Huggingface Spaces

Hugging Face Spaces

Hugging Face Spaces host machine-learning applications. There are 1M+ today; each Space is a git repo. This skill covers creating, building, debugging, and maintaining them.

0. Getting ready

Before anything else:

1. Check the hf CLI is installed: which hf. If not, pip install -U huggingface_hub.
2. Check the user is logged in: hf auth whoami. If not, run hf auth login — it prints a URL and a one-time code; ask the user to open the URL and enter the code, then login completes automatically (OAuth, no token needed). Alternatively, pass a write-scoped token from https://huggingface.co/settings/tokens with --token.
3. Note whoami's canPay and isPro flags — they gate hardware choices below.

The hf-cli skill teaches an agent every hf command and is the recommended companion to this one. Install it with hf skills add hf-cli (add --claude --global to install for Claude Code as well, user-level).

1. What a Space is

A Space is a git repo with three possible SDKs:

• Gradio — most Spaces. Python, fast iteration, supports ZeroGPU.
• Docker — arbitrary container. Use when you need a non-Python stack or a pre-built template (Streamlit, Argilla, Shiny, etc. — full list at https://huggingface.co/docs/hub/spaces-sdks-docker). Does not support ZeroGPU.
• Static — plain HTML, or a React/Svelte/Vue project built at deploy time. Use for in-browser ML (transformers.js / WebGPU / WebAssembly / onnxruntime-web), project pages, interactive reports, or Spaces that orchestrate other Spaces. No hardware needed.

Hardware tiers

Free, no creator cost: cpu-basic and zero-a10g (ZeroGPU). Static Spaces are also free and don't need hardware.

cpu-basic — 2 vCPU / 16 GB. For data viz, API-proxy Spaces, small CPU-bound models.

ZeroGPU (zero-a10g) — dynamic, per-request GPU allocation on NVIDIA RTX PRO 6000 Blackwell (sm_120). Two sizes: large (half MIG, 48 GB, 1× quota) and xlarge (full, 96 GB, 2× quota). Free for the Space creator; Space visitors consume their own daily quota (~5 min free / 40 min Pro / 60 min Enterprise). Gradio-only, PyTorch-first. Requires the creator to be on a PRO / Team / Enterprise plan.

Dedicated GPU (T4, L4, A10G, L40S, A100, H200) — billed to the Space creator by the hour. List + pricing: hf spaces hardware. Only the creator can attach these, and only if canPay=True. Use when ZeroGPU genuinely doesn't fit — non-PyTorch main model with heavy init, very-large-model long-context inference, etc.

If a non-PRO user has a use case that wants ZeroGPU, you can still build it: create a cpu-basic Space, code the app for ZeroGPU, push, then request a community grant. See references/grants.md.

For the authoritative reference: https://huggingface.co/docs/hub/spaces-overview

2. Look for an existing demo first

Before deciding how to build anything, search for prior art:

hf spaces search "<model name or task>" --sdk gradio --limit 10

If someone has built a similar Space, read its app.py and requirements.txt — that gives you the working pattern. Saves a lot of blind iteration. Mention to the user what you found before committing to an approach.

3. Decide SDK and hardware

Follow the user's explicit request first. If they were vague:

• Default for a public ML demo: Gradio + ZeroGPU. Use this unless something below applies.
• The model's only inference path is non-PyTorch (ONNX / TF / JAX / vLLM as the MAIN model, with heavy init): dedicated GPU.
  • But: marginal non-torch tools (a small ONNX preprocessor, a TF utility) inside a torch-main pipeline are fine on ZeroGPU. The hijack only patches torch; init the non-torch lib inside @spaces.GPU and pay the short per-call init cost.
• Tiny / CPU-bound model, or API-proxy Space: cpu-basic (hardware-free isn't applicable to Gradio).
• Browser-side ML or project page: Static.
• Container with non-Python stack: Docker.

Sourcing the model

• GitHub repo — clone locally to read structure. If it already has a Gradio demo, the minimal viable path is to adapt it onto ZeroGPU (see references/zerogpu.md). Otherwise: read the README + inference code, prefer the PyTorch path, estimate VRAM (bf16 ≈ params_B × 2 GB; 48 GB fits ≤24B params at bf16, or much larger with quantization — see references/zerogpu.md for quantization on ZeroGPU).
• HF model repo — read its README, follow any linked GitHub.
• Paper / blog post — look for an official or unofficial implementation. Don't reimplement unless trivial or the user explicitly asks.
• Vague request — search Spaces first; surface results.

