Software Alternatives & Startups

Blocks.js VS Underlayer

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

Blocks.js

Deprecated repository. Contribute to Tixit/blocks.js development by creating an account on GitHub.

Rating
0 reviews
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
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Which is more popular?

Javascript UI Libraries popularity
100% vs 0%
alternatives listed
38 vs 2

Base details

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

Blocks.js
Underlayer
Website github.com underlayerhq.com
Pricing —
Freemium $149 / Monthly Official pricing
Company — Startup from the United Arab Emirates · 1 - 9 employees · 2026
Listed in

About Blocks.js and Underlayer

In their own words, as submitted to SaaSHub.

Blocks.js
Underlayer

No description of Blocks.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.

Blocks.js 4 features
Underlayer 0 features
  • Modular Design
    Blocks.js allows for modular design construction with reusable and composable components, which enhances maintainability and scalability of projects.
  • Ease of Use
    The library is designed to be easy to use with a minimalistic approach, making it accessible for developers who want to build and manage DOM elements with less boilerplate.
  • Flexibility
    Blocks.js offers flexibility in building and managing UI components, enabling developers to create highly customized web interfaces without being restricted by typical framework constraints.
  • Efficient Component Updates
    It provides efficient ways to update the DOM, improving performance especially for applications that require frequent updates or changes to the UI.

Possible disadvantages

  • Limited Popularity and Community Support
    Blocks.js is not as widely used as other UI libraries or frameworks, which might limit community support and resources available for troubleshooting or learning.
  • Lack of Comprehensive Documentation
    The library might not have exhaustive documentation, which can be a barrier for new users trying to learn and implement it properly.
  • Features Compared to Established Frameworks
    Compared to established frameworks like React or Angular, Blocks.js may lack some advanced features or optimizations, which could be crucial for certain complex applications.
  • Potential Integration Challenges
    Integrating Blocks.js with other libraries or existing projects might present challenges, especially if those projects are built with frameworks that have differing paradigms.

No features have been listed yet.

Videos

Walkthroughs and reviews on video.

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

No Blocks.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
Blocks.js
Underlayer
100% 100%
0% 0%
0% 0%
100% 100%
100% 100%
0% 0%
0% 0%
100% 100%

Questions & Answers

As answered by people managing Blocks.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

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Alternatives to Blocks.js and Underlayer

When comparing Blocks.js and Underlayer, you can also consider the following products.