Report: Glean vs. ChatGPT Business for Enterprise Knowledge & Search

Overview

This report compares Glean and ChatGPT Business/Enterprise for enterprise knowledge management, internal search, and company-wide Q&A. It focuses on real capabilities, security posture, and where each fits best, based on independent reviews, vendor docs, and third‑party analyses.

Quick Comparison

Capability / Concern	Glean (Work AI / Enterprise Search)	ChatGPT Business / Enterprise
Primary strength	Unified enterprise search & RAG across SaaS apps and internal content Glean site	General‑purpose reasoning & generation with new "company knowledge" feature OpenAI
Data sources	Deep connectors to tools like Google Workspace, Microsoft 365, Slack, Jira, Salesforce, Confluence, etc. AWS	File uploads, connectors and integrations; still emerging as an enterprise search layer Varonis
Core UX	Google‑like search + AI answers + work app actions in one interface Glean	Chat interface; prompts over models, with optional company knowledge and tools OpenAI
Knowledge grounding	Strong emphasis on permissions‑aware, hybrid search + RAG grounded in indexed enterprise content Glean blog	Answers can be grounded in uploaded / indexed company knowledge, but still fundamentally an LLM that can hallucinate OpenAI help
Security model	Fine‑grained permissions, SSO, SCIM, and index‑level access control; has public bug bounty Bugcrowd and enterprise infosec content	Enterprise SKUs offer data‑use controls, SOC2/ISO, and tenant isolation, but there are many warnings about mis‑config and shadow AI use IBM
Recognitions & adoption	Gartner Peer Insights Customers’ Choice 2024 for Insight Engines; 4.5+/5 scores and case studies with Databricks, Super.com, others Glean	OpenAI reports 1M+ businesses using ChatGPT; very broad cross‑industry adoption for knowledge work OpenAI
Best for	Companies that want a system of record for knowledge search across all apps, with low hallucination and strong access control	Companies that want flexible AI assistants for drafting, coding, analysis, and Q&A, including over internal docs, where general reasoning is as important as search
Main criticisms	Cost/complexity at large scale; search‑specific; security critics argue it’s not as locked down as some competitors Lucidworks	Hallucinations, security/data‑leak risk if misused; not a full KM system; requires governance and architecture around it CSA

What Glean Actually Is

Glean positions itself as a “Work AI" / enterprise search platform that:

Indexes content across SaaS apps (Docs, email, tickets, code, wikis, CRM, etc.)
Applies permissions‑aware search so users only see what they already have access to Glean security
Uses hybrid search (lexical + vector) and RAG to generate answers with citations Dev article
Provides an AI assistant that can answer questions, surface people, and even trigger workflow actions in some tools Slite review

Glean’s own content and case studies emphasize outcomes like reduced time to find information, faster onboarding, and fewer knowledge silos Glean guide Super.com case.

Evidence of Effectiveness

Independent & third‑party evidence:

Customer stories from companies like Databricks and Super.com describe measurable improvements in knowledge discovery and productivity after rolling out Glean across their app stack Databricks story Super.com story.
A Forrester TEI study (sponsored, but detailed) reports ROI and time‑savings from Glean’s Work AI platform in enterprise deployments Forrester TEI.
G2 and Gartner reviews show 4.5–4.8/5 ratings in the Insight Engines category and include comments about relevance, speed, and ease of rollout compared to legacy search Glean.

How does Glean really compare to ChatGPT Enterprise for internal knowledge?

Where Glean Shines

Unified search over everything: For employees who live across Slack, email, Confluence, Notion, Jira, etc., Glean provides one search bar that respects each system’s ACLs AWS Marketplace.
Permissions‑aware RAG: Answers are assembled from documents the user can access, and many implementations show inline citations to the source documents, which reduces blind trust and hallucination risk Glean RAG blog.
Workflows & agents: Glean is expanding from search to AI agents that can help with procedure drafting and report generation based on internal knowledge Glean agents.
Enterprise‑grade packaging: SSO, SCIM, DLP integrations, logging, and a Bugcrowd program show that security is a first‑class concern Bugcrowd.

How does Glean’s security posture compare to other search vendors like Lucidworks?

Glean Limitations & Criticisms

Security & risk debates
Competitors and security vendors argue that putting “ChatGPT for work” in front of all SaaS data must be scrutinized:
- A Lucidworks comparison page explicitly claims “Glean doesn’t have enterprise‑grade security” and highlights gaps around fine‑grained control and observability relative to its own platform Lucidworks vs Glean.
- DoControl and others warn about centralizing access to sensitive data, stressing the need for strict identity, permissions, and DLP controls when adopting Glean DoControl.
These critiques are partly competitive marketing, but they underscore that Glean increases the blast radius if identity or permissioning is mis‑configured.
Not a general AI platform
Glean is very strong at retrieval & knowledge search. It is not a general‑purpose AI assistant in the same sense as ChatGPT; content creation, coding, and analytics use cases are secondary and usually handled by other tools that Glean can link to.
Implementation effort and change management
Multiple reviews mention the work needed to connect systems, tune relevance, manage groups, and drive adoption. For small teams, this overhead can feel heavy compared with “just use ChatGPT” eesel guide.
Pricing and scope
Being an enterprise platform, Glean tends to be more expensive and contract‑driven than generic chatbots. Some evaluations list cost as a deciding factor in choosing lighter‑weight or open‑source alternatives Gartner alternatives.

