Build with frontier AI models
Browse frontier models for coding, frontend design, 3D builds, research, content, slides, spreadsheets, automation, and long-running browser agents on Happycapy. Compare strengths, pick a model, describe what you want, and it builds in your browser. No API keys, no setup.
Agent modelAnthropic/Opus 5
Anthropic's newest Opus-tier flagship: near-frontier intelligence for complex agentic coding and enterprise work, with a 1M-token context and a cost/capability toggle.
Index scores (0–100) per Artificial Analysis, via OpenRouter (Aug 2026)
Try it nowxAI/Grok 4.6
xAI/Grok 4.6A 500K-token context, stronger long-running agents, and top-tier coding, built for ambitious interactive and visual builds.
Index scores (0–100) per Artificial Analysis, via OpenRouter (Aug 2026)
Try it nowZ.ai/GLM 5.3 Flash
One-shot websites, browser games, and Three.js 3D scenes from a single prompt, at flash speed and near-zero cost. A sparse MoE that fires only about 18B of its roughly 320B parameters per token keeps long agent runs cheap, and it holds near-Opus scores on agentic coding while excelling at playable games, WebGL and 3D, and audio visualizers.
Moonshot AI/Kimi K3
Moonshot AI/Kimi K3A natively multimodal 2.8T-parameter model with a 1M-token context, top-ranked for front-end web development and built for long-horizon coding, knowledge work, and deep reasoning.
Index scores (0–100) per Artificial Analysis, via OpenRouter (Aug 2026)
Try it nowAlibaba/Qwen 3.8 Max
Alibaba/Qwen 3.8 MaxAlibaba’s flagship Qwen model, a standout at one-shot 3D worlds, WebGL/Three.js games, shaders, and front-end builds, with long-horizon agentic coding at a fraction of the token cost.
Index scores (0–100) per Artificial Analysis, via OpenRouter (Aug 2026)
Try it now
Video modelByteDance/Seedance 2.5
ByteDance’s latest video model, generate a full, continuous 30-second scene from a single prompt, with precise reference control, native synchronized audio, and powerful editing.
Best AI model by task
Route the work to the model that naturally fits it.
Start with the outcome you want, then choose the model profile that fits the work. Happycapy brings coding, research, creative, and automation models into one browser workspace so agents can move from prompt to finished deliverable.
Coding and frontend
Use models with strong code generation, design sense, long-context awareness, and reliable tool use for polished interfaces and multi-file projects.
Research and documents
Pick long-context, reasoning-heavy models for synthesis across PDFs, documents, datasets, meeting notes, and web research.
3D, games and visuals
Use models with strong spatial reasoning and tool use for browser 3D, simulations, generated assets, videos, and game prototypes.
Automations and agents
Choose fast, tool-using models for recurring tasks that browse, run code, update files, create deliverables, and keep working 24/7.
Generate use cases
Turn any model choice into a finished workflow.
After you choose a model profile, ask Happycapy to generate a website, content system, research dashboard, dataset, deck, video, or automation. These examples mirror the kind of work shown in the Happycapy use case gallery.
Comparison layer
A compact table for humans and crawlers.
One row per model: what each is best for, why you’d pick it, and how it works inside Happycapy.
| Model | Best for | Why choose it | Happycapy workflow |
|---|---|---|---|
| Opus 5 | Agentic coding, enterprise work, long-running agents | Opus-tier intelligence tuned for agentic work, with a 1M-token context and effort levels, at near-Fable-5 quality for about half the price. | Draft specs, edit across files, run and review code, and orchestrate long multi-step agents in a secure sandbox. |
| Grok 4.6 | Long-running agents, ambitious interactive builds, coding | Frontier reasoning at speed, with a 500K-token context, top-tier coding scores, and strong first-pass app structure. | Turn one prompt into an interactive app, plan and run multi-step build loops, and iterate to a finished result. |
| GLM 5.3 Flash | One-shot games and browser 3D, coding, rapid prototyping | A sparse MoE that fires about 18B of roughly 320B parameters per token, so long agent runs stay cheap, with near-Opus agentic-coding scores. | Turn one prompt into a website, browser game, or Three.js scene, then iterate fast at near-zero cost. |
| Kimi K3 | Front-end web dev, long-horizon coding, multimodal work | Top-ranked front-end generation, natively multimodal, with a 1M-token context and an openly released frontier model. | Build responsive multi-page sites, generate slides and spreadsheets, and analyze documents in a secure sandbox. |
| Qwen 3.8 Max | One-shot 3D and WebGL, games and shaders, front-end | Standout one-shot Three.js/WebGL, shaders, and games with strong design taste, at competitive token cost. | Generate playable 3D worlds and games, build polished landing pages, and run long agentic build loops. |
| Seedance 2.5 | Video generation, product content, short-form social | Full continuous 30-second scenes from one prompt, with native synchronized audio and precise reference control and editing. | Generate text or image to video, refine with region and timestamp edits, and produce on-brand marketing clips. |
Pick any model above and put it to work in your browser.
Try a model freeFrequently asked
What is Happycapy?
Happycapy is an agent-native computer in your browser: pick a frontier AI model, describe what you want, and an agent plans, writes and runs code, and returns a finished website, dashboard, deck, dataset, or video. Nothing to install.
Which AI models can I use on Happycapy?
Happycapy runs frontier models including Claude Opus 5, Grok 4.6, GLM 5.3 Flash, Kimi K3, and Qwen 3.8 Max for coding and agentic work, plus Seedance 2.5 for video generation. Each has a dedicated page with benchmarks and examples.
How do I choose the right model?
Pick by the job: Opus 5 for complex agentic coding and enterprise work, Grok 4.6 for fast interactive and visual builds, GLM 5.3 Flash for one-shot games and browser 3D at low cost, Kimi K3 and Qwen 3.8 Max for front-end, 3D, and games, and Seedance 2.5 to generate video. You can switch models anytime inside a project.
Do I need API keys or any setup?
No. Every model runs on Happycapy’s agent-native computer in your browser, with no API keys, installs, or configuration. Sign up, pick a model, and describe what you want to build.
Where can I see real examples?
Browse the use case gallery for finished, remixable builds: websites, content systems, research dashboards, datasets, decks, and videos made with these models. Open any example to see the result, then remix it into your own project in one click.
Is it free to try?
Yes. You can start building for free and upgrade for more usage. See the pricing page for current plans and included credits.
Pick a model and start building
Every model runs on the same agent-native computer, so you can switch anytime. Start free, no setup required.
Get started free