Mailchimp holds the higher mean on campaign and automation (7.0 vs 6.0; 5 judges lean Mailchimp, 1 tie), deliverability (6.8 vs 3.8; 6 lean Mailchimp), list data control (7.0 vs 4.7; 6 lean Mailchimp), integrations (7.7 vs 5.8; 5 lean Mailchimp, 1 tie) and pricing transparency (5.3 vs 2.0; 6 lean Mailchimp). Klaviyo's higher mean is sovereignty, 1.8 vs 1.5, with 2 judges leaning Klaviyo, 0 leaning Mailchimp and 4 ties; Klaviyo's data residency reads EU optional against Mailchimp's US default. Consent and proof is the genuine split: 5.2 vs 5.5 with 3 judges leaning each way. The weighted totals the table lists — CRM manager 5 vs 6.7, deliverability engineer 5.2 vs 6.3, data-protection officer 3.8 vs 4.6, integrator 4.3 vs 6.2, skeptic 3.3 vs 5.7 — put the higher figure on Mailchimp's side. No overall winner is declared: the lean differs by criterion, and that difference is the answer.
Choose Klaviyo if
You need the option to keep contact data in the EU — Klaviyo's data residency is recorded as EU optional, Mailchimp's as US default.
Your contract terms must allow hosting wherever the vendor or its subprocessors maintain facilities — Klaviyo's processing agreement permits that, while Mailchimp's captured pages show US hosting as the fixed default with no EU option on those pages.
You weight sovereignty heavily in your scoring — Klaviyo's sovereignty mean is 1.8 against Mailchimp's 1.5, with 2 judges leaning Klaviyo, 0 leaning Mailchimp and 4 ties.
Your legal screen flags vendors whose subprocessor exposure is recorded as US Cloud Act — Mailchimp's attribute reads US Cloud Act; Klaviyo's is recorded as unknown.
Choose Mailchimp if
You need deliverability you can check before committing — deliverability means run 6.8 vs 3.8, with 6 judges leaning Mailchimp and 0 leaning Klaviyo.
You must be able to take your whole list with you — Mailchimp documents a whole-account export as a zip, and list data control runs 7.0 vs 4.7 with 6 judges leaning Mailchimp.
You need published plan prices before signing — the captured Klaviyo pages state no paid prices, only scaling by contact count and channels with a custom enterprise quote; pricing transparency runs 5.3 vs 2.0 with 6 judges leaning Mailchimp.
Your stack runs on Salesforce — Mailchimp states a two-way Salesforce sync among its 300+ integrations, and integrations leans 5 judges to Mailchimp with 1 tie.
You build branching customer journeys — Mailchimp's journey builder offers conditional and percentage splits, and campaign and automation runs 7.0 vs 6.0 with 5 judges leaning Mailchimp and 1 tie.
Read this comparison as one judge. Each weighs the same scores by what they care about.
The Integrator
Has to wire this into a stack that already exists. Wants a documented API with rate limits, webhooks that retry, a sandbox and a deprecation policy. Treats a partner-form integration page as a missing API, and reads "Zapier supported" as an outsourced one.
Klaviyo
Mailchimp
This judge's pick
Criterion by criterion
Campaigns & automation
Klaviyo
Segmentation runs deep — unlimited conditions across behaviour, purchase history and predictive scores such as churn risk and lifetime value, real-time segment updates, and more than 60 prebuilt flows across email, SMS and push on top of more than 150 email templates. What holds it back is the testing half of the story: we found no public information on A/B testing, send-time optimisation or holdout groups.
Mailchimp
A visual flow map with conditional and percentage splits, up to three segmentable triggers, a webhook step and flow stats is a genuine journey builder, with dynamic content and custom-coded templates gated by plan and events able to start journeys from the API. We found no public information on send-time optimisation, holdout groups, or campaign-level testing that reports significance, which is what separates this from the top band.
Deliverability infrastructure
Klaviyo
There is a published deliverability guide covering bounce types, spam traps and blacklists, and it documents a 30-day dedicated-IP warm-up plus the complaint-level maths mailbox providers apply. We found no public information on SPF, DKIM or DMARC setup, custom sending domains, automatic bounce suppression or complaint-loop handling, which is the documented baseline this buyer expects before anything else counts.
Mailchimp
Authentication is documented down to the DNS records — two CNAMEs for DKIM and one TXT for DMARC, with automated setup via Entri — and dedicated IPs come with a documented warm-up of roughly 30 days, custom reverse DNS and sender-domain checks; bounces are auto-categorised soft or hard with engagement factored into cleaning. We found no public information on complaint-loop handling, seed or inbox-placement testing, or reputation monitoring surfaced to the customer, and bounce reasons are kept only 30 days and, per the vendor's own documentation, cannot be exported as a full list.