What are the common implementation pitfalls when rolling out Glean?

What ChatGPT Business / Enterprise Actually Is

OpenAI’s ChatGPT Business/Enterprise is a set of SKUs that provide:

Access to advanced GPT models (e.g., GPT‑4.1, GPT‑5.x era) with higher rate limits and admin controls
Company Knowledge: the ability to index internal documents and data and let users query it in ChatGPT OpenAI
Tenant‑level security & privacy commitments (no training on your data, SOC2/ISO controls on enterprise plans) OpenAI Business
Management features like SSO, domain verification, and admin analytics

It is fundamentally an LLM assistant with optional knowledge retrieval and tools layered on top – not a dedicated search engine.

Evidence of Effectiveness for Internal Q&A

OpenAI cites 1 million+ businesses using ChatGPT at work, with case‑studies of productivity gains across functions like support, marketing, engineering, and operations OpenAI.
A Nielsen Norman Group study found that professionals using tools like ChatGPT can complete tasks faster and often with higher quality, though oversight is required NNG.
Case studies from vendors like BotsCrew and others show corporate deployments where ChatGPT‑based bots handle internal FAQs, policy questions, and IT support, reducing ticket volume and response times BotsCrew case.

How effective is ChatGPT’s Company Knowledge for real‑world enterprises?

Where ChatGPT Business Shines

General reasoning & “Swiss‑army knife” use
ChatGPT is excellent at:
- Drafting and editing documents and emails
- Summarizing long content or meeting notes
- Brainstorming and planning
- Writing and explaining code
- Translating between languages and formats
These strengths apply even without deep enterprise search integration, which is why adoption is so broad across many industries OpenAI usage paper.
Fast time‑to‑value
Teams can start using ChatGPT Business with minimal setup: enable SSO, invite users, and optionally add company knowledge via uploads or connectors. This is dramatically faster than rolling out a full enterprise search platform.
Company Knowledge feature
Newer capabilities let admins ingest internal docs so ChatGPT can answer questions grounded in company‑specific content. Third‑party commentary describes this as turning ChatGPT into an “enterprise brain” when configured correctly UC Today.
Ecosystem & integrations
Because ChatGPT is widely used, there is a large ecosystem of plugins, connectors, and wrappers that let organizations embed it in Slack, internal portals, or workflows (e.g., Team‑GPT, QuestionBase, BusinessGPT) Team‑GPT BusinessGPT.

Is ChatGPT Business enough, or do you still need a dedicated enterprise search tool?

Limitations & Risks of ChatGPT Business for Knowledge Management

Hallucinations and answer reliability
- Academic and industry analyses show that LLMs like ChatGPT still hallucinate, including in enterprise contexts, even when grounded MIT DINT.
- HR and management guidance warns that ChatGPT answers must be reviewed, especially in HR, legal, or compliance domains SHRM.
- BBC‑referenced research cited by HR analyst Josh Bersin suggests a high share of AI answers can be erroneous without careful prompt design and verification Bersin commentary.
For internal Q&A, this means ChatGPT cannot be treated as an authoritative knowledge system without strong retrieval grounding, guardrails, and human review.
Security and data‑leak concerns
The enterprise product has strong contractual/privacy controls, but organizations continue to worry about:
- Shadow AI: Employees pasting sensitive data into personal ChatGPT accounts outside official governance Cyberhaven.
- Documented incidents like Samsung engineers accidentally leaking code and confidential data via ChatGPT CIO Dive.
- Multiple security vendors have published lists of ChatGPT security risks (prompt injection, data exfiltration, logging visibility gaps, etc.) and market products like DLP and proxy solutions to mitigate them CSA SentinelOne.
Even if ChatGPT Enterprise itself is well‑secured, the pattern is clear: governance and controls around usage matter as much as the core product.
Not a full knowledge management system
Experts in KM argue that LLMs like ChatGPT are tools on top of knowledge systems, not replacements:
- A detailed piece on KM strategy notes that ChatGPT and Claude “will not replace knowledge management systems” because they lack taxonomy, lifecycle, ownership, and governance layers that KM platforms provide ExecsInTheKnow.
Using ChatGPT as the only knowledge layer is risky; it works best when it points into a well‑managed repository (or a tool like Glean) rather than being that repository.
Integration depth vs. dedicated search platforms
Several enterprise search vendors explicitly market themselves as better than ChatGPT for finding internal documents, focusing on:
- Rich filters and metadata
- Access control and audit trails
- Content lifecycle and curation Thinkfree
This underscores the gap between chat‑centric LLMs and search‑centric enterprise platforms.

