--- title: "Connect CalendarLink to Lettr - APIANT.ai" description: "When \"New Upcoming Event\" fires in CalendarLink, your agent runs \"Add contact\" in Lettr." canonical: "https://apiant.ai/connect/calendarlink-to-lettr" --- # Connect CalendarLink to Lettr When **New Upcoming Event** fires in [CalendarLink](https://apiant.ai/connections/calendarlink), your agent runs **Add contact** in [Lettr](https://apiant.ai/connections/lettr). Describe the whole flow and it is built, tested on every scenario and kept running. CalendarLink **1** trigger CalendarLink **8** actions Lettr **11** actions What the catalog holds today. Ask for anything missing and your agent reads the API documentation and adds it. ## What do you want CalendarLink and Lettr to do together? Give your AI client this address. `https://mcp.apiant.ai` One connection does both: ask your client to act in an app once, or have it build an automation that keeps running. Any client that takes a remote MCP server. Nothing to install. Create your free account, then sign in once in your browser. ### Set it up in your client ### Claude Code Run this in the directory you want to work in. `claude mcp add --transport http -s project apiant-ai https://mcp.apiant.ai` Start Claude Code there, approve the server, and sign in in the browser page it opens. [Claude Code guide (opens in a new tab)](https://apiant.ai/docs/mcp/claude-code) ### Claude, web and desktop Open Customize, then Connectors, then Add custom connector, and paste the address. On Team and Enterprise an owner adds it first. [Setup guide (opens in a new tab)](https://apiant.ai/docs/mcp) ### Cursor Add the address to your MCP configuration as a server URL. Cursor signs you in in your browser. [Setup guide (opens in a new tab)](https://apiant.ai/docs/mcp) ### Zed Open Settings, then AI, then MCP Servers, then Add Server, then Add Remote Server. [Setup guide (opens in a new tab)](https://apiant.ai/docs/mcp) ### Codex and the ChatGPT desktop app Open Settings, then MCP servers, then Add server, and choose Streamable HTTP. From the terminal, Codex takes the address with its own add command and then signs you in. [Setup guide (opens in a new tab)](https://apiant.ai/docs/mcp) ### Any other MCP client Paste the address where the client asks for a remote MCP server URL, and name the server apiant-ai where it lets you. APIANT's skills reach the client over the same connection. [Setup guide (opens in a new tab)](https://apiant.ai/docs/mcp) Example flows ## What CalendarLink can start in Lettr - When **New Upcoming Event** in CalendarLink then **Add contact** in Lettr - When **New Upcoming Event** in CalendarLink then **Add contact to list** in Lettr Starting points drawn from the triggers and actions in the catalog today. Describe the flow you need, at any depth, and your agent builds it and tests every scenario before it ships. Everything your agent can do with CalendarLink and Lettr ## Triggers and actions 1 trigger · 19 actions - Trigger **New Upcoming Event** Triggered when a new upcoming event is added to your CalendarLink organisation. - Action **Create New Event** Creates an event in a CalendarLink collection and returns its add-to-calendar link. Times use the format 2026-09-01 09:00:00. Optionally turns on RSVP with a deadline, attendee limit and notification settings. - Action **Find Event** Searches your CalendarLink events for one whose title contains the text you give, and returns the first match with its add-to-calendar link, times and RSVP counts. - Action **List Contacts** Returns a page of the contacts in your CalendarLink organisation, 15 per page, along with how many pages there are. - Action **List Event Collections** Returns every event collection in your CalendarLink organisation, with each collection's ID, name, description, public link and event count. - Action **List Event Registrations** Returns a page of the people who signed up for one CalendarLink event, 15 per page. The event must have RSVP turned on. - Action **List Past Events** Returns a page of your CalendarLink events that have already finished, 15 per page, newest first. - Action **List Upcoming Events** Returns a page of your CalendarLink events that have not happened yet, 15 per page. - Action **Update Event Collection** Changes the settings of one CalendarLink event collection — its name, description, appearance, what visitors can add and whether sign-up is required. Only the fields you fill in are changed; the rest keep their current values. - Action **Add audience list** Creates a new audience list in Lettr with the given name and returns the created list. - Action **Add contact** Adds a new contact to your Lettr audience, optionally placing it on a list, setting custom properties, and sending a double opt-in confirmation email. - Action **Add contact to list** Adds an existing contact to one of your audience lists. Succeeds whether the contact was newly added or was already on the list. - Action **Add template** Creates a new email template in Lettr