Lettr

Tools

• Attach Contacts to Lists

  Attach every combination of 1-1000 contacts and 1-50 audience lists, processing up to 50,000 contact-list pairs and reporting new and existing memberships.

• Bulk Create Audience Contacts

  Create or recognize up to 1000 normalized, deduplicated contacts. Shared properties affect only newly created contacts; list_id applies to all contacts, including those that already exist.

• Cancel Scheduled Email

  Cancel a scheduled email before its delivery time; cancellation is unavailable once processing has begun.

• Create Audience Contact

  Create one audience contact with optional properties and list membership.

• Create Audience Contact With Double Opt-In

  Create an unverified audience contact and irreversibly send an external confirmation email; the contact becomes subscribed only after confirming.

• Create Audience List

  Create a uniquely named audience list for grouping contacts.

• Create Audience Property

  Define a custom contact property with an immutable name and value type. Changing either later requires deleting and recreating the property.

• Create Audience Segment

  Create a dynamic audience segment whose condition groups are ANDed while conditions inside each group are ORed.

• Create Audience Topic

  Create a public or private subscription topic with an immutable opt-in or opt-out default.

• Create Domain

  Register a sending domain and return the DNS configuration needed to verify it.

• Create Template

  Create and publish an email template from either custom HTML or Topol editor JSON, extracting its merge tags.

• Create Webhook

  Create an active event webhook using no authentication, HTTP Basic credentials, or OAuth 2 client credentials.

• Delete Audience Contact

  destructive

  Permanently delete one audience contact and its associated memberships.

• Delete Audience Lists

  destructive

  Permanently delete between 1 and 50 audience lists in one request.

• Delete Audience Property

  destructive

  Permanently delete a custom contact-property definition.

• Delete Audience Segment

  destructive

  Permanently delete one dynamic audience segment.

• Delete Audience Topic

  destructive

  Permanently delete one audience subscription topic.

• Delete Domain

  destructive

  Permanently remove a sending domain from Lettr and SparkPost so it can no longer send email.

• Delete Template

  destructive

  Permanently delete an email template and all of its versions.

• Delete Webhook

  destructive

  Permanently remove a webhook so Lettr stops delivering events to it.

• Detach Contacts from Lists

  Detach every combination of 1-1000 contacts and 1-50 audience lists, reporting removed and absent memberships.

• Get Audience Contact

  Retrieve one contact's email, status, custom properties, list memberships, and topic subscriptions by ID.

• Get Audience List

  Retrieve one audience list and its current contact count by ID.

• Get Audience Property

  Retrieve one custom contact-property definition and its fallback value.

• Get Audience Segment

  Retrieve one dynamic segment's list restriction, complete AND-of-OR condition definition, and cached contact count.

• Get Audience Topic

  Retrieve one subscription topic's defaults, visibility, and current contact count.

• Get Campaign

  Retrieve one campaign's name, subject, sender and reply-to configuration, schedule, rendered HTML, lifecycle state, recipient counts, and engagement statistics. The campaign's audience definition is not returned.

• Get Domain

  Retrieve one sending domain's send readiness, DNS records, provider detection, and verification status.

• Get Email

  Retrieve a sent email's delivery state, recipients, schedule metadata, and events by request ID. The configurable event date range defaults to the last 10 days, not the email's complete event history.

• Get Scheduled Email

  Retrieve a scheduled email's current state and events by transmission ID, including after it has been processed.

• Get Template

  Retrieve an email template's metadata, active HTML or editor JSON content, and version counts by slug.

• Get Template Merge Tags

  Return required and optional merge tags for a template's active or specified version before sending with substitution data.

• Get Webhook

  Retrieve one webhook's target, enabled state, event selection, authentication mode, and latest delivery status.

• List Audience Contacts

  Return one cursor-controlled page of contacts, optionally filtered by search text, status, list, or segment.

• List Audience Lists

  Return one cursor-controlled page of audience lists with each list's contact count.

• List Audience Properties

  Return one cursor-controlled page of custom contact-property definitions and fallback values.

• List Audience Segments

  Return one cursor-controlled page of dynamic audience segments, including their complete AND-of-OR condition definitions, optionally filtered by list.

• List Audience Topics

  Return one cursor-controlled page of subscription topics with defaults, visibility, and contact counts.

• List Campaign Events

  Return one cursor-controlled page of a campaign's delivery and engagement events, with event, recipient, and time filters. An empty items page can still have a next_cursor; continue until next_cursor is null.

• List Campaigns

  Return one cursor-controlled page of campaigns with complete delivery and engagement statistics, optionally filtered by lifecycle status.

• List Domains

  Return all sending domains with approval, DNS verification, and send-readiness status.

• List Email Events

  Return one cursor-controlled page of delivery and engagement events across sent emails, with event, recipient, transmission, bounce, and date filters.

• List Projects

  Return one cursor-controlled page of Lettr projects and their IDs for use with template operations.

• List Sent Emails

  Return one cursor-controlled page of sent emails, optionally filtered by recipient and date range.

• List Templates

  Return one cursor-controlled page of email templates for a project or the team's default project.

• List Webhooks

  Return all event webhooks with target, enabled state, event selection, authentication mode, and latest delivery status.

• Publish Template Version

  Create and activate a new version of an existing email template from exactly one of HTML or Topol editor JSON, optionally renaming the template atomically.

• Schedule Campaign

  Schedule a campaign for future delivery or reschedule it. The campaign dispatches automatically at that time unless it is unscheduled first.

• Schedule Email

  Create a transactional email scheduled 5 minutes to 3 days in the future; it remains cancellable until processed.

• Send Campaign

  Immediately and irreversibly start sending a sendable draft campaign to its resolved audience. Only call after confirming the campaign's audience, subject, sender email, and content. A successful 202 response transitions the campaign asynch

Works well with

How Switchy teams use it

Starter prompts

More other MCPs

• LeverLever
• Lightspeed Retail X-SeriesLightspeed Retail X-Series
• LILT MCPLILT MCP
• Linear MCPLinear MCP
• LinguapopLinguapop
• Linguin AILinguin AI
• LinkedInLinkedIn
• Linkedin AdsLinkedin Ads
• LinkhutLinkhut
• LinklyLinkly
• LinkTwinLinkTwin
• LinkupLinkup

See all other MCPs →