pastehtml.dev

Share HTML pages in seconds. Drop an HTML file, get a private link your friends can open, preview, and view the source of. Anonymous publishing still works, and accounts add folders, custom subdomains, view counts, browser-based re-upload updates, and account API keys for agent publishing into folders.

How it works

• Drag and drop (or browse for) an .html/.htm file up to 2 MB.
• The document is published at https://<token>.pastehtml.dev/ — or at a claimed custom subdomain like https://launch-plan.pastehtml.dev/ — with an inspector page (copy link, preview, highlighted source) at /p/<token>. Tokens are random 32-character lowercase-alphanumeric IDs (~165 bits of entropy — lowercase because they double as subdomains, and browsers lowercase hostnames), so random links are private unless shared.
• Pastes can be password-protected. Locked pastes require the password before the inspector page, raw bytes, rendered preview, or live subdomain are served.
• Signed-in users can save pastes into folders, see view counts, and re-upload a replacement .html/.htm file without changing the share link. Pastes can never be deleted. API-created update tokens still work for token-based automated updates.
• The share page offers a live preview (with an in-site fullscreen mode) and a Rouge-highlighted source view.
• Every paste is served as a real page from its own origin — https://<token>.pastehtml.dev/ — so scripts and localStorage work (review-progress checklists persist) while staying fully isolated from other pastes and from the app itself. The path-based /p/<token>/raw endpoint returns the paste's exact bytes as text/plain — a byte-exact copy for programmatic clients, immune to any CDN HTML rewriting in transit — while /p/<token>/render serves the same bytes as text/html inside a CSP sandbox.

Agent API

Publish without a browser — ideal for AI agents that produce design documents or implementation plans and want to hand back a share link. Anonymous publishing still works with no credentials; signed-in users can also create account API keys at /api_keys so an agent can publish into their account and target folders.

# Multipart upload
curl -F "file=@plan.html" https://pastehtml.dev/api/pastes

# Or stream the HTML straight from a pipe
curl --data-binary @plan.html -H "Content-Type: text/html" \
  "https://pastehtml.dev/api/pastes?filename=plan.html"

Anonymous creation returns 201 with { token, title, custom_subdomain, folder, owner, account_paste, password_protected, views_count, live_url, url, raw_url, render_url, markdown_url, update_token } (or 422 with { errors }). Account-key creation returns the same paste fields but omits update_token; update account-owned pastes with the account key so revoking the key stops that agent's future access. Add password=<secret> (or custom_subdomain=<name>, which requires an account key) to creation/update requests; send clear_password=1 on updates to remove a paste password. Fetch raw_url to read a paste's exact bytes back (text/plain, never rewritten in transit).

Account API keys for agents

A signed-in user can open API keys from the dashboard, create a key, and give that secret to an agent. Use it as either Authorization: Bearer pht_... or X-PasteHTML-API-Key: pht_.... When a valid account key is present on POST /api/pastes, the paste is owned by that user and appears in their dashboard. Folder targeting is account-only:

curl -H "Authorization: Bearer $PASTEHTML_API_KEY" \
  --data-binary @plan.html -H "Content-Type: text/html" \
  "https://pastehtml.dev/api/pastes?filename=plan.html&folder_name=Roadmap"

Use folder_name=<name> to find or create a folder under that account, folder_id=<id> to target an existing folder, and clear_folder=1 on updates to move a paste back to All pastes. Keys can also be scoped to a default folder when created; scoped keys always publish there, can update only pastes already in that folder, reject folder overrides, only list that folder through the folder API, and cannot create unrelated folders. Scoped keys are revoked automatically if the folder is deleted. Unscoped agents can discover existing folder IDs with:

curl -H "Authorization: Bearer $PASTEHTML_API_KEY" \
  https://pastehtml.dev/api/folders

Unscoped keys can create folders with either nested form params (folder[name]=Roadmap) or a simple top-level name=Roadmap, whichever is easier for the client. Folder-scoped keys receive 403 on folder creation.