If the model genuinely won't fit, check Inference Providers as an alternative: see references/inference-providers.md. This avoids hosting the model at all.

4. Create the Space

hf repos create <namespace>/<name> --type space --space-sdk <gradio|docker|static> \
    [--flavor zero-a10g|cpu-basic|<paid-flavor>] \
    [--secrets KEY=val] [--env KEY=val] \
    --public|--private|--protected \
    --exist-ok

• --space-sdk is required.
• --flavor selects hardware. zero-a10g is the (legacy) identifier for ZeroGPU. Omit for cpu-basic. Run hf spaces hardware for the full paid list and pricing.
• Visibility: --public (anyone can view), --private (only you), --protected (app is reachable but git repo / Files tab is private).
• --secrets KEY=val becomes an environment variable inside the Space and is not visible to visitors. Use for API keys, gated-repo tokens (HF_TOKEN=hf_…), etc. Can also be set later via hf spaces secrets set <id> KEY=val.
• --env KEY=val is visible to visitors — use only for non-sensitive config (GRADIO_SSR_MODE=false, PYTORCH_CUDA_ALLOC_CONF=expandable_segments:True, etc.).

Note: hardware: in the README YAML is silently ignored — hardware is only set via --flavor at creation, or later via hf spaces settings <id> --hardware <name>.

5. Build the app

The Space now exists at https://huggingface.co/spaces/<namespace>/<name> but is empty.

README.md frontmatter

Always required:

---
title: ...
emoji: 🚀                # pick something representative
colorFrom: blue          # red|yellow|green|blue|indigo|purple|pink|gray (only these)
colorTo: indigo
sdk: gradio              # gradio | docker | static
sdk_version: 6.15.1      # latest stable unless you have a reason*
app_file: app.py         # gradio only (docker / static use Dockerfile / index.html)
short_description: ...   # ≤ 60 chars (server rejects longer)
python_version: "3.12"   # ZeroGPU officially supports 3.10.13 and 3.12.12
startup_duration_timeout: 30m   # default; bump to 1h for big LLMs / heavy downloads
---

* Default to the current latest stable, and look up what that is (pip index versions gradio, or the version a freshly-created Space defaults to) — the number above is a placeholder that goes stale, don't reuse it. Only pin older when the latest genuinely doesn't work for this Space: a custom component pins it, or you're adapting an existing demo and don't want to rewrite for 5.x→6.x breaking changes. If you need a 5.x, pick 5.50.0 (latest of the series; still supports custom components).

All frontmatter options: https://huggingface.co/docs/hub/spaces-config-reference

Minimal ZeroGPU Gradio app

import spaces           # MUST come before torch / diffusers / transformers
import torch
import gradio as gr
from diffusers import DiffusionPipeline

pipe = DiffusionPipeline.from_pretrained("<repo>", torch_dtype=torch.bfloat16).to("cuda")

@spaces.GPU(duration=60)
def generate(prompt: str):
    """Generate an image from a text prompt."""   # docstring → API / MCP tool description
    return pipe(prompt).images[0]

gr.Interface(fn=generate, inputs=gr.Text(), outputs=gr.Image()).launch(mcp_server=True)

Three rules — full treatment in references/zerogpu.md:

1. import spaces before torch / any CUDA-touching import. It monkey-patches torch.cuda.*; once CUDA is initialized in the main process, it's too late.
2. Load the model at module scope, .to("cuda") eagerly. ZeroGPU intercepts the call, packs weights to disk, and streams them into VRAM on the first @spaces.GPU entry. Lazy loading inside the decorator costs every user.
3. Decorate the function Gradio binds. Estimate duration to the realistic worst case (smaller = higher queue priority and tighter quota check). For input-dependent runtime, pass a callable.

Examples, docstrings, and MCP

• Add gr.Examples whenever it makes sense (the app takes input and representative inputs exist) — prefer the model/repo's own official examples. Keep example rows to the few inputs a user actually varies (prompt, image) and give the handler defaults for the rest (steps, seed, guidance) so a row is ["a prompt"], not a wall of knobs. Use cache_examples=True, cache_mode="lazy". See references/gradio.md.
• Give every API-triggered function a docstring and type hints. Each Gradio event handler is exposed over the API; the docstring + signature are what a caller — and the MCP tool schema — sees.
• Launch with demo.launch(mcp_server=True) (Gradio 5+) so the Space doubles as an MCP server: each API function becomes an MCP tool described by its docstring and hints.