Okta + Slack integration
Set up Okta as the identity provider for Slack via SAML + SCIM — with SCIM provisioning enabled on Slack Enterprise Grid.
- Okta admin + Slack workspace owner role
- Slack Enterprise Grid plan for SCIM (Business+ for SSO only)
- A test user in both directories
1. Create a new SAML 2.0 application in Okta
In the Okta admin console, create a new SAML 2.0 application. Choose "Web Application" type. Note the placeholders for ACS URL + Entity ID — you'll get these from Slack in step 3.
2. Get the SAML metadata URL from Okta
Okta exposes the IdP metadata at a stable URL. Copy this URL — you'll paste it into Slack's SSO configuration. Alternatively, download the metadata XML if Slack doesn't support URL-based metadata.
3. Configure SSO in Slack
In Slack's admin → security → SSO settings, paste the Okta metadata URL (or upload the XML). Slack will display the ACS URL + Entity ID it expects — copy these.
4. Return to Okta + complete the SAML app config
Paste Slack's ACS URL into the Okta app's Single Sign-On URL field. Paste the Entity ID into the Audience URI field. Set the NameID format to EmailAddress (or persistent if Slack expects that).
5. Configure attribute mapping
Map the attributes the SP expects (see the Attribute Mapping section below). At minimum, email is required. Most apps also expect firstName + lastName.
6. Assign users + groups
In Okta, assign the SAML app to users or groups that should have access. Test with a pilot group before broad rollout.
7. Test end-to-end
Sign in to Slack via the IdP-initiated link (from Okta dashboard) AND via SP-initiated (direct Slack login URL). Both should work. Check the SAML Tracer browser extension or SAML decoder to inspect the assertion if anything fails.
What flows from where.
| Source (Okta) | Target (Slack) | Note |
|---|---|---|
| user.email | Required for matching | |
| user.firstName | givenName | — |
| user.lastName | familyName | — |
| user.title | title | — |
- Clock skew: Okta and Slack clocks must be within ~5 minutes. NTP-sync both. SAML's NotBefore + NotOnOrAfter are strict.
- NameID format mismatches are the most common failure. Slack typically wants EmailAddress; Okta defaults vary. Mismatch → cryptic "invalid assertion" errors.
- Just-in-time (JIT) provisioning vs SCIM: many apps support both. SAML JIT creates the user on first SSO; SCIM creates them ahead of time. Pick one — both can cause attribute drift.
- Audience restriction: Slack's expected Audience URI must match exactly what the IdP sends. Trailing slashes + protocol (http vs https) matter.
- Signed Response vs signed Assertion: many SPs require the Assertion to be signed (not just the Response envelope). Check the SP's docs.
- SCIM is only available on Enterprise Grid — Business+ supports SAML SSO but manual user lifecycle.
- Slack guest users are a separate model — SCIM doesn't manage guests by default.
- Channel membership is independent of SSO. SCIM creates the user; channel join is a separate workflow.
- IdP-initiated SSO works (sign in from the IdP dashboard)
- SP-initiated SSO works (visit Slack directly + get redirected to IdP)
- User attributes flow through correctly (email, name, groups)
- Logout (single logout if supported) works as expected
- Step-up MFA fires when policy requires it
- Unauthorized users (not assigned to the app) get a clean denied message
- Capture a successful SAML response and inspect it (use the SAML decoder tool)
For the latest vendor-side configuration changes, refer to:
Slack SAML / SCIM integration →