Glean AI vs ZenSearch: Enterprise AI Search Compared
Both Glean and ZenSearch are enterprise AI search platforms that connect internal data sources and provide AI-powered answers. Here is how they compare on deployment, features, and security.
Summary
Choose ZenSearch if you need:
- True on-premise deployment with full infrastructure control
- Free Lite self-host edition for evaluation
- NL-to-SQL queries against enterprise databases
- Comprehensive AI guardrails (injection, PII, hallucination)
- Flexibility to bring your own AI models
- Air-gapped or private cloud deployment
Choose Glean if you need:
- 100+ pre-built connectors (vs ZenSearch's 17+)
- Established enterprise brand with SOC 2 Type II
- Mature integrations with Google Workspace and Microsoft 365
- An organization already using Glean's ecosystem
Search & AI Capabilities
| Feature | ZenSearch | Glean |
|---|---|---|
Hybrid search (dense + sparse) | ||
Cross-encoder reranking | ||
Vector search | ||
Faceted search & filtering | ||
NL-to-SQL database queries Query PostgreSQL, MySQL, ClickHouse, SQL Server with natural language | ||
AI agents with tool calling | ||
Custom agent builder | Limited | |
Multi-agent delegation Agents hand off subtasks to specialist agents in the same team via discover_agents + delegate_to_agent. Depth-limited at 2 levels | ||
Self-improving procedural memory Hermes-inspired skill loop: successful multi-tool sessions are distilled into reusable workflows that future runs progressively disclose and reuse | ||
Observational memory (long-conversation compression) LLM-based observer extracts key findings into a cacheable system-prompt prefix — 80%+ token compression on 50+ message conversations | ||
Agent memory & checkpointing Three-layer memory: persistent facts/preferences, observational compression, procedural workflows | ||
Retrieval augmented generation | ||
Cited answers with sources | ||
Guardrails (hallucination, PII, injection) | Partial | |
Answer confidence scoring | ||
Slack / Teams Surfaces | Slack, Teams, Chrome | Slack integration |
AI Governance (Risk Tiers) | T0-T5 policy engine | Basic controls |
Cross-Surface Approvals | Slack, Teams, and web | Not available |
Scheduled Automations | Cron + event triggers | Not available |
Deployment Options
| Feature | ZenSearch | Glean |
|---|---|---|
Cloud (SaaS) | ||
True on-premise deployment Glean offers 'customer-hosted cloud' (managed by Glean in your VPC) — not true on-premise | ||
Air-gapped deployment | ||
Docker & Kubernetes | ||
Bring your own LLM Use OpenAI, Anthropic, Cohere, Groq, OpenRouter, Ollama, or any OpenAI-compatible endpoint | ||
Single-tenant infrastructure | Enterprise only | |
Data residency control | Limited |
Data Connectors
| Feature | ZenSearch | Glean |
|---|---|---|
Confluence | ||
Slack | ||
GitHub | ||
Google Drive | ||
SharePoint | ||
Jira | ||
Notion | ||
Salesforce | ||
SAP | ||
HubSpot | ||
PostgreSQL / MySQL / SQL Server NL-to-SQL with schema discovery | ||
ClickHouse | ||
S3 / Azure Blob | ||
Web Crawler | ||
Total connectors | 17+ | 100+ |
Security & Compliance
| Feature | ZenSearch | Glean |
|---|---|---|
SOC 2 Type II | In progress | |
Document-level RBAC | ||
Permission-aware search | ||
End-to-end encryption | ||
Audit logging | ||
HIPAA eligible | On-premise | Enterprise |
Input/output guardrails | Partial | |
Prompt injection detection | ||
PII detection & filtering |
Where ZenSearch stands apart
Key areas where ZenSearch offers capabilities that Glean does not.
True On-Premise Deployment
ZenSearchZenSearch deploys directly on your infrastructure with Docker and Kubernetes. Air-gapped environments fully supported. Your data never leaves your network.
True On-Premise Deployment
GleanGlean offers 'customer-hosted cloud' — Glean manages the software in your cloud VPC, but you don't control the deployment. Not true on-premise.
NL-to-SQL Database Queries
ZenSearchQuery PostgreSQL, MySQL, ClickHouse, and SQL Server databases using natural language. Schema discovery, read-only execution, and query validation built in.
NL-to-SQL Database Queries
GleanGlean does not support direct database querying. Database content must be ingested through file-based connectors or custom integrations.
Comprehensive AI Guardrails
ZenSearchInput and output guardrails including prompt injection detection, PII filtering, hallucination detection (lexical, semantic, hybrid), and toxicity filtering. Per-tenant configuration.
Comprehensive AI Guardrails
GleanGlean provides content moderation but lacks configurable guardrails for prompt injection, PII detection, and hallucination scoring.
Bring Your Own Models
ZenSearchUse ZenSearch's managed models or bring your own. Supports OpenAI, Anthropic, Cohere, Groq, OpenRouter, Ollama, and any OpenAI-compatible endpoint via the Model Gateway.
Bring Your Own Models
GleanGlean uses its own proprietary models. Limited flexibility to use third-party or self-hosted models.
On-premise deployment: a closer look
Glean advertises “customer-hosted” deployment. Here is what that means compared to ZenSearch’s true on-premise deployment.
ZenSearch On-Premise
- Deploy with Docker and Kubernetes on any infrastructure
- Full control over compute, storage, and networking
- Air-gapped deployment — no internet connection required
- Bring your own LLM (Ollama, vLLM, or any OpenAI-compatible API)
- You manage updates on your schedule
- No vendor access to your infrastructure
- Data never leaves your network
Glean Customer-Hosted Cloud
- •Deployed in your cloud VPC (AWS, GCP, Azure)
- •Glean manages the software and infrastructure within your VPC
- •Requires internet connectivity for Glean management plane
- •Uses Glean's proprietary AI models
- •Updates managed by Glean on their schedule
- •Glean has operational access to the deployment
- •Data stays in your VPC but Glean has management access
Ready to try ZenSearch?
Evaluate the free Lite self-host edition or contact us for an enterprise deployment shaped to your environment.
See how ZenSearch compares to other enterprise search platforms.