Calends

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

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

_{Overview and subscription timeline · Fictional demo data}

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, postpaid billing, separate bill/payment tracking, advance charging and cancellation deadlines.
• Usage meters — track per-period usage or cumulative readings in any unit, with shared meters across subscriptions, usage metrics, aligned charts and usage in charge records.
• Billing history — keep price, plan and region changes, gaps and overlapping subscriptions; upgrades can credit the unused part of the old plan. See total spent, actual monthly cost and every charge.
• Transfers and split payments — count second-hand takeovers and resales in net cost, and split a charge across multiple payment methods.
• 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, per-period receipts with skipped-period collection, prepayments and waivers, overdue tracking and exit refunds; the member sheet uses a monthly period grid with receipt details on click, prepayments and waivers, while people have private avatars, custom colors and a separate account for each plan.
• Reports and calendar — spending trends, a daily heatmap with optional 3D bars, cash vs. accrual, funding flows, region and category profiles, 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.
• Import external ledgers — preview and import CSV files, ZIP backups and databases from Wallos and other services in your browser.
• Public page editor — arrange widgets on a grid canvas and customize the header of your read-only public page.
• 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.

Want a look first? Try the live demo.

Deploy to Cloudflare, add a long random SETUP_TOKEN secret to the Worker, then open its URL, enter the token and set your password. To deploy from source, see the Cloudflare guide.

curl -fsSL https://raw.githubusercontent.com/imetn/calends/main/docker/compose.prebuilt.yml -o compose.yml
docker compose up -d
docker compose logs calends

Open http://localhost:8787/, enter the setup token from the logs and set your password.

On Debian or Ubuntu with systemd:

curl -fsSL https://calends.date/install.sh | sudo bash

Calends starts on 127.0.0.1:8787; point your own reverse proxy at it. Run the same command to upgrade.

For upgrades, HTTPS, configuration and other options, see the self-hosting guide.

Ask “What renews next week?”, “How much did I spend this year?” or “Netflix went up to $17.99 from today.” Calends provides 36 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.

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.

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.

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.

The Latin letters and numerals use Xiaomi's MiSans Latin, bundled unmodified in app/public/fonts/ under the MiSans license; it is not covered by the MIT License and may not be modified or redistributed on its own.