# sync.day

> sync.day is a free tool for finding a time that works for everyone. You describe the plan, get one short link, and send it to the group. Each person opens the link, taps the start times they can make, and the page ranks the times by how many people are free. No sign-up, no app, nothing to install.

sync.day (https://sync.day) is a free scheduling tool: one link, no sign-up, ranks candidate start times by how many people are free. It is also a public MCP server so AI assistants can create events and fill in availability.

## How it works

1. **Create the event** — Say what you’re planning, or fill in the dates, the hours and how long it takes. You get a link like sync.day/calm-otter-4821.
2. **Send the link** — Paste it in the group chat. Everyone opens it, types a name once and taps the times they can make. No account needed.
3. **Pick the time** — The page ranks the start times by how many people are free and shows who picked what. When it’s clear, the organizer settles it with one tap.

## Pages

- [Home](https://sync.day/): create an event and get the link
- [MCP server](https://sync.day/mcp): endpoint, tools, setup for Claude / Cursor / ChatGPT / curl
- [Full reference for language models](https://sync.day/llms-full.txt)

## MCP

- Endpoint: `https://sync.day/mcp/mcp` (Streamable HTTP, stateless, no login, no API key, 60 requests/minute per IP)
- `create_event`: Create an event; returns the share link, organizer link and adminKey
- `parse_event_text`: Turn a sentence (“dinner next Saturday afternoon, 3 hours”) into create_event input without creating anything
- `get_event`: Read an event: settings, candidate start times per day, who responded, the top 10 start times, the times everyone can make with their votes, and the decided time
- `submit_availability`: Save the start times one person can make (people are matched by identity; the same identity overwrites); returns the updated ranking
- `vote_time`: Set every start one person accepts (matched by identity; any number, resubmitting replaces the set; they must have saved times first)
- `decide_time`: Organizer settles the time (needs adminKey; null reopens); picking and voting lock afterwards
- `remove_participant`: Organizer removes a participant (needs adminKey)
- `update_event`: Organizer edits the settings (needs adminKey; omitted fields stay as they are)

## Languages

Home:
- [简体中文](https://sync.day/zh-CN)
- [繁體中文](https://sync.day/zh-TW)
- [English](https://sync.day/en)
- [日本語](https://sync.day/ja)
- [한국어](https://sync.day/ko)

MCP page:
- [简体中文](https://sync.day/zh-CN/mcp)
- [繁體中文](https://sync.day/zh-TW/mcp)
- [English](https://sync.day/en/mcp)
- [日本語](https://sync.day/ja/mcp)
- [한국어](https://sync.day/ko/mcp)

## Not indexed

Event pages (`https://sync.day/<adjective>-<noun>`) are private links: unlisted and `noindex`.