from HTML or Topol editor JSON content, and publishes its first version with the merge tags found in the content. - Action **Delete contact** Permanently deletes a contact from your Lettr audience. - Action **Get contact** Returns a single audience contact, including its subscription status, custom properties, lists and topics. - Action **Get template** Returns a single email template by its slug, including its HTML, editor content, purpose, status and version details. - Action **List audience lists** Returns all audience lists in your Lettr team, with each list's name and contact count. - Action **List contacts** Returns the contacts in your Lettr audience, optionally narrowed by a search term, subscription status, list or segment. - Action **List templates** Returns the email templates in a Lettr project, optionally limited to one folder or to transactional or campaign templates. - Action **Update contact** Updates an existing contact in your Lettr audience, changing its email address, subscription status or custom properties. Fields left blank are not changed. ## Each app on its own - [ **CalendarLink** CalendarLink creates add-to-calendar links to any calendar service and make sure your users don't forget...](https://apiant.ai/connections/calendarlink) - [ **Lettr** Lettr is a email API for artisans, send transactional emails using HTML or stored templates.](https://apiant.ai/connections/lettr) Reviews ## What our customers say ## More from CalendarLink - [ **CalendarLink to Stripe** Stripe is a payment processing platform for online businesses.](https://apiant.ai/connect/calendarlink-to-stripe) - [ **CalendarLink to HubSpot** HubSpot is your all-in-one stop for all of your marketing software needs.](https://apiant.ai/connect/calendarlink-to-hubspot) - [ **CalendarLink to Salesforce** Salesforce is a leading enterprise customer relationship management (CRM) platform.](https://apiant.ai/connect/calendarlink-to-salesforce) - [ **CalendarLink to Slack** Slack is a messaging platform for teams. Post messages, manage channels, users, reminders, and react to...](https://apiant.ai/connect/calendarlink-to-slack) - [ **CalendarLink to Google Sheets** Google Sheets](https://apiant.ai/connect/calendarlink-to-google-sheets) - [ **CalendarLink to Gmail** Gmail is Google’s email service, featuring spam protection, search functions, and seamless integration with...](https://apiant.ai/connect/calendarlink-to-gmail) ## More into Lettr - [ **HubSpot to Lettr** HubSpot is your all-in-one stop for all of your marketing software needs.](https://apiant.ai/connect/hubspot-to-lettr) - [ **Salesforce to Lettr** Salesforce is a leading enterprise customer relationship management (CRM) platform.](https://apiant.ai/connect/salesforce-to-lettr) - [ **Slack to Lettr** Slack is a messaging platform for teams. Post messages, manage channels, users, reminders, and react to...](https://apiant.ai/connect/slack-to-lettr) - [ **Google Sheets to Lettr** Google Sheets](https://apiant.ai/connect/google-sheets-to-lettr) - [ **Gmail to Lettr** Gmail is Google’s email service, featuring spam protection, search functions, and seamless integration with...](https://apiant.ai/connect/gmail-to-lettr) - [ **Google Calendar to Lettr** Google Calendar is a time management tool providing scheduling features, event reminders, and integration...](https://apiant.ai/connect/google-calendar-to-lettr) Questions ## CalendarLink and Lettr, answered ### ### What can start an automation from CalendarLink? Any of CalendarLink's 1 trigger in the catalog, including New Upcoming Event. Describe the moment in plain language and your agent picks the right one. ### ### What can your agent do in Lettr when something happens in CalendarLink? Any of Lettr's 11 actions, including Update contact, Add audience list, Add contact and Add contact to list. Your agent maps the data both ways and tests every scenario before it ships. ### ### Can it also run from Lettr to CalendarLink? Lettr has no triggers in the catalog today, so automations start in CalendarLink. If you need the other direction, ask: your agent reads Lettr's API documentation and adds it. ### ### Do I have to build a connector for CalendarLink or Lettr? No. Both are in the catalog with their triggers and actions. You describe the automation; your agent builds it, tests every scenario and keeps it running. ### ### Can my AI client use CalendarLink and Lettr without building an automation? Yes. With your AI client connected to APIANT, ask it to do something in either app once and it runs that action on the spot. Ask for an automation and your agent builds it, tests every scenario and keeps it running. One connection covers both. ### ### What happens when something fails? Your agent works that out for you. It plans the failure paths along with the happy path, then tests every scenario before it ships. ### ### Is there a free plan? Yes. Every plan includes the agent, including free, and building from your own AI client spends no assistant credits.