Integration
Connect Lettr and TESS
When New email event fires in Lettr, your agent runs Create Memory in TESS, or New Memory in TESS to Add contact in Lettr. Describe the whole flow and it is built, tested on every scenario and kept running.
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 Lettr and TESS to do together?
Ask the assistant
Connect your AI client
Give your AI client this address.
https://mcp.apiant.aiOne 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.aiStart 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)Grok
Open grok.com/connectors, choose New Connector, then Custom, and paste the address. Grok signs you in in your browser.
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)Example flows
What Lettr and TESS can do together
From Lettr to TESS
When New email event in Lettr
then Create Memory in TESS
When New email event in Lettr
then Create Memory Collection in TESS
From TESS to Lettr
When New Memory in TESS
then Add contact in Lettr
When New Memory in TESS
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 Lettr and TESS
Triggers and actions 2 triggers · 40 actions
Trigger
New email eventTriggers instantly when Lettr reports an email event, such as a delivery, bounce, open, click, spam complaint or unsubscribe.
Action
Add audience listCreates a new audience list in Lettr with the given name and returns the created list.
Action
Add contactAdds 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 listAdds an existing contact to one of your audience lists. Succeeds whether the contact was newly added or was already on the list.
Action
Add templateCreates 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
Create campaignCreates a draft email campaign in Lettr with its subject, sender, content and audience, ready to send or schedule.
Action
Create webhookCreates a Lettr webhook that sends email delivery and engagement events to a URL.
Action
Delete contactPermanently deletes a contact from your Lettr audience.
Action
Delete webhookDeletes a Lettr webhook so it stops sending events.
Action
Get campaignReturns one Lettr campaign with its settings, audience, status and delivery stats.
Action
Get contactReturns a single audience contact, including its subscription status, custom properties, lists and topics.
Action
Get emailReturns a sent email's details — sender, subject, recipients, delivery state — and all of its delivery, bounce, open and click events.
Action
Get templateReturns a single email template by its slug, including its HTML, editor content, purpose, status and version details.
Action
Get webhookGets one Lettr webhook by ID: its name, URL, event types, whether it is enabled and its last delivery status.
Action
List audience listsReturns all audience lists in your Lettr team, with each list's name and contact count.
Action
List campaignsReturns the email campaigns in your Lettr account, optionally only those with a given status.
Action
List contactsReturns the contacts in your Lettr audience, optionally narrowed by a search term, subscription status, list or segment.
Action
List domainsReturns every sending domain registered in your Lettr account, with its approval status, whether it can send, and its DNS verification state.
Action
List emailsReturns emails sent from your Lettr account in the last few days, optionally filtered by recipient address and date range.
Action
List templatesReturns the email templates in a Lettr project, optionally limited to one folder or to transactional or campaign templates.
Action
Schedule campaignSchedules a Lettr campaign to send at a future time, or moves an already scheduled campaign to a new time.
Action
Schedule emailSchedules a transactional email for delivery at a future time (at least 5 minutes ahead and within 30 days), using your own content or a saved template.
Action
Send campaignSends a draft Lettr campaign to its audience right away. The campaign needs a subject, a sender on a verified domain, and content.
Action
Send EmailSends a transactional email through Lettr to one or more recipients, using your own HTML/text content or a saved template.
Action
Send Email TemplateSends an email using one of your saved Lettr templates, filling its merge variables with the values you provide. Returns the send's request ID and how many recipients were accepted.
Action
Unschedule campaignCancels a scheduled Lettr campaign send and returns the campaign to draft.
Action
Update contactUpdates an existing contact in your Lettr audience, changing its email address, subscription status or custom properties. Fields left blank are not changed.
Trigger
New MemoryTriggers when a new memory is added in Tess, optionally only in one collection.
Action
Create MemoryCreates a Tess memory, optionally inside a memory collection.
Action
Create Memory CollectionCreates a Tess memory collection.
Action
Delete FileDeletes a file uploaded to Tess.
Action
Delete MemoryDeletes a Tess memory.
Action
Execute an AgentSends a message to a Tess agent, waits for it to finish, and returns the generated content.
Action
Execute Long Running AgentStarts a Tess agent without waiting and returns the execution response ID to fetch the result later.
Action
Find Agent DetailsReturns one Tess agent's details, including the input fields it asks for when executed.
Action
Find Agent Execution ResponseReturns the status and generated content of one agent execution.
Action
Find AgentsSearches your Tess agents by text or type and returns their details.
Action
Get FileReturns one file uploaded to Tess.
Action
List FilesLists files uploaded to Tess, newest first by default.
Action
List MemoriesLists Tess memories, optionally only those in one collection.
Action
List Memory CollectionsLists Tess memory collections, optionally filtered by name.
Action
Update MemoryUpdates the text or collection of a Tess memory.
No trigger or action matches that. Ask your agent to add it: it reads the API documentation and builds what you describe.
Each app on its own
Reviews
What our customers say
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Questions
Lettr and TESS, answered
What can start an automation from Lettr?
Any of Lettr's 1 trigger in the catalog, including New email event. Describe the moment in plain language and your agent picks the right one.
What can your agent do in TESS when something happens in Lettr?
Any of TESS's 14 actions, including Create Memory, Create Memory Collection, Update Memory and Execute an Agent. Your agent maps the data both ways and tests every scenario before it ships.
Can it also run from TESS to Lettr?
Yes. When something happens in TESS, your agent can act in Lettr too. This page covers both directions: TESS's triggers and Lettr's actions are listed here as well.
Do I have to build a connector for Lettr or TESS?
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 Lettr and TESS 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.