Identity Provider (IdP) Mode

In SAML 2.0 (OASIS XML-based SSO standard), an Identity Provider authenticates users and issues signed XML assertions that Service Providers trust. Configure LumoAuth as a SAML IdP to provide SSO to applications like Salesforce, Box, Slack, AWS Console, or custom enterprise apps.

SP-Initiated SSO Flow

In the most common flow, the user starts at the SP application, which redirects to LumoAuth for authentication.

IdP Metadata Endpoint

GET /orgs/\{orgId\}/saml/idp/metadata

Returns the SAML IdP metadata XML document. Provide this URL to SP applications to configure SAML SSO automatically.

Example Request

curl https://app.lumoauth.dev/orgs/acme-corp/saml/idp/metadata

Response

MIICo...
                
            
        
        
        
            urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress
        
        
            urn:oasis:names:tc:SAML:2.0:nameid-format:persistent

Single Sign-On Endpoint

GET/POST /orgs/\{orgId\}/saml/idp/sso

Receives SAML AuthnRequests from Service Providers. Supports both HTTP-Redirect and HTTP-POST bindings.

HTTP-Redirect Binding (GET)

Parameter	Required	Description
SAMLRequest	Yes	Base64 + DEFLATE encoded AuthnRequest
RelayState	No	Opaque state preserved through SSO
SigAlg	If signed	Signature algorithm
Signature	If signed	Request signature

HTTP-POST Binding (POST)

Parameter	Required	Description
SAMLRequest	Yes	Base64 encoded AuthnRequest
RelayState	No	Opaque state preserved through SSO

Processing Flow

1. Decode and parse the AuthnRequest
2. Validate the request (signature if required)
3. If user is logged in, generate SAML Response immediately
4. If user is not logged in, redirect to login page
5. After authentication, generate signed SAML Response
6. POST the Response to SP's ACS URL

SAML Response Structure

LumoAuth generates signed SAML Responses containing user assertions:

https://app.lumoauth.dev/orgs/acme-corp/saml/idp/metadata
    
    ...
    
    
        
    
    
    
        https://app.lumoauth.dev/orgs/acme-corp/saml/idp/metadata
        
        
            
                user@example.com
            
            
                
            
        
        
        
            
                https://sp.example.com
            
        
        
        
            
                user@example.com
            
            
                John
            
            
                Doe
            
        
        
        
            
                
                    urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport

Configuration Guide

Step 1: Add the SP Application

1. Navigate to SAML Apps in your organization portal
2. Click New SAML App
3. Enter the SP configuration:

• Name: Application display name
• Entity ID: SP's unique identifier
• ACS URL: Where to send SAML Responses

4. Configure NameID format and attributes
5. Save the configuration

Step 2: Configure the SP Application

Provide your IdP metadata to the SP application. Most SPs accept a metadata URL:

{
    "User.Email": "email",
    "User.FirstName": "givenName",
    "User.LastName": "sn",
    "User.Department": "department",
    "User.EmployeeNumber": "employeeNumber"
}

Popular SP Configuration

Salesforce

Entity ID	https://saml.salesforce.com
ACS URL	https://login.salesforce.com/...
NameID	emailAddress (Federation ID)

Box

Entity ID	box.net
ACS URL	https://app.box.com/saml/...
NameID	emailAddress

Slack

Entity ID	https://slack.com
ACS URL	https://your-workspace.slack.com/sso/saml
NameID	emailAddress

Certificate Management

LumoAuth generates X.509 certificates automatically for each organization:

• RSA 2048-bit keys with SHA-256 signatures
• Default validity: 3 years
• Automatic generation on first use
• Custom certificate import available

Certificate Rotation

Plan certificate rotation in advance. LumoAuth can publish multiple certificates at once so SP applications can switch over without downtime.