Should I build internal search on Elastic or use something like Glean?

It depends on what kind of “internal search” you’re building.

Short answer

• Use Elastic if you want to build and own the search experience, have custom data models, and need tight control over ranking, access control, and cost at scale.
• Use Glean if you want a fast-to-deploy employee search/productivity layer that connects to lots of SaaS tools and you’d rather buy than build.

How to choose

Pick Elastic if:

• Search is a core product capability or important differentiator
• You need deep customization of relevance, filters, facets, or workflows
• You have nonstandard data sources or complex documents
• You need full control over indexing, permissions, and query logic
• Your team can support ongoing search engineering and ops
• You care about avoiding per-seat SaaS costs as usage grows

Pick Glean if:

• You want employee search across Google Drive, Slack, Confluence, Jira, etc.
• You need value quickly without building ingestion, permissions, ranking, and UX from scratch
• Your search needs are mostly knowledge discovery, not a bespoke application
• You’re okay with a SaaS product opinionated about UX and ranking
• You want built-in integrations and admin-friendly setup

The real tradeoff

Elastic

Pros:

• Maximum flexibility
• Lower vendor lock-in
• Can be cheaper at scale if well-operated
• Good for app search and custom retrieval use cases

Cons:

• You own ingestion, relevance, permissions, analytics, and tuning
• Significant engineering effort
• Search quality can be hard to get right
• Ongoing operational overhead

Glean

Pros:

• Fast time to value
• Strong out-of-the-box connectors
• Better “employee search” experience out of the box
• Less engineering burden

Cons:

• Less control over the search stack
• Can be expensive, especially at larger headcount
• May not fit custom apps or specialized ranking needs
• Vendor dependency

A simple decision rule

Ask:

1. Is this an internal employee search tool or a product feature?

   • Employee knowledge search → lean Glean
   • Product/search feature in your app → lean Elastic

2. Do you need to customize ranking and retrieval heavily?

   • Yes → Elastic
   • No → Glean

3. Do you want to spend engineering time on search infrastructure?

   • Yes → Elastic
   • No → Glean

4. Are your sources mostly SaaS tools already supported by Glean?

   • Yes → Glean
   • No → Elastic or custom build

Practical recommendation

• If you’re a company building internal employee search for common tools: start with Glean.
• If you’re building search into a product, or have special data/permission logic: build on Elastic.
• If you’re unsure, prototype both:
  • Try Glean for an admin/user pilot
  • Prototype Elastic on one high-value source and measure relevance/work effort

One more consideration: security and permissions

This is often the hidden deciding factor.

• If permissions are straightforward and mapped from SaaS connectors, Glean handles a lot for you.
• If permissions are complex, dynamic, or app-specific, Elastic gives you more control—but you must implement it carefully.

If you want, I can help you decide based on your exact use case with a quick checklist:

• internal employee search vs product search
• data sources
• user count
• permission complexity
• engineering capacity
• budget constraints