fragmented experience.
Key takeaways
- SSO is one login for many applications.
- Powered by SAML, OAuth 2.0, OpenID Connect.
- Improves UX, security, and operational discipline.
- Enterprise SSO via Okta, Microsoft, Google.
- SMB pattern: Google Workspace SSO or social login.
- Supports DPDP compliance and audit.
- Increasingly required in B2B SaaS procurement.
Frequently Asked Questions
What is SSO?
SSO (Single Sign-On) is an authentication scheme that allows a user to log in once with one set of credentials and access multiple applications without re-entering credentials. For Indian solar EPCs using multiple SaaS tools (CRM, accounting, WhatsApp platform), SSO eliminates password fatigue and improves security.
How does SSO work?
User logs into the SSO identity provider (Google Workspace, Microsoft 365, Okta). The identity provider issues a token that other applications trust. When the user accesses an application, the application redirects to the SSO provider, receives the token, and grants access without password entry.
What is the difference between SSO and OAuth?
SSO is the user experience: one login for many apps. OAuth is the protocol that often powers SSO. SSO is the 'what'; OAuth is the 'how'. SAML and OpenID Connect are other protocols that power SSO.
What is SAML?
SAML (Security Assertion Markup Language) is the older protocol for enterprise SSO. Identity provider sends signed XML assertions to applications. SAML is dominant in enterprise SSO; OAuth/OpenID Connect is more common in B2C and modern apps.
What is OpenID Connect?
OpenID Connect (OIDC) is a modern authentication protocol built on top of OAuth 2.0. While OAuth handles authorisation, OIDC adds authentication: it verifies who the user is. Most modern SSO implementations use OIDC.
Why is SSO important for solar EPCs?
Solar EPCs use multiple SaaS tools (CRM, accounting, payments, WhatsApp). Without SSO, each user maintains separate passwords, leading to password reuse, weak passwords, or written-down passwords. SSO centralises authentication, improves security, and reduces friction.
Is SSO mainly enterprise?
Enterprise has driven SSO adoption (Google Workspace, Microsoft 365, Okta dominate). For SMB, social login ('Sign in with Google') provides similar benefits. For Indian solar SMB EPCs, Google Workspace SSO is a common pattern.
Does SSO require all apps to support it?
Yes. Apps must integrate with the SSO provider via SAML, OIDC, or OAuth. SaaS that does not support SSO breaks the unified experience. Enterprise customers increasingly require SSO support in procurement.
What are SSO security benefits?
Centralised authentication (one strong policy), MFA enforcement (multi-factor across all apps), faster offboarding (revoke one identity, remove access everywhere), audit logging (centralised), reduced password reuse risk.
What is the risk of SSO?
Single point of failure: if the SSO provider is breached or down, all apps are affected. Quality SSO implementations use MFA and have failover procedures. Application-level credentials may still be maintained as backup.
Is SSO required for DPDP?
Not directly mandated, but quality DPDP practice favours centralised identity management. Easier to support data subject rights (access, deletion) when identity is unified. Faster off-boarding and access revocation also support compliance.
How is SSO set up?
Configure identity provider (Google, Microsoft, Okta). Each application is integrated (SAML metadata exchange or OAuth/OIDC client setup). Users provision in identity provider; applications consume identity. Quality SaaS publish SSO setup documentation.
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- SAML 2.0 specifications.
- OpenID Connect specifications.
- Google Workspace SSO documentation.
- Microsoft Entra ID (formerly Azure AD) documentation.
- Okta SSO architecture papers.
- OWASP authentication guidelines.
- NASSCOM SaaS security reports.
Written by QuickEstimate Editorial, QuickEstimate Editorial (Surat).
Last updated: 4 June 2026.