Glean vs Sierra Comparison
Compare Glean vs Sierra features, pricing, and more.
Last updated: November 2026
Glean
7/10
Glean is an enterprise work AI platform that searches company apps with permission controls, answers questions with citations, and runs agents for large organizations.
Sierra
7.4/10
Sierra is an enterprise conversational AI platform that builds and runs customer service agents across chat, voice, SMS, WhatsApp and email.
Feature-by-Feature Comparison
| Feature | | |
|---|---|---|
| Scores | ||
| Overall Rating | 7/10 | 7.4/10 |
| Analytics | 6/10 | 8/10 |
| Cost | 2/10 | 2/10 |
| Customization | 7/10 | 9/10 |
| Ease of Use | 7/10 | 7/10 |
| Integration | 10/10 | 8/10 |
| Output Quality | 8/10 | 9/10 |
| Scalability | 9/10 | 9/10 |
| Security | 9/10 | 9/10 |
| Support | 6/10 | 8/10 |
| Pricing | ||
| Free plan | No | No |
| Cheapest paid plan | Contact for pricing | Contact for pricing |
| Estimated cost for 10 users | Contact for pricing | Contact for pricing |
| Features | ||
| AI Agents | ||
| Chatbots | ||
| Enterprise Controls | ||
| Knowledge Base Search | ||
| Text Generation | ||
| Workflow Automation | ||
| API Access | Not listed | |
| Voice and Audio | Not listed | |
Which One Should You Choose?
Why choose Glean
- Higher Integration score (10/10 vs 8/10)
Why choose Sierra
- Higher Analytics score (8/10 vs 6/10)
- Higher Customization score (9/10 vs 7/10)
Pros & Cons
Glean
Pros
- Glean lists more than 275 connected apps, so employees can search Slack, Drive, Jira, Salesforce and other tools from one place.
- Search results follow each source system's access controls, which lowers the risk of exposing data to the wrong people.
- AI answers include citations that link back to the source documents, so users can check them.
- Developers get Client and Indexing APIs, a Web SDK, agent toolkits and an MCP server for building on Glean.
- Its compliance certifications include SOC 2 Type II, ISO 27001, ISO 42001 and HIPAA.
Cons
- Glean publishes no prices; third-party reports put seats at about 50 dollars or more per user per month with minimums of roughly 100 seats.
- There is no free trial, and some reports describe proofs of concept as paid.
- Setup, permission configuration and relevance tuning take significant work from IT teams.
- Reviewers report renewal increases of about 3 to 12 percent a year and possible extra fees for premium support.
- Some users report answers that do not fully match the source data, and say the ranking is hard to customize.
Sierra
Pros
- Outcome-based billing means customers usually pay only for resolved conversations or other agreed results, not for each seat.
- Three build options cover both CX teams and engineers: the no-code Agent Studio, the code-first Agent SDK, and Ghostwriter for building agents from SOPs.
- One agent runs across chat, voice, SMS, WhatsApp, email and ChatGPT, keeping context between channels.
- Its list of compliance attestations is broad, covering SOC 2, ISO 27001, ISO 42001, HIPAA, PCI DSS and FedRAMP.
- It has a strong roster of enterprise customers, including SiriusXM, ADT, Rocket Mortgage and SoFi.
Cons
- There is no public pricing, and competitor estimates put annual contracts at about $150,000 or more.
- There is no self-serve or trial tier, so small teams cannot try it on their own.
- Implementation is largely vendor-led, which can make customers depend on Sierra's team for changes.
- There are few public reviews (7 on Gartner Peer Insights) to verify claims against.
- Some reviewers say voice quality still falls short of human level, and that complex telephony setups depend on how far the integration goes.
Not sold on either?
Frequently Asked Questions
Sierra scores higher on our AI Software criteria: 7.4/10 against 7/10 for Glean. The largest gap is in Analytics: 6/10 for Glean and 8/10 for Sierra.
No, neither Glean nor Sierra lists a free plan.
