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Three.js vs Unity WebGL — Web 3D vs Game Engine

Three.js for typical 3D websites; Unity WebGL for porting game projects to browser.

Three.js: web-first 3D library, small bundle, perfect for marketing sites and creative web. Unity WebGL: full game engine ported to browser, large bundle (50-200MB typical), suited for 3D web games. For typical 3D websites, Three.js wins decisively on bundle size, SEO compatibility, and integration with web tooling. Unity WebGL is the right choice when porting an existing Unity game to the web — but a brand-new website in Unity WebGL is overkill.

Migration cost

Going from the second to the first option later (after the project is live) is non-trivial — usually 30-50% of the original build cost in engineering time. The opposite direction (first to second) is rarely needed. So the choice at kickoff is the more important call. I help clients think through this in a 30-min call before any contract.

Quick summary

The short version: Three.js vs Unity WebGL — Web 3D vs Game Engine is a comparison between two real choices working developers actually face on production projects. Both options have valid use cases and neither dominates the other. The right pick depends on team skills, target browser support, and the specific 3D features your project needs.

When option A wins

Pick the first option when the team prefers a stable mature ecosystem with a large community, when the project will run on production for 5+ years (long-term maintainability), and when the design constraints are well-understood before kickoff. The first option also wins for projects with a meaningful budget that can afford engineering depth.

When option B wins

Pick the second option when speed-to-prototype matters more than long-term maintenance, when the team includes a generalist rather than a 3D specialist, and when the visual ambition fits within the framework's built-in capabilities. The second option ships fast and rarely fights the tooling, which matters for marketing-driven launches.

Frequently asked questions

Can I switch options later?

In one direction yes, in the other expensive. Going from a heavier tool to a lighter one is normal. Migrating from a lighter tool to a heavier one means rewriting most of the 3D layer, which is 30-50% of original build cost.

Which tool do you personally use?

I use both, depending on the project. For long-term maintenance projects with rich features, I default to the more mature option. For fast prototypes and marketing campaigns, I default to the faster-to-ship option. Tool-fit beats tool-loyalty.

How long does this take?

Standard scope: 4-6 weeks from contract signature to live site. Larger scope (configurator, multi-scene scrollytelling) takes 8-12 weeks. Rush projects (2-3 weeks) are accepted with a 30-40% rush surcharge.

What does it cost?

Hero-section 3D upgrade: \$1,500-\$2,500. Full multi-scene 3D site: \$3,500-\$8,000. Configurator with custom shaders: \$5,000-\$12,000. All fixed-price, source code included. EUR equivalents on request.

What if my visitors are on weak phones?

The site detects device tier before the first scene loads and serves a lighter version on weak hardware (fewer particles, simpler shaders). Devices without WebGL get a static fallback that preserves the visual language and conversion path.

Ready to ship a 3D experience?

Tell me what you need — fixed price, fixed deadline, no surprises.

Get a quote +381 61 224 8989