Consent, proof & tracking limits
Klaviyo
Every form submission is automatically timestamped and version-labelled into a consent log, contacts can be segmented and suppressed by consent status, and built-in tools export or delete a person's data with a list of deleted profiles kept as proof. We found no public information on double opt-in being the documented default, on product-level unsubscribe handling, or on any way to switch open and click tracking off.
Mailchimp
Double opt-in exists per audience but is one of two offered methods rather than a default, and it can only be enabled on Mailchimp signup forms — API-created contacts sit outside it. The proof story is stronger than a bare timestamp: GDPR form wording is recorded in plain text and viewable on the contact profile, editing a checkbox invalidates prior consent, and SMS exports include consent source, time and revocation. We found no public information on turning open and click tracking off per campaign, pixel-free sending, unsubscribe honoured across audiences, or retention rules for inactive subscribers.
List ownership, import & exit
Klaviyo
Exit is half-documented: profiles can be exported and deleted individually, the processing agreement commits to deleting customer data within 90 days of termination with return on request, and APIs, webhooks and warehouse syncs are offered for syncing elsewhere. We found no public information on bulk import, full-fidelity export including engagement history, or any statement on export throttling.
Mailchimp
Exit is engineered rather than improvised: a whole-account export as a zip covering audiences, campaign and template content, contact events and granular reporting, per-contact CSV bundles with opens, clicks and campaign interactions, and API-driven export jobs, plus permanent-delete and forget actions per contact. The friction is explicit metering — one export at a time and one per 24-hour period, enforced with error responses — and contact-level data access exports must be run per audience; migration services are documented only for arriving Premium customers in their first 30 days, and we found no public information on outbound migration tooling.
Integrations & API
Klaviyo
The connection surface is broad — a native Shopify integration, more than 350 prebuilt integrations, APIs, webhooks, SDKs and warehouse syncs — but I cannot build on it with confidence: the API terms set rate limits "in our sole discretion", allow the APIs to be modified or unsupported "at any time without notice", and permit suspension of API access without notice. We found no public information on a sandbox, webhook retries or a deprecation policy.
Mailchimp
A versioned Marketing API at 3.0.91 with batch operations, list webhooks for core subscriber events, an events endpoint to trigger automations and a health check, next to a transactional API taking raw MIME, scheduling sends, managing subaccounts and documenting a rate limit of 20 calls per minute for message search; Shopify, Salesforce, Stripe and Square are named among 300+ apps with Salesforce described as two-way sync. Deprecation is practised with dates in public documentation — the legacy Export API was given a retirement date and Conversations endpoints were deprecated in favour of Inbox — but we found no public information on a sandbox, webhook retry behaviour, or general rate limits for the marketing API, which is exactly the documentation a builder needs before committing.
European sovereignty
Klaviyo
The contracting entity is Klaviyo, Inc. of Boston and the processing agreement permits storing customer data wherever Klaviyo or its subprocessors maintain facilities; we found no public information on EU hosting for any part of the chain, and the agreement even contemplates requests under FISA Section 702. Transfers rest on the EU-US Data Privacy Framework and standard contractual clauses under Irish law, which is precisely the Schrems II argument, and while a subprocessor list URL is referenced, we found no public information naming the subprocessors.
Mailchimp
Intuit Inc. is the US contracting entity, hosting is US by fixed default with no EU region offered in the captured pages, and a subprocessor list for the service is not published — names appear only incidentally, such as Google hosting export files and FullStory and Medallia for session replay. Transfers do carry a stated basis, with annual EU-US Data Privacy Framework certification and standard contractual clauses integrated into the data processing addendum as a fallback, which is the only reason this rises off the floor.
Pricing transparency
Klaviyo
The free tier is precisely public — "Bis zu 250 Profile", "500 E-Mails pro Monat", mobile messaging worth "5 $/Monat" — but the captured pricing pages state no figures for paid tiers, which are described only as scaling on contacts and channels with a custom enterprise quote. We found no public information on paid-tier prices, overage rates or VAT treatment; the only calculator offered is for ROI.
Mailchimp
Headline prices are public — Essentials from €11.50 per month and Standard with up to 6,000 emails a month in one capture, while earlier captures give €11.34 and €17.45 for the same plans — alongside per-plan send limits, flow points, seats, a free tier under 250 contacts, annual plans above 10,000 contacts, pay-as-you-go credits and a 15% nonprofit discount. A real invoice still cannot be computed from these pages: we found no public information on the overage rate, VAT treatment, a monthly price for the Premium tier, or a price calculator, the SMS add-on requires an application and approval without showing a price, Customer Success appears only in custom plans from USD 299 per month, and the captured pages describe both sending paused at the limit and overage fees applying.
Sovereignty, side by side
Dimension
Klaviyo
Mailchimp
Legal entity
Not determined
Not determined
Ownership
Not determined
Foreign-controlled
Data residency
Not determined
Not determined
Subprocessors
Not determined
Not determined
Facts, side by side
Only facts both products carry under the same definition — anything else would not be a fair row.