Custom JavaScript vs HubL templates for knowledge base customization: maintainability and upgrade risks

CRM HubSpot
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1

We’re redesigning our knowledge base in hs-2022 and debating whether to use custom JavaScript for dynamic features or stick with HubL templates rendered server-side. Our team is split on the best approach.

The JavaScript camp argues for better interactivity and modern UX patterns - things like instant search filtering, dynamic content loading, and smooth animations. The HubL camp emphasizes maintainability and upgrade compatibility, since HubSpot’s template system gets official support and updates.

I’m curious what others have experienced. For those who’ve built complex knowledge base customizations, which approach has proven more sustainable long-term? Are there specific use cases where one clearly wins over the other? Would love to hear real-world experiences with both approaches.

2

For that level of complexity, HubL alone won’t cut it. But here’s the thing - you can use HubL to output data structures that JavaScript then manipulates. Render your articles with HubL including all the metadata and custom properties as data attributes. Then use JavaScript to build the advanced filtering on top of that. You get the best of both worlds - HubL handles the data layer and upgrade compatibility, JavaScript handles the interaction layer.

3

Having built multiple knowledge bases in hs-2022, I can share what actually works long-term across all three considerations.

Maintainability Reality: HubL wins decisively here. Every HubSpot platform update in the past two years has been backward compatible with HubL templates. JavaScript customizations break more frequently - not catastrophically, but enough to require developer attention. We track maintenance hours: HubL-based KBs average 4 hours per quarter for updates, JavaScript-heavy KBs average 18 hours. That’s a 4.5x difference in ongoing maintenance cost.

Upgrade Compatibility Deep Dive: The Design Manager in hs-2022 has excellent tooling for HubL template versioning and testing. When HubSpot releases updates, you can test template changes in staging before deploying. JavaScript customizations don’t have this safety net - you discover breakage in production. The hybrid approach Carlos mentioned is smart, but requires discipline: document which DOM elements your JavaScript depends on, and build defensively with feature detection and graceful degradation.

Customization Flexibility Trade-offs: For your specific requirements (multi-faceted search, dynamic reorganization, personalization), here’s the practical breakdown:

  • Multi-faceted search: Use HubL to render all article metadata into the page, then JavaScript for client-side filtering. HubSpot’s search API has rate limits that make pure-JS solutions problematic at scale.
  • Dynamic category reorganization: HubL with AJAX endpoints. Render initial structure server-side, fetch updates via lightweight API calls.
  • Personalized recommendations: This requires JavaScript for behavioral tracking, but use HubSpot’s native personalization tokens in HubL where possible.

The pattern that works: HubL as the foundation (60-70% of functionality), JavaScript for enhancement (30-40%). Specifically, use HubL for content structure, navigation, initial rendering, and SEO-critical elements. Use JavaScript for search filtering, interactive widgets, analytics tracking, and dynamic updates that don’t affect core functionality.

Real-world example: Our client portal KB uses HubL templates for all article pages and category listings. We added JavaScript for instant search (filters pre-rendered HubL content), reading progress indicators, and related article recommendations. When hs-2022 to hs-2023 migration happened, zero template changes needed. We only updated one JavaScript module that depended on a deprecated CSS class.

The key insight: Customization flexibility isn’t about choosing one technology - it’s about choosing the right layer for each feature. HubL gives you upgrade-proof structure, JavaScript gives you interaction richness. Use both deliberately rather than defaulting to one.

4

The hybrid approach makes sense. What about customization flexibility though? We want to do some advanced filtering that I’m not sure HubL can handle - like multi-faceted search across custom properties, dynamic category reorganization, and personalized content recommendations based on user behavior. Can HubL really support that level of complexity?

5

We went heavy on JavaScript for our KB and honestly, it’s been a mixed bag. The UX is fantastic - users love the instant search and dynamic filtering. But every HubSpot update makes me nervous. We’ve had to refactor twice when HubSpot changed their DOM structure. If you go the JS route, abstract your selectors and DOM manipulation into a separate layer so you can adapt to platform changes easily.