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 Deliverability Engineer
Cares about one number nobody publishes honestly: what reaches the inbox. Reads for authentication, IP and domain reputation, bounce discipline and sunsetting. Ignores every advertised delivery rate on principle — the infrastructure either is documented or it is not.
Klaviyo
Mailchimp
This judge's pick
Criterion by criterion
Campaigns & automation
Klaviyo
Templates, a drag-and-drop editor, more than 60 prebuilt flows across email, SMS and push, and segmentation that is genuinely deep — real-time updates, unlimited conditions, behavioural and custom-property dimensions, ML-driven grouping — are all documented. We found no public information on A/B testing, branching journeys, dynamic content per segment or send-time optimisation, so I cannot credit the top of the range.
Mailchimp
Automation flows are documented as a visual journey map with conditional and percentage splits, wait steps, webhooks and up to three segmentable triggers, plus dynamic content on paid tiers and an API trigger that starts journeys from outside events. We found no public information on send-time optimisation, holdout groups, or A/B testing that reports significance, which keeps a genuinely strong journey builder short of the top band; flow depth is also tier-gated to four steps on the entry paid plan.
Deliverability infrastructure
Klaviyo
A public deliverability guide documents bounce types as seen in the product, spam traps, blacklists and list hygiene, dedicated IP warm-up is documented at 30 days, and the guidance that 1 complaint per 1,000 messages is where mailbox providers consider the complaint level elevated is honest, useful material. We found no public information on SPF, DKIM or DMARC setup documentation, inbox-placement or seed testing, or an engagement-based sunsetting policy, so the authentication spine is a topic heading rather than shown setup documentation.
Mailchimp
Authentication is documented properly — domain verification first, then two CNAME records for DKIM and one TXT for DMARC, with an automated setup method and guidance on the Gmail and Yahoo DMARC requirements — and bounces are categorised soft or hard from SMTP replies with subscriber engagement factored into cleaning decisions. Dedicated IPs are provisioned with a roughly 30-day warm-up and custom reverse DNS on the transactional side. We found no public information on inbox-placement or seed testing, complaint-loop handling, or sunsetting of inactive subscribers, so the top of this band stays out of reach.
Consent, proof & tracking limits
Klaviyo
Every form submission is automatically timestamped and version-labelled to form a consent log, consent forms can be geo-targeted to EU and UK visitors only, profiles without valid consent can be suppressed, and built-in tools export or delete a person's data with a deleted-profile list kept as proof of compliance. We found no public information on tracking that can be limited or switched off, on double opt-in as the documented default, or on unsubscribe handling honoured across lists.
Mailchimp
Double opt-in exists per audience with a customisable confirmation mail, the captured pages show a plain-text record of the GDPR form wording stored on each contact profile, and exports carry SMS consent source and revocation times — consent evidence a long way past a bare timestamp, with a forget endpoint and per-audience contact export behind it. But double opt-in is offered as one of two opt-in methods rather than a documented default and can be enabled only on Mailchimp signup forms, and we found no public information on switching open or click tracking off, pixel-free sending, or unsubscribe honoured across audiences.
List ownership, import & exit
Klaviyo
Individual records can be found, exported and deleted on demand, the contract commits Klaviyo to deleting all further copies within 90 days of termination, and a deletion log evidences that deletion requests were honoured. We found no public information on bulk export of subscribers with engagement history, campaigns or templates in open formats, or on import with attributes intact — the exit story is contract language, not a documented feature.
Mailchimp
Exit is documented as a real feature: a whole-account zip with audiences, campaign content, templates, gallery assets, contact events and reporting data, plus per-contact CSVs that include opens, clicks and campaign interactions, and API actions that delete all personally identifiable information or forget a contact. The captured pages also state only one export can be generated per 24 hours and that contact-level exports must be repeated per audience when a contact sits in several, and the migration services we can see run inbound only, for Premium customers or the first 30 days of an account.
Integrations & API
Klaviyo
More than 350 maintained integrations, a native Shopify partnership, and APIs, webhooks, SDKs and warehouse syncs are documented, which covers a real build surface. But rate limits are stated only as set and enforced at Klaviyo's sole discretion, we found no public information on webhook retries or a sandbox, and the terms reserve termination of API access at any time for any reason — that is a surface a sender builds on at the vendor's pleasure.
Mailchimp
Over 300 integrations included in every plan, named two-way sync with Salesforce and a Shopify connection, and two documented APIs — marketing (version 3.0.91, batch operations, list webhooks) and transactional (raw MIME sending, scheduled mail, SMS, subaccounts, inbound routes, tracking domains). Per-endpoint rate limits are stated and deprecation is practised openly, with the legacy export API given an end date; we found no public information on a sandbox or documented webhook retries.
European sovereignty
Klaviyo
The contracting entity is Klaviyo, Inc. of Boston, the data processing agreement permits storing and processing customer data wherever Klaviyo or its subprocessors maintain facilities, and transfers rest on the EU-US Data Privacy Framework and standard contractual clauses — a Schrems II argument every EU buyer must make, with the agreement even contemplating FISA 702 and Executive Order 12333 requests. We found no public information on an EU hosting option, and data residency and ownership are unconfirmed on the vendor's own captured pages; a subprocessor list is published at a Klaviyo URL.
Mailchimp
Sovereign this is not: the contracting entity is The Rocket Science Group LLC under Intuit Inc. in Mountain View, US storage is the fixed default with no EU hosting option on any captured page, and even export files are hosted by Google. Transfers do carry a stated basis — annual EU-US Data Privacy Framework certification with SCCs folded into the data processing addendum as fallback — and some processors are named, but we found no public information confirming a complete subprocessor list, and session replay runs through FullStory and Medallia.
Pricing transparency
Klaviyo
The free tier is fully quantified publicly — up to 250 active profiles, 500 emails per month, mobile messaging worth 5 $ per month and Composer usage worth 5 € per month — and paid tiers are stated to carry no send or profile limits after upgrading. But the captured pricing page states no paid prices at all: paid subscriptions are described only as scaling by contact count and channels with enterprise on custom quote, and we found no public information on overage rates, VAT treatment, or what a given list size would actually pay.
Mailchimp
Monthly prices are public with send limits per plan, automation flow depth per tier, and feature boundaries down to audiences, seats and onboarding sessions — enough to price the shape of a plan before talking to anyone. But overage is only ever stated as extra costs applying when limits are exceeded, we found no public information on VAT treatment or a Premium price figure, and the captured pages give different figures for the same plans — Standard at €17.45/Monat and at €17.68/Monat, Essentials at €11.34/Monat and at €11.50/Monat — which we do not choose between.
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.