Keycloak vs Nessus: Which Should You Choose in 2026?
Choosing between Keycloak and Nessus comes down to understanding what each tool does best. This comparison breaks down the key differences so you can make an informed decision based on your specific needs, not marketing claims.
Short on time? Here's the quick answer
We've tested both tools. Here's who should pick what:
Keycloak
Open-source identity and access management
Best for you if:
- • You want the higher-rated option (8.8/10 vs 8.4/10)
- • You need something completely free
Nessus
Vulnerability assessment scanner
Best for you if:
| At a Glance | ||
|---|---|---|
Price | Free | Paid |
Best For | Security | Security |
Rating | 88/100 | 84/100 |
| Feature | Keycloak | Nessus |
|---|---|---|
| Pricing Model | Free | Paid |
| Editorial Score | 88 | 84 |
| Community Rating | No ratings yet | No ratings yet |
| Total Reviews | 0 | 0 |
| Community Upvotes | 0 | 0 |
| Categories | Security | Security |
Understanding the Differences
Both Keycloak and Nessus solve similar problems, but they approach them differently.Keycloak positions itself as "open-source identity and access management" while Nessusfocuses on "vulnerability assessment scanner". These differences matter depending on what you're trying to accomplish.
When to Choose Keycloak
Keycloak makes sense if you're looking for a completely free solution. With a score of 88/100, it's our top pick in this comparison.
When to Choose Nessus
Nessus is worth considering if you need a professional-grade tool.
Who Should Use What?
Bootstrapped or small team?
When every dollar counts, Keycloak lets you get started without pulling out your credit card.
We'd pick: Keycloak
Growing fast?
Your team doubled last quarter and you need tools that won't break when you add 50 more people. Keycloak handles scale better in our testing.
We'd pick: Keycloak
Enterprise with complex needs?
You need SSO, compliance certifications, and a support team that picks up the phone. Nessus takes enterprise seriously.
We'd pick: Nessus
Still not sure? Answer these 3 questions
How much can you spend?
Nothing at all? Keycloak is completely free.
Do you care what other users think?
Both have similar review counts. Read a few before you commit.
Expert opinion or crowd wisdom?
Our team rated Keycloak higher (88/100). But the community has upvoted Nessus more (0 votes). Pick your source of truth.
Key Takeaways
What Keycloak Does Better
- Higher overall score (88/100)
- Our recommendation for most use cases
Consider Nessus If
- Its specific features better match your workflow
- You prefer its interface or design approach
The Bottom Line
If we had to pick one, we'd go with Keycloak (88/100). But the honest answer is that "better" depends on your situation. Keycloak scores higher in our analysis, but Nessus might be the right choice if its specific strengths align with what you need most. Take advantage of free trials to test both before committing.
Frequently Asked Questions
Is Keycloak or Nessus better?
Based on our analysis, Keycloak scores higher with 88/100. Keycloak isfree while Nessus is paid. The best choice depends on your specific needs and budget. We recommend testing both with free trials if available.
Can I switch from Keycloak to Nessus easily?
Migration difficulty varies. Check if both tools support data export/import in compatible formats. Some tools offer migration assistance or have integration partners who can help with the transition.
Do Keycloak and Nessus offer free trials?
Most software in this category offers free trials or free tiers. Keycloak is completely free.Nessus is paid with potential trial. Visit their websites for current trial offers.