
Invision
Axure
Balsamiq
Proto.io
Flinto
Moqups
Framer
Collaboration app for UI designers & frontend developers

Coassemble
Trainn.co
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.

Which is more popular?
Based on our record, Zeplin seems to be more popular. It has been mentioned 23 times since March 2021.
Website, pricing, platforms and company facts side by side.
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| Website | zeplin.io | underlayerhq.com |
| Pricing | ||
| Company | Startup from the United States | Startup from the United Arab Emirates · 1 - 9 employees · 2026 |
| Listed in |
In their own words, as submitted to SaaSHub.


No description of Zeplin 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...
What each product offers, as listed by its team.


Possible disadvantages
No features have been listed yet.
An editorial look at what each product does well and who it suits.


Overall verdict
Why this product is good
Recommended for
Zeplin is best suited for designers and developers working in teams where clear design specifications and organized collaboration are critical. It's particularly beneficial for teams using Figma, Sketch, or Adobe XD who want to ensure precise design implementation and reduce misunderstandings between design and development departments.
No analysis of Underlayer yet.
Walkthroughs and reviews on video.
Zeplin Basics: Design Systems
More videos
Underlayer demo
How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing Zeplin and Underlayer.
Underlayer's answer:
it's pre-launching
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.
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.
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.
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.
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.
Share your experience with using Zeplin and Underlayer. For example, how are they different and which one is better?
External articles and on-site reviews we used to compare the two products.


As aforementioned, Zeplin suffers some inherent drawbacks that may dent designers’ hopes for faster, easy, and reliable UI design. To avert such scenarios, you don’t have to get stuck with Zeplin as there are numerous...
Zeplin is super affordable. It offers 2 plans: Team, which costs $8.00 per user per month, and Establishment, which costs $16.00 monthly. Zeplin also provides a feature-limited Free Plan and Enterprise Plan.
Zeplin is a workspace collaboration tool to document what to build and how designs should behave in a central collaborative place for the entire dev team.
We have no reviews of Underlayer yet. Be the first one to post
Recommendations tracked on public social media and blogs since March 2021.


Tools like Zeplin's AI layer, Supernova, and the emerging generation of Figma plugins with AI backends do this today. The output is not a PDF full of screenshots. It is structured data: exact values, token references, and context — the... - Source: dev.to / 7 months ago
Zeplin.io AI-powered design-to-dev handoff. - Source: dev.to / over 1 year ago
Additionally, thank you to all our community launch partners across the frontend ecosystem for helping us bring Storybook 8 to the world! Thanks to Chromatic, Figma, ViteConf, Omlet, DivRiots, story.to.design, StackBlitz, UXpin, Nx, Mock... - Source: dev.to / over 2 years ago
Tracking Underlayer since Sep 2026.
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Balsamiq. Rapid, effective and fun wireframing software.
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Create fully-interactive high-fidelity prototypes in minutes that look and work exactly like your app should. Sign up for a free 15-day trial and get started.
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