Migrate from Klaviyo to Unitpost

Before you start

• A Klaviyo private API key with Read-Only access: Settings → API keys → Create Private API Key, then Read-Only Key. Owners, Admins and Managers can create one. The six-character public key (site ID) can't read your data.
• Klaviyo shows a private key once; copy it before closing the dialog.
• If you text contacts: SMS on Unitpost is on paid plans only, and marketing texts need consent on record per contact.
• A Unitpost API key for your app with emails:send, plus contacts:write and segments:write if your signup form adds contacts, created in API keys.
• A second Unitpost key for the migration steps, with templates:write and webhooks:manage, saved as UNITPOST_MIGRATION_KEY. Keep it out of your app and revoke it once the move is done.
• Access to your DNS host.

The cut-over plan

Klaviyo keeps sending until the last step, so there is no gap in delivery.

1. 1

   Run the Migration Assistant

   Paste the Read-Only key in Settings → Migration. The preview counts what comes over and lists what doesn't: profiles with no email, never-subscribed profiles, your flows, large or inactive segments, and templates whose tags need review. Suppressions are written before contacts, so bounced and blocked addresses land suppressed.

2. 2

   Verify your domain

   Open Domains and publish the records shown: MX and SPF on unitpost.<your domain> and a DKIM TXT under _domainkey. They don't replace Klaviyo's records, so both stay authenticated while you switch. Keep your single _dmarc record.

3. 3

   Review tags and publish

   {{ first_name }} is now {{first_name}}, {{ person|lookup:'Favorite Color' }} becomes the imported field {{favorite_color}}, and {% unsubscribe %} becomes a link to {{unsubscribe_url}}. Filters such as |default:'friend' are dropped. Unitpost fills flat {{name}} placeholders only, so {% if %} and {% for %} blocks, event data and tags such as {% web_view %} or {{ organization.name }} stay as written for you to rewrite. Publish with PATCH /api/v1/email/templates/{id}.

4. 4

   Rebuild segments and flows

   Recreate the segments that should keep updating in Segments as dynamic segments on contact fields. Rebuild each flow in Automations if your workspace has early access; until then, send from your code when the event happens, with POST /api/v1/email.

5. 5

   Point signups and events at Unitpost

   Klaviyo forms keep adding profiles to Klaviyo. Send signups from your own form with POST /api/v1/contacts and add the contact to a segment where you used a list. Klaviyo's profile import upserts; here an existing contact answers 409, and PATCH /api/v1/contacts/{id or email} updates it. Events you sent to Klaviyo to start flows become direct sends.

   signup.ts

   // Before: Klaviyo
   const klaviyo = {
     Authorization: "Klaviyo-API-Key " + process.env.KLAVIYO_PRIVATE_KEY,
     revision: "2026-10-15",
     "content-type": "application/vnd.api+json",
   };
   const res = await fetch("https://a.klaviyo.com/api/profile-import", {
     method: "POST",
     headers: klaviyo,
     body: JSON.stringify({ data: { type: "profile", attributes: { email: "user@example.com", first_name: "Ada" } } }),
   });
   const { data: profile } = await res.json();
   await fetch("https://a.klaviyo.com/api/lists/" + LIST_ID + "/relationships/profiles", {
     method: "POST",
     headers: klaviyo,
     body: JSON.stringify({ data: [{ type: "profile", id: profile.id }] }),
   });
   
   // After: Unitpost
   import { Unitpost } from "unitpost";
   const unitpost = new Unitpost(process.env.UNITPOST_API_KEY);
   const { error } = await unitpost.contacts.create({ email: "user@example.com", first_name: "Ada" });
   // 409 conflict: the contact already exists. Klaviyo's call upserts; update with contacts.update.
   if (error && error.code !== "conflict") throw new Error(error.message);
   await unitpost.segments.addMember("seg_123", { contact: "user@example.com" });

6. 6

   Check SMS consent before texting

   Numbers whose opt-in had no date arrived without consent. Record consent where the contact gave it (POST /api/v1/contacts/{id}/sms-consent) or ask them to confirm with POST /api/v1/contacts/{id}/sms-opt-in-request. Klaviyo SMS opt-outs came over and stay in force.

7. 7

   Add webhooks

   Add each endpoint the preview listed in Webhooks. Klaviyo signs deliveries with Klaviyo-Signature; Unitpost signs each body with a whsec_ secret in svix-id, svix-timestamp and svix-signature, so update your handler.

8. 8

   Test, move traffic, then delete the key

   Send each template with POST /api/v1/email/templates/{id}/test-send and fire POST /api/v1/webhooks/{id}/test at each endpoint. Send your next campaign from Unitpost to a small segment first, then to everyone. Turn each Klaviyo flow off once its replacement runs here, then delete the Klaviyo key.

Before you cancel Klaviyo

• Export the profiles with no email address if you need them; the importer leaves them out.
• Export your suppressed profiles (Audience → Profiles → View suppressed profiles) and import them as suppressions, so complaints shown as unsubscribes stay blocked.
• Write down each flow with its trigger, filters and timing.
• Note the filters of the segments you'll rebuild; only their members came over.
• Delete Klaviyo's DNS records once no mail goes through Klaviyo. Keep _dmarc and Unitpost's records.
• Delete the Klaviyo API key you used for the import.

Facts about Klaviyo checked 2026-11-06. Providers change their APIs and plans; check their docs before you rely on a detail.