Three.js vs Spline: Which for Web 3D?

Three.js vs Spline is a common question once a team decides it wants 3D on a website. The two sit at different levels. three.js is a JavaScript library that developers write code against. Spline is a design tool where designers build and animate 3D scenes visually, then publish them to the web. So the useful question is who will build and maintain the scene, and how much control you need over it.

What each one is

three.js describes itself as an easy-to-use, lightweight, cross-browser, general-purpose 3D library. It is open source under the MIT license, and its current builds include WebGL and WebGPU renderers. You write JavaScript to set up a scene, load models, add lights, handle interaction and render. Almost anything is possible, and all of it is your job.

Spline is a browser-based 3D design tool. Its documentation covers objects, materials, lighting, cameras, particles and physics, an interaction system of states, events and actions, and AI features for generating and editing. When the scene is ready, you export it: as a public URL, as a Spline Viewer web component, or as code. Spline's docs say it draws on WebGPU by default and falls back to WebGL automatically on browsers without WebGPU support.

How each gets onto your site

Spline Viewer. Spline's Viewer export is a native HTML web component. You copy a snippet into your site and the scene loads from Spline. Options include showing or hiding the Spline logo, a hint image that prompts visitors to interact, a loading spinner, and lazy loading, which is on by default and loads the canvas content only when it is visible on screen.

Before you publish, check the Renderer option in Spline's Play Settings. Auto, which the docs call the safest choice for a public audience, renders on WebGPU where the browser supports it and falls back to WebGL everywhere else. The WebGPU-only option shows browsers without support a "requires WebGPU" notice instead of your scene, and the docs say new scenes default to WebGPU.

Spline code export. Spline can export a scene as Vanilla JS, React, Next.js, three.js or react-three-fiber code, and its docs say you can download the code exports and host them on your own server. One caveat from the docs: "Animations and events are only enabled when exporting to Vanilla js and React." If you export to three.js code to take the scene further, plan to rebuild the interactions yourself.

three.js. You build the scene in code, usually loading models made in Blender or similar as glTF, which the three.js documentation recommends. You host every file. Our guide to adding 3D models to a website covers that pipeline.

Three.js vs Spline side by side

Who builds it. Spline: a designer, with little or no code. three.js: a developer, ideally one with 3D experience.

Speed to a first result. Spline is much quicker for a hero object, an animated illustration or a small interactive scene. three.js takes longer to reach the same point.

Control. three.js gives full control over rendering, shaders, loading, performance, and how the scene ties into the rest of your site: scroll position, a product configurator, data from your CMS or an API. Spline gives you its interaction model plus a code API for talking to the scene.

Performance tuning. In three.js you control every byte. In Spline you work within its options. Its own optimization guide recommends keeping subdivision levels and the sides on parametric shapes low, deleting objects that can't be seen, using as few image textures as possible, working with fewer than three lights per scene, going easy on post-processing effects, and keeping to one or two embeds per page, with the Viewer preferred over an iframe.

Cost structure. three.js is free; the cost is developer time. Spline has a free plan and several paid ones. When we checked Spline's pricing page for this post, web exports on the free plan carried a watermark, code export and GLTF export were listed on Pro and above, and self-hosted export on Enterprise. Check the current page before you commit, because plan features change.

Lock-in. A three.js scene is your code. A Spline scene lives in Spline unless you export it, and Vanilla JS exports run on Spline's own runtime package, @splinetool/runtime.

Maintenance. Designers can edit a Spline scene and republish it without a developer. A three.js scene needs a developer for most changes.

Which to choose

Choose Spline when:

• The 3D is a hero visual, an animated illustration or a small interactive moment.
• Designers will keep iterating on it after launch.
• You need it soon, and the scene doesn't need data from your systems.

Choose three.js when:

• The 3D is the product: a configurator, a data visualization, a game-like experience.
• It must react closely to scroll, page changes or app state.
• Performance budgets are strict, such as a mobile-heavy audience or a page where Core Web Vitals matter.
• You want no dependency on a third-party design platform.

Two hypothetical briefs show the rule at work. A CPA firm wants a slowly turning glass object behind its homepage headline, and its designer will restyle it each tax season: that is Spline, embedded with the Viewer and a fallback image. A packaging printer wants customers to pick a box style, enter dimensions and see artwork wrapped onto the box before requesting a quote: that scene depends on product data and form state, so it is a three.js build.

A hybrid also works. Prototype in Spline to agree on the look and motion, then build the production version in three.js. Or export models from Spline as glTF and load them into a three.js scene, keeping design in one tool and the code in your own hands.

First, do you need 3D at all?

Ask what the 3D does for the visitor. If it explains a product, invites exploration or sets a brand apart, it can earn its weight. If it only decorates, a well-made 2D animation may do the same job for less. Our founder's personal site opens on a split-flap greeting board: one focused interaction that gives the whole site its character. Before choosing a 3D tool, ask whether a focused interaction like that would serve your visitors better. Our post on WebGL helps you judge when 3D is worth it.

A quick checklist

• Who will edit the scene after launch?
• What does the scene need to respond to: scroll, user input, product data?
• What is the performance budget on a mid-range phone?
• Is a Spline subscription acceptable as a long-term dependency?
• Is there a fallback image for slow devices and for visitors who prefer reduced motion?
• Who owns the source files if you change agencies?

How Pinn.Media builds web 3D

We use both and pick per project: Spline when a designer-owned scene is the right fit, three.js when the 3D needs to be part of the product. If you are weighing Three.js vs Spline for a site or a campaign, book a discovery call and show us what you have in mind.