Working in Integrations

Letterhead connects to the tools you already use — your email service provider, CRM, payment platform, and workspace apps. This page covers everything you can do in the Integrations area, and what each connection does and doesn’t do.

Tip

Curious what the Letterhead assistant can help with? See how the assistant works.

Email service providers (sending)

Create newsletters in Letterhead while sending through Iterable or Mailchimp. Letterhead builds the email; your ESP delivers it.

• What it does: connect an ESP per channel, choose a provider per template, set a separate from address for Iterable, and use Iterable data feeds for per-recipient dynamic content — including personalized images.
• What it doesn’t do: manage your ESP’s own audience settings or billing — those stay in Iterable/Mailchimp.
• Letterhead monitors provider connections, flags broken ones, and auto-resumes paused automations when connectivity is restored. Newsletters sent natively through Mailchimp also appear in your channel with performance metrics automatically — no manual import step needed.

What can Iterable data feeds do?

Connect your Iterable data feeds to a channel once and that dynamic content flows into every newsletter you publish from it — no re-wiring the feed on each send. Any image block can use a data-feed expression instead of a static uploaded image, so each recipient’s email renders a different image at send time, resolved per recipient by the ESP — and the image’s link can be a feed expression too, sending each reader to a different destination. Data feeds may need to be enabled for your account — contact support. See Connect Iterable data feeds to your channel.

The separate Iterable “from” address is optional and must be on a domain verified in Iterable; leaving it blank means the reply address doubles as the sender, as before.

CRM audience sync

Keep contacts synchronized between your CRM and Letterhead at the company level, for HubSpot and Mailchimp.

Stripe

Connect Stripe from your company integrations settings to bring purchase data into Letterhead. Once connected, Stripe purchase events appear in each contact’s activity feed — showing purchase date, amount, and source, with the actual product they bought named rather than only the amount — so you can see who has bought alongside their email engagement history. See Stripe.

• Customer import: switch on customer import and Letterhead pulls your existing Stripe customers into your audience as contacts, then keeps the list current by adding new customers automatically as they appear in Stripe. Imported contacts are tagged so you can find and segment them, and anyone already in your audience is left untouched. This may need to be enabled for your account — contact support. See Connect Letterhead to Stripe.
• Product sync: turn on “Sync Products” and the things you sell flow into your curation pool as ready-to-use content blocks — each carrying its name, description, image, and price — with the catalog kept current automatically as products are added, changed, or retired. See Add Stripe products to newsletters as content blocks.

Shopify

Connect your Shopify store from your company integrations settings by entering your store domain and choosing Connect with Shopify.

• Product sync: turn on “Sync Products” and the things you sell flow into your curation pool as ready-to-use content blocks — each carrying its name, description, photo, and price, and linking readers straight to that product in your store. Your catalog stays current on its own as products are added, repriced, or retired. See Connect Letterhead to Shopify.
• Purchasers as contacts: switch on “Add purchasers as contacts” and buyers from new orders who aren’t already in your audience are added, so their purchases aren’t lost. Orders placed before you switched it on aren’t imported.

Zapier

Connect Zapier with a company-level API key to automate audience work from any Zap: add or update contacts, manage tags, and push articles into your Curations library.

What can Zapier do with my company audience?

Working against your whole company audience rather than a single channel, a Zap can add or update a contact — setting their name and your own custom fields, with contacts matched by email so the same step adds or updates — and apply or remove tags. The “Add or Update Contact” action also accepts an optional Subscriptions line-item field, so you can set a contact’s status on one or more of your channels (Not Subscribed, Subscribed, or Unsubscribed) in the same step, without a separate action. Existing Zaps built on the older per-channel actions keep working — those actions are relabelled Legacy. Company-audience access may need to be enabled for your account — contact support. See Letterhead + Zapier.

Slack

Get notifications about your newsletters in a Slack channel of your choice.

WordPress

Use the Letterhead WordPress plugin to embed subscribe forms or newsletter content on your site. When you curate posts from your WordPress site, the details each post carries can travel with it: any custom field you’ve set up for a channel fills automatically from the matching field on your post, and from the plugin’s settings you can map any WordPress field — a custom field, an Advanced Custom Fields, Meta Box, or Pods field, a category or tag, or a built-in detail like the title or publish date — to a Letterhead custom field. On a multisite network you can set this up for each site. See Map WordPress custom fields to Letterhead.

AI tools (MCP)

Letterhead exposes an MCP server, so AI tools like Claude can query your channels, letters, and performance metrics. Add Letterhead as a custom connector and sign in with OAuth. See Connect AI tools via MCP.

What can a connected AI assistant do?

With an AI client such as Claude Desktop connected, you can ask the assistant to: draft a complete newsletter from a plain-language description — rendered in your channel’s visual identity (brand colors, fonts, logo, and the correct unsubscribe footer), saved as a draft with a direct link to open it in the composer, and deletable from the conversation if it isn’t right (drafting may need to be enabled for your account — contact support); check a draft’s title and status or revise its subject line and preview text; manage your promotions — list them and their schedules, reschedule, pause or reactivate, or edit headline, content, and link (on for every customer); set and retarget performance goals; schedule, edit, or cancel recurring metric reports; check which automations are running, paused, or have errored; pull a company-wide rollup of how your whole audience is performing across every channel; browse your company’s cross-channel curated content; and report how your transactional emails are performing, grouped by tag (transactional email may need to be enabled for your account — contact support).

When drafting a newsletter from a plain-language description, the assistant sources content from your curations — and can pull fresh articles from the web when the pool is thin — and writes in your channel’s established voice.

Not finding what you need?

Some integrations live elsewhere: Google Docs import and the Evvnt events block are in the newsletter composer, Google Ad Manager ad tags can be pasted into an HTML promotion (see How to use HTML Promotions), and the full API supports custom integrations. For anything else, ask the assistant (if you have early access) or contact support.