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highlight.js VS Underlayer

Compare highlight.js VS Underlayer and see what are their differences

highlight.js

Highlight.js is a syntax highlighter written in JavaScript. It works in the browser as well as on the server.

Rating
0 reviews
Pricing
Open source
Alternatives Is it good?
Underlayer

Build courses by API, drop them into your product with one iframe, and get told who finished. No portal, no learner accounts, priced per course view.

Rating
0 reviews
Pricing
Freemium $149 / Monthly
Alternatives Is it good?
Calcumber
Calculate in a notebook and share — from everyday math to engineering. sponsored
Note: These products don't have any matching categories. If you think this is a mistake, please edit the details of one of the products and suggest appropriate categories.

Which is more popular?

Based on our record, highlight.js seems to be more popular. It has been mentioned 57 times since March 2021.

social mentions
57 vs 0
App Reviews popularity
100% vs 0%
alternatives listed
53 vs 2

Base details

Website, pricing, platforms and company facts side by side.

highlight.js
Underlayer
Website highlightjs.org underlayerhq.com
Pricing
Open source
Freemium $149 / Monthly Official pricing
Company — Startup from the United Arab Emirates · 1 - 9 employees · 2026
Listed in
Customer Feedback App Reviews Marketing Tools Documentation +1
Education E-learning Education / E-Learning

About highlight.js and Underlayer

In their own words, as submitted to SaaSHub.

highlight.js
Underlayer

No description of highlight.js yet.

Underlayer is headless, API-first training for SaaS products. Instead of sending your users to a separate LMS portal, you generate a course, embed it where they already work, and get every completion sent back to your own systems. How it works Create a course. Generate one from a doc or a prompt...

Read more about Underlayer

Features and specs

What each product offers, as listed by its team.

highlight.js 5 features
Underlayer 0 features
  • Wide Language Support
    Highlight.js supports a comprehensive range of programming languages out of the box, making it versatile for various projects.
  • Automatic Language Detection
    It can automatically detect the programming language of a code block, reducing the setup time and effort for developers.
  • Customization
    Highlight.js offers numerous themes and customization options, allowing developers to easily tailor the syntax highlighting to match their application's aesthetic.
  • Lightweight and Fast
    The library is lightweight and performs efficiently, ensuring quick load times and a seamless user experience.
  • Open Source
    As an open-source project, Highlight.js benefits from community contributions and is free to use, modify, and distribute.

Possible disadvantages

  • Limited Dynamic Features
    Highlight.js is primarily used for static code block highlighting and lacks advanced features like real-time editing or complex code analysis.
  • Manual Updates
    New languages or updates may not be immediately available, requiring users to manually update the library or find alternatives for less common languages.
  • Performance Degradation on Large Files
    Highlight.js may experience performance issues when rendering very large code files, potentially slowing down page load times.
  • Dependency Management
    As with many JavaScript libraries, managing dependencies and ensuring compatibility with other libraries or frameworks can be challenging.

No features have been listed yet.

Videos

Walkthroughs and reviews on video.

highlight.js 0 videos + Add
Underlayer 1 video + Add

No highlight.js videos yet. You could help us improve this page by suggesting one.

Underlayer demo

Category popularity

How often each product is chosen within a category, 0–100% relative to the other.

Score bands 0–20 21–40 41–50 51–60 61–100
highlight.js
Underlayer
100% 100%
App Reviews
0% 0%
0% 0%
Education
100% 100%
100% 100%
Customer Feedback
0% 0%
0% 0%
E-learning
100% 100%

Questions & Answers

As answered by people managing highlight.js and Underlayer.

Who are some of the biggest customers of your product?

Underlayer's answer:

it's pre-launching

What makes your product unique?

Underlayer's answer:

Underlayer is training with no portal. You build a course by API, by MCP, or in the visual builder, and add it to your product with one iframe. Then signed webhooks tell your systems who finished. Learners never create an account or leave your app, and the player uses your theme, so it looks like part of your product. We charge per course view, not per seat, and every price and overage rate is published.

Why should a person choose your product over its competitors?

Underlayer's answer:

Most course tools, like Coassemble, Trainn and LearningStudioAI, assume training happens on their own site: learners sign up, log in and get enrolled, and you pay per seat. Underlayer takes the opposite approach:

No learner accounts. You pass in your own user IDs and we track progress against them. Built for developers. A full REST API covers every resource, and an MCP server lets AI agents create and edit courses. Results in your own tools. Signed webhooks send completions to your CRM, your product or your data warehouse. SCORM 1.2 and 2004 export for customers who still need to load courses into an LMS. Public pricing. Plans start at $149/month for 25,000 course views, with unlimited learners and no sales call required.

How would you describe the primary audience of your product?

Underlayer's answer:

SaaS product, customer success and engineering teams who want onboarding, product education or compliance training inside their own app. It also suits platforms that train other people's users, like partner networks, marketplaces and field-ops tools, where a separate LMS login gets in the way.

What's the story behind your product?

Underlayer's answer:

Every company putting training in front of its users hit the same wall: the LMS wanted to own the learner. That meant a separate portal, a second login and a per-seat bill for people who never opened a course. We built Underlayer as the layer underneath instead. You keep the product and the user relationship. We handle building the course, playing it and tracking progress, and we stay out of the way.

Which are the primary technologies used for building your product?

Underlayer's answer:

Next.js 16 (App Router) with React 19 and TypeScript, Tailwind CSS v4, and Supabase (Postgres with row-level security, Auth and Storage). Claude from Anthropic generates courses with AI. Stripe handles billing and Resend sends email. There is also a remote MCP server with OAuth 2.1 for AI-agent access.

User comments

Share your experience with using highlight.js and Underlayer. For example, how are they different and which one is better?

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Social recommendations and mentions

Recommendations tracked on public social media and blogs since March 2021.

highlight.js 57 mentions
Underlayer 0 mentions
  • Angular’s New injectAsync() API Explained
    In our demo application, we're using highlight.js and Marked for markdown processing and syntax highlighting. - Source: dev.to / 5 months ago
  • Open-Source N8N Alternative for Workflow Building (GUI and Docker Included)
    In your website you could use https://highlightjs.org/ to syntax highlight the blocks of code. - Source: Hacker News / 11 months ago
  • A better pkg.go.dev
    Every time a request come in, we forward it to the pkg.go.dev server, then append the highlight.js script to the response before sending it back to the client. - Source: dev.to / over 1 year ago

View more

Tracking Underlayer since Sep 2026.

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