Calends

Track subscription charges, shared payments and prepaid balances on your own server.

Website · Live demo · Quick start · AI & MCP · 简体中文

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Billing and payment history

Track what you pay, when it renews, and who owes you. Calends brings subscriptions, shared plans and prepaid balances into one private, single-owner ledger, with an optional read-only public page and AI access through MCP.

• Flexible billing — monthly, yearly, custom cycles and lifetime purchases, with trials, intro prices, bonus periods, pauses, advance charging and cancellation deadlines.
• Billing history — keep price, plan and region changes, gaps and overlapping subscriptions. See total spent, actual monthly cost and every charge.
• Multiple currencies — historical exchange rates for past charges, current rates for forecasts, and your choice of display currency.
• Balances and shared plans — track prepaid credit and gift cards, estimate when balances run out, and manage payments for friends. Shared plans have dated collection rules, member overrides, independent coverage periods, overdue tracking and exit refunds; people have private avatars and a separate account for each plan.
• Reports and calendar — spending trends, cash vs. accrual, prepaid value, cancellation savings, subscription checkups and a shareable year in review. Includes month/year calendars and a private ICS feed.
• Search — find Chinese names by full pinyin, initials or mixed syllables in the subscription list, command palette and pickers.
• Renewal reminders — email, Telegram, Lark/Feishu, DingTalk, WeCom, Slack, Discord, Bark, ntfy, ServerChan and custom webhooks.
• AI access — query and update your ledger from an MCP-compatible assistant, with scoped tokens and previews for write operations.
• Storage and access — password and passkey sign-in, remote device sign-out, optional public sharing with server-side masking, JSON backup/restore and CSV import/export. Available in 14 languages.

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Quick start

Try the live demo to explore before deploying. It is shared by all visitors and resets daily; external notifications are disabled.

Open Calends at / and sign in at /login. After signing in, / redirects to your configured start page, defaulting to /overview. Public sharing is optional: enable it in Settings to make the read-only page available at /public. See routes and login redirects for details.

Cloudflare Workers

Use one-click deployment with Workers and D1, or deploy from source:

git clone https://github.com/imetn/calends
cd calends
npm ci
npx wrangler login
node scripts/wrangler.mjs secret put SETUP_TOKEN
npm run deploy

Use a long random string for SETUP_TOKEN. The deploy command builds the app, provisions D1 on first deployment and applies migrations. Open https://<your-worker>.workers.dev/, enter the token on the login page and set your password.

Docker

Run the prebuilt image directly:

docker run -d --name calends -p 8787:8787 -v calends-data:/data xizozhe/calends:latest
docker logs calends

Open http://localhost:8787/ and use the setup token printed in the logs on the login page. The named volume calends-data persists SQLite data at /data. You can also use ghcr.io/imetn/calends:latest. For production, pin a version tag such as 1.8.0 instead of latest.

Alternatively, build from source with Compose. From a source checkout, Compose (in docker/) builds the included Dockerfile and starts the app:

cd docker
docker compose up -d --build
docker compose logs calends

The Compose configuration persists SQLite data in a named volume mounted at /data. Building locally does not require a published Calends image or a Cloudflare account. See the Docker guide for image registries, upgrades and Compose options.

For public access, enable HTTPS through a reverse proxy and set TRUST_PROXY=1. Add a passkey after setup in Settings → Security.

See the self-hosting guide for custom domains, configuration, email reminders, subpath deployment and a prompt to delegate deployment to your AI agent.

AI & MCP

Ask “What renews next week?”, “How much did I spend this year?” or “Netflix went up to $17.99 from today.” Calends provides 32 tools over a stateless MCP endpoint at /mcp using Streamable HTTP.

On the AI access page (/connect), create a read-only or read/write token, then connect your client. Opening /mcp in a browser takes you to this page; MCP clients use the /mcp endpoint:

Claude Code

claude mcp add --transport http calends https://your-domain/mcp --header "Authorization: Bearer <token>"

Codex

export CALENDS_TOKEN='<token>'
codex mcp add calends --url https://your-domain/mcp --bearer-token-env-var CALENDS_TOKEN

Keep CALENDS_TOKEN available in the environment that launches Codex. Tools cover subscriptions, spending, trends, receivables and insights, plus changes to prices, plans, status and payments. Every write tool supports dry_run; AI access can be turned off in Settings.

Contributing

Bug reports, translations and pull requests are welcome. See CONTRIBUTING.md for local setup, checks and contribution guidelines.

Start with the architecture and code standards before changing a subsystem. Coding agents use AGENTS.md; CLAUDE.md imports the same instructions.

Built with React 19, Vite, HeroUI / React Aria, shadcn/ui and Cloudflare Workers + D1 (SQLite). Billing, exchange rates and other domain logic are shared between the browser and Worker in shared/.

Translations live in shared/locales/<locale>/<namespace>.json, with English and Simplified Chinese as the source languages.

About the name

Calends were the first day of every Roman month, when accounts were settled and debts called in. It is also where the word calendar comes from.

License

Calends is open source under the MIT License; see LICENSE. You may use, modify and redistribute it, including commercially, provided you retain the copyright and license notices in copies or substantial portions of the software. If you fork Calends, please use a distinct name and credit Calends as the upstream source so users can distinguish your version from this project.