An account key can update pastes owned by that account, while the per-paste update_token flow keeps working as long as the paste stays anonymous. If an agent needs to claim an anonymous paste into an account, send the account key in Authorization: Bearer ... and the paste secret separately as X-Update-Token: .... Claiming is one-way: afterward the account key is the paste's update credential and the old token stops working.

The update_token is revealed exactly once — the server stores only a digest — and authorizes any number of in-place updates while the paste remains anonymous:

curl -X PATCH -H "Authorization: Bearer $UPDATE_TOKEN" \
  -F "file=@plan.html" https://pastehtml.dev/api/pastes/$TOKEN

Updates accept the same two body forms as creation and return 200 with the refreshed { token, title, custom_subdomain, folder, owner, account_paste, password_protected, views_count, live_url, url, raw_url, render_url, markdown_url }, 403 for a wrong or missing update token or an account key that does not own the paste, and 404 for an unknown paste. Paste publish/update endpoints are rate limited per IP at 20 requests per minute and 1,000 per day; folder API endpoints also require an account key and are rate limited per IP.

Agents discover all of this on their own: the full integration guide lives at /llms.txt (also pointed to from the homepage, both visibly and in an HTML comment for raw fetchers). Telling an agent "publish this on pastehtml.dev" is enough.

Stack

• Ruby on Rails 8.1 · PostgreSQL · Hotwire (Turbo + Stimulus)
• Tailwind CSS v4 (cssbundling) · esbuild (jsbundling) · Yarn 4
• Tooling via mise, PostgreSQL via Docker Compose
• Comic-book design: Bangers display type over Inter, halftone textures, ink-outlined panels with hard offset shadows
• Installable PWA: manifest + minimal network-first service worker with an offline fallback page (pastes themselves are never cached)
• SEO via meta-tags (OG/Twitter cards with a branded OG image, canonical, noindex on paste pages) and comic-styled static error pages

Development

mise run dev        # starts postgres (docker), installs deps, prepares db, runs bin/dev

Or step by step:

mise run docker:start   # postgres on localhost:5435
mise run deps           # bundle install + yarn install
mise run db:prepare
bin/dev                 # rails server + js/css watchers on port 3000

Tests and lint

mise run test   # rails test
mise run lint   # rubocop + brakeman

Deployment

Deploys with Kamal from GitHub Actions (the "Kamal Run" workflow) to a single server: the app container plus a postgres 18 accessory. db/production.sql creates the Solid Cache/Queue databases on the accessory's first boot. Pastes are served from <token>.pastehtml.dev subdomains, so the proxy routes the wildcard with a Cloudflare Origin CA certificate (wildcards can't get Let's Encrypt certs over HTTP-01).

One-time setup:

1. Cloudflare (free plan): add a proxied A record for pastehtml.dev, www, and a proxied wildcard * record, all pointing at the server. Set SSL/TLS mode to Full (strict). Create an Origin Server certificate for pastehtml.dev, *.pastehtml.dev and keep the PEM pair.
2. Repository Actions secrets: SERVER_IP, SSH_PRIVATE_KEY (root access to the server), RAILS_MASTER_KEY (from config/master.key), POSTGRES_PASSWORD, CLOUDFLARE_ORIGIN_CERTIFICATE and CLOUDFLARE_ORIGIN_KEY (the Origin CA PEM pair). The container registry (ghcr.io) authenticates with the workflow's own GITHUB_TOKEN.
3. Run the Kamal Run workflow with the command setup once (provisions postgres + proxy), then with deploy for every release.

For local runs of kamal commands, put the Origin CA pair in .kamal/certs/origin.pem / origin-key.pem (gitignored), export SERVER_IP and POSTGRES_PASSWORD, and remove the GHA builder cache block from config/deploy.yml if you need to build the image locally.