Migrate from Mailchimp to Relayly

Why teams leave Mailchimp

Audience-based pricing surprises. Mailchimp bills by audience size, not send volume. Cleanups don't reduce the bill until you re-archive.
Limited segment logic. Mailchimp's segment builder maxes out at 5 conditions. Predicate-based DSL has no such limit.
Slow at scale. Many teams report multi-second segment evaluation above 100k members.
API is an afterthought. Mailchimp's REST API exists but isn't the primary interface. Relayly is API-first.

What carries across

Mailchimp concept	Relayly equivalent	Auto-migrates?
Audiences	`lists`	Yes — names + opt-in setting.
Members + tags	`contacts + custom fields`	Yes — Mailchimp tags become contact tags directly.
Segments	`Predicate-based segments`	Mailchimp DSL → Relayly predicates. Most rules translate; we flag the rest.
Templates	`email_templates`	Drag-drop preserved via MJML re-render. Classic templates carry as HTML.
Customer Journeys	`Flows`	Step-by-step automation translates to flow nodes.
Forms (Mailchimp signup forms)	`Signup forms`	Hosted forms migrate; embedded JS forms get a snippet swap.

The codebase swap

API shapes are similar enough that find/replace handles most call sites. The key differences:

// Mailchimp Marketing API
import mailchimp from "@mailchimp/mailchimp_marketing";
mailchimp.setConfig({
  apiKey: process.env.MAILCHIMP_API_KEY,
  server: "us1",
});

await mailchimp.lists.addListMember("<list_id>", {
  email_address: "user@example.com",
  status: "subscribed",
  merge_fields: { FNAME: "Alex" },
});

// Relayly Node SDK
import Relayly from "@relayly/node";
const r = new Relayly({ apiKey: process.env.RELAYLY_API_KEY });

await r.contacts.upsert({
  email: "user@example.com",
  list:  "<list_id>",
  fields: { first_name: "Alex" },
});

Customer Journeys → Flows

Mailchimp's Customer Journey builder maps cleanly to Relayly Flows. The migrator walks each journey graph and translates each node:

Trigger → flow trigger (event, list join, custom field change)
Send email → send action with a template reference
Wait → delay node (preserves the duration)
If/else → branch node with the same predicate
Tag / untag → tag mutation action

Branched journeys with custom decision logic are flagged — usually 5-10 min of manual review per journey.

The cutover playbook

Run the export script. It's read-only against Mailchimp and re-runnable.
Review the manifest. Anything flagged as "needs review" gets a copy-paste remediation snippet.
Apply to Relayly. Idempotent SQL + REST imports. Re-run safely.
Dual-send for a week. Compare inbox rates at Gmail / O365 / Yahoo through the dashboard.
Flip the API key. Search-and-replace your codebase, deploy, monitor 24h.
Pause Mailchimp. Don't delete the account — keep it for 30 days as an unsubscribe-list reciprocity reference.
After 30 quiet days, terminate Mailchimp. You're done.

Pricing-side check

Volume	Mailchimp	Relayly	Annual delta
10k contacts, 50k sends/mo	$32/mo (Standard)	$25/mo	+ $84/year
50k contacts, 200k sends/mo	$255/mo	$100/mo	+ $1,860/year
200k contacts, 800k sends/mo	$700/mo	$130/mo	+ $6,840/year

Mailchimp Standard pricing as of 2026-05 from mailchimp.com/pricing. The contact-based pricing is the dominant cost driver — Relayly bills by send volume only.

Start the migration

Start free