itch.io Publish (butler)

Get a build onto an itch.io page and keep it updated. The page is created in the browser; all uploads go through butler, itch.io's command-line tool, with one command you'll use forever: butler push. butler diffs against the previous build and uploads only what changed. Deep CI/CD and flag detail lives in references/butler-ci.md.

When to use

• Use when creating/updating an itch.io project page, installing or logging in to butler, uploading a build with butler push, choosing channel names, versioning uploads, or shipping a jam/demo/release build to itch.io.
• Triggers: butler push, butler login, channels, .itch.toml, "publish on itch", "upload to itch".

When not to use: publishing on Steam (use steam-publish); jam scope/planning (use game-jam — this skill is only the upload mechanics); building the game itself (engine skills).

Core workflow

1. Create the project page at itch.io/game/new — butler pushes only to a page that already exists. Set the Kind of project: keep Downloadable for native builds, or choose HTML for a browser-playable game (this is required for web builds — see Pitfalls). Set pricing and keep visibility at Draft (or Restricted for testers) until the page is finished: the first public publish puts it on Most Recent once, and it cannot go back to the top later.
2. Install butler and log in. Download from itchio.itch.io/butler, add it to PATH, then butler login (opens a browser to authorize). Verify with butler version. For CI, use BUTLER_API_KEY instead — see the reference. (The itch desktop app also has a graphical push screen that uses its own bundled butler, if the user prefers no CLI.)
3. Prepare a portable build folder — the exact files a player runs, nothing extra. Push a folder (or a single .zip of that folder), not an installer and not a pre-compressed archive of archives (hurts patching; see Pitfalls).
4. Push to a channel: butler push <dir> <user>/<game>:<channel>. <user>/<game> is the lowercase page address (finji.itch.io/overland → finji/overland). The channel name determines the platform tag (see Patterns). The first push uploads everything; later pushes to the same channel upload only the diff.
5. Fill in the Edit game page, then Save. Fix platform tags if a channel wasn't auto-tagged correctly — tick only platforms you have actually run the build on. For browser games also flip the page to HTML and tag the channel playable in browser. Answer the AI generation disclosure section if any shipped content was made with generative AI (mandatory for asset pages, which are delisted without it), and mark adult content under Metadata → Classification.
6. Version your builds (optional but recommended): --userversion 1.2.0 or --userversion-file build.txt so you control the version string players and the update API see.
7. Update later by pushing to the same channel again. Use butler status <user>/<game> to see channels/builds and butler push-preview to see what a push would change before sending it.

Patterns

1. The one command you need — butler push

# butler push <directory-or-zip> <user>/<game>:<channel>
butler push ./build/windows leafy/my-game:windows
butler push ./build/mac     leafy/my-game:osx
butler push ./build/linux   leafy/my-game:linux
butler push ./web           leafy/my-game:html   # browser build (also set page Kind = HTML)

2. Channel naming controls the platform tag (kebab-case, lowercase)

Substring in channel name -> auto-applied tag:
  win / windows  -> Windows        linux -> Linux
  mac / osx      -> macOS          android -> Android
Multiple platforms in one channel are allowed: e.g. a Java jar:
  butler push ./jar leafy/my-game:win-linux-mac
Convention: lowercase words separated by dashes (windows-beta, osx-demo, soundtrack).
Tags are only the INITIAL guess — fix them anytime on the Edit game page (then Save).
There is no tag for CPU architecture: name the channel (windows-arm64) if you ship several.

3. Version, verify, and preview

butler version                              # print version; confirms install + PATH
butler login                                # authorize this machine (opens browser)

# Set an explicit version string instead of itch's auto-incrementing integer:
butler push ./build leafy/my-game:windows --userversion 1.2.0
butler push ./build leafy/my-game:windows --userversion-file build_number.txt

butler status leafy/my-game                 # list channels + latest builds/versions
butler push-preview ./build leafy/my-game:windows   # NEW/MODIFIED/DELETED/SAME, uploads nothing

4. First-time, hidden, and filtered pushes

# Hide a brand-new channel from the page until you're ready (NEW channels only):
butler push ./build leafy/my-game:windows-beta --hidden

# Exclude files from the upload without copying the folder (--ignore is repeatable):
butler push ./build leafy/my-game:windows --ignore '*.pdb' --ignore '*.dSYM'

# Preview exactly what would be sent, without sending it:
butler push ./build leafy/my-game:windows --dry-run

Pitfalls

• Pushing an installer. itch.io patches portable builds; an installer (.exe/.msi) defeats patching and the itch app's auto-update, and may need admin rights players don't have. Push the extracted, runnable folder instead.
• Pre-compressed builds. Pushing a heavily compressed archive (or an archive of archives) makes patches huge — a tiny change rewrites the whole compressed blob. Push uncompressed files; itch.io compresses on its side.
• A folder containing only one .zip. butler auto-unzips it and pushes the contents (to avoid a "zip in a zip"). Pass --no-auto-unzip only if you truly want the zip uploaded as one opaque file.
• HTML5 game shows as a download. Two switches are required: set the page Kind to HTML and tag the channel playable in browser on the Edit game page after the first push — neither happens automatically from the channel name.
• HTML5 build loads a blank page or 403s. The upload needs index.html at its root and must stay within itch.io's limits: at most 1,000 files, 500 MB extracted, 200 MB per file, 240 characters per path. The CDN is case-sensitive, serves the game from a subfolder (so paths starting with / break — use relative paths), returns 403 for folder URLs, and only allows HTTPS requests to other domains. HTML5 pages take payment only as donations; sell a web game by making the page Downloadable.
• invalid target (bad user) / (bad game). The target must match the page address exactly — subdomain for the user, URL slug for the game, all lowercase — and the page must exist already.
• macOS .app loses its structure. Push the .app folder itself (or the folder that contains it); butler keeps the bundle as the top-level directory and marks Mac/Linux executables as executable by default.
• --hidden on an existing channel errors. It only applies when the push creates a new channel. Unhide later from Edit game.
• Channel typos make duplicate slots. windows and win-final are different channels and create separate downloads. Decide your channel names up front and reuse them.
• 30 GB cap. itch.io rejects builds whose total uncompressed size exceeds 30 GB.
• Paid page delisted or payouts frozen. Selling requires following the payment processors' rules (itch.io's creator FAQ lists themes card networks will not process), and adult content must be classified as such. Check before setting a price.
• Secrets in CI logs. A BUTLER_API_KEY printed in a public log is compromised — revoke it immediately on the API keys page. See the reference for safe CI usage.

References

• For CI/CD (GitHub Actions/GitLab) with BUTLER_API_KEY, automated install via broth, the full flag list, and the update-check API, read references/butler-ci.md.
• Primary docs: the butler manual — itch.io/docs/butler (installing, login, pushing); itch.io creator docs — itch.io/docs/creators/html5 (web build limits) and itch.io/docs/creators/quality-guidelines (tagging, AI disclosure, delisting rules).

Related skills

• steam-publish — the same game on Steam via SteamPipe (often shipped alongside itch.io).
• game-jam — most jams are hosted on itch.io; this skill handles the upload step.
• prototype-fast — share an early prototype on a Draft/restricted itch page for playtesting.