What are the concrete security risks of ChatGPT Enterprise and how do companies mitigate them?

Head‑to‑Head: Glean vs. ChatGPT Business

1. Use‑Case Fit

Glean fits best when:

Your main pain is “I can’t find things across our tools”, and you want a single, secure search box.
You need strict permission mirroring from SaaS tools and clear source‑of‑truth citations.
You want search + lightweight AI agents that summarize or draft from existing internal content.

ChatGPT Business fits best when:

You want a general AI assistant that helps with writing, analysis, coding, and brainstorming as much as Q&A.
You’re okay combining it with other systems for indexing, permissions, and content governance.
Your teams already rely heavily on ChatGPT in their day‑to‑day work and you want to formalize and secure that usage.

2. Knowledge Grounding & Hallucinations

Glean is built around retrieval first; it markets and documents RAG patterns specifically tailored for enterprise search and emphasizes contextual grounding Glean RAG.
ChatGPT Business now supports company knowledge, but by design it remains a generative model with known hallucination risks, even with retrieval in the loop MIT DINT.

If accuracy and provenance of answers about internal policies, contracts, or procedures are paramount, Glean (or another search‑first tool) is generally safer as the primary entry point, with ChatGPT used downstream for drafting.

3. Security & Compliance

Glean:

Offers enterprise security features (SSO, SCIM, granular permissions, logs) and has a public Bugcrowd program Bugcrowd.
At the same time, some competitors and security consultancies highlight risks of centralizing access to all enterprise knowledge (if identities or permissions are compromised) and position their security story as stronger Lucidworks DoControl.

ChatGPT Business/Enterprise:

Provides strong contractual controls on data use (no training on your business data, enterprise isolation claims) and is the focus of extensive security documentation and third‑party guidance OpenAI Business Varonis.
But real‑world incidents (like Samsung) and DLP vendors show that user behavior (copy‑pasting sensitive data) and shadow AI are ongoing risks CIO Dive Cyberhaven.

Overall, both require identity, access management, and DLP to be properly configured; Glean’s risk is mostly about the breadth of indexed data, ChatGPT’s risk is more about where and how people use it (official vs personal contexts).

4. Deployment & Change Management

Glean: requires integration work, admin configuration, and intentional rollout. Once live, it can become a central “company brain” search bar.
ChatGPT Business: quicker to start, but to be safe and effective for internal Q&A you still need:
- Clear policies (what can/can’t be pasted)
- A strategy for company knowledge scoping
- Possibly a complementary search index or KM system.

For organizations that want quick wins and already use ChatGPT heavily, starting with ChatGPT Business plus limited company knowledge is common. For those building a structured digital workplace strategy, Glean or similar is often layered underneath.

What does an architecture look like where Glean and ChatGPT are used together?

Practical Buying Guidance

When to Choose Primarily Glean

Choose Glean as your anchor platform if:

Your biggest pain is fragmented knowledge across tools.
You have serious compliance / confidentiality requirements and want permissions‑aware retrieval with clear citations.
You’re willing to invest in deployment and change management to make “search first” a core behavior.

In this setup, ChatGPT (Business or not) can still be used as a companion for generation on top of content retrieved by Glean.

When to Lean on ChatGPT Business First

Choose ChatGPT Business as your main investment if:

Your early focus is broad productivity (writing, coding, analysis) across teams, not just search.
You’re still maturing your knowledge management and don’t yet have a clean content architecture.
You can implement strong governance: SSO, domain‑restricted access, policies, and – ideally – some DLP.

You can then add Glean or another enterprise search platform later, once the need for structured knowledge retrieval becomes acute.

When Using Both Makes Sense

For many mid‑size and large organizations, the realistic answer is both:

Glean (or similar) as the search and context engine
ChatGPT Business as the reasoning and generation surface

This pattern is already visible in third‑party content that compares Glean vs ChatGPT Enterprise, often concluding that they are complementary rather than pure substitutes Credal.

Key Takeaways

Glean ≈ search‑first Work AI: best when your main goal is to unify and secure search across all your work tools with low hallucination and good governance.
ChatGPT Business ≈ assistant‑first AI platform: best when you need a versatile assistant for many tasks, and are ready to wrap it in policies and supporting systems for knowledge and security.
They overlap in internal Q&A, but differ in depth: Glean is deeper in retrieval and enterprise search; ChatGPT is deeper in general reasoning and content creation.

If you treat either as a turnkey replacement for knowledge management, you’re likely to be disappointed. They work best as parts of a broader knowledge and AI architecture that includes content strategy, permissions, and human oversight.

How do total costs and ongoing overhead compare between Glean and ChatGPT Business?