App

Lettr integrations

Connect Lettr to any other app, or use it from your AI client over MCP. Lettr is a email API for artisans, send transactional emails using HTML or stored templates. Track engagement and deliverability.

Connects with an API keylettr.com
11 actions

What the catalog holds today. Ask for anything missing and your agent reads the API documentation and adds it.

Build solutions, not workarounds.

What do you want to automate with Lettr?

Ask the assistant

You'll sign in before anything runs. What you typed comes with you.

Connect your AI client

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)
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)
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)
Zed

Open Settings, then AI, then MCP Servers, then Add Server, then Add Remote Server.

Setup guide (opens in a new tab)
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)
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)

Popular

Lettr with the apps people pair it with most

Pair it

Connect Lettr with another app

What your agent can do with Lettr

Triggers and actions 11 actions

  • 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.

Reviews

What our customers say

Questions

Lettr, answered

Is there a Lettr MCP server?

APIANT's MCP server at https://mcp.apiant.ai works with Lettr. Add that address to any AI client that takes a remote MCP server and sign in once in your browser. Your client can then run Lettr actions on demand, or have APIANT build, test and run automations that use Lettr. Nothing to install.

What can your agent do in Lettr?

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 I use Lettr directly from Claude, ChatGPT or Cursor?

Yes. Connect your AI client to APIANT once and it works with Lettr two ways. Ask it to do something in Lettr 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 on its own. A one-off action uses your plan's tasks the same way an automation step does.

Do I need to write code against the Lettr API?

No. APIANT connects to the Lettr API for you, with your Lettr API key. Describe what you want in plain language and your agent builds it on the Lettr triggers and actions in the catalog. If you need an endpoint that is not there yet, your agent reads the Lettr API documentation and adds it.

Which apps can Lettr connect to?

Any app in the catalog; the list on this page pairs Lettr with each of them. If the other app is missing, point your agent at its API documentation and it builds the connector.

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.