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 Data Protection Officer
Signs off the tool that holds named people and records what each of them opened. Wants double opt-in with a proof that survives a complaint, tracking that can be switched off, and an answer to where the behavioural data lives that does not require a Schrems II argument.
Klaviyo
Mailchimp
This judge's pick
Criterion by criterion
Campaigns & automation
Klaviyo
Segmentation is the documented strength: real-time segments on demographics, browsing behaviour, purchase history and custom properties with unlimited conditions, plus predictive and AI-generated segments, alongside 60+ prebuilt flows and 150+ email templates on a drag-and-drop editor. We found no public information on A/B testing with significance reporting, journey branching on behaviour and data, or send-time optimisation, so this sits above basic list-and-welcome tooling but well short of a fully evidenced journey platform.
Mailchimp
The captured help pages show a visual journey builder with conditional and percentage splits, wait and trigger steps, entry filtered by segmenting conditions, and an API trigger so another system can start a journey; dynamic content and branded templates appear from the Standard tier upward. We found no public information on A/B testing, holdout groups or send-time optimisation, which is what keeps this short of the top band.
Deliverability infrastructure
Klaviyo
There is a real public deliverability guide covering bounce types and where they are found in the product, spam traps and blacklists, sending infrastructure and the pros and cons of double opt-in, plus guidance that one complaint per 1,000 messages is where mailbox providers consider a sender elevated and a documented 30-day dedicated-IP warm-up. We found no public information on SPF, DKIM or DMARC setup documentation, automatic hard-bounce suppression, or complaint-loop handling, which is what would raise this further.
Mailchimp
Authentication is properly documented — domain verification, two CNAME records for DKIM and a TXT record for DMARC, with automated setup and the Gmail and Yahoo requirement spelled out — and bounces are categorised from SMTP replies with subscriber engagement factored into cleaning, plus dedicated IPs with a roughly 30-day warm-up. We found no public information on complaint-loop handling, seed or inbox-placement testing, or published list-hygiene guidance, so it sits between the middle and upper bands.
Consent, proof & tracking limits
Klaviyo
But we found no public information on double opt-in being offered as a documented default (the deliverability guide only weighs its pros and cons), on open and click tracking being limitable or switchable off, on pixel-free sending, or on preference-centre granularity and retention rules for inactive subscribers.
Mailchimp
Double opt-in exists with a customisable confirmation email, and the GDPR fields each contact saw are recorded in plain text and viewable on their profile — genuinely usable proof when a complaint lands. But double opt-in must be enabled per audience rather than being the default, and we found no public information on switching open or click tracking off per campaign, on an unsubscribe honoured across lists, or on retention rules for inactive subscribers.
List ownership, import & exit
Klaviyo
Exit hygiene is contractually documented: all customer personal data is deleted within 90 days of termination with return on request, individual profiles can be found, exported or deleted from the unified profile store, and the deletion log doubles as evidence of compliance. We found no public information on bulk export of the full list with custom attributes, engagement history or unsubscribe state, on campaigns and templates leaving in open formats, or on migration tooling in either direction — the parts that keep the list portable while the sender is still a customer.
Mailchimp
The account export is full-fidelity — audiences, campaign and template content, contact events and reporting data in one zip, with per-contact activity files covering opens and clicks — and permanent deletion and a forget action are both documented. Against that, exports are throttled to one per 24-hour period and can take minutes to days to build, bounce reasons cannot be exported in bulk, and a contact in multiple audiences has to be exported from each audience individually.
Integrations & API
Klaviyo
The surface is broad: more than 350 prebuilt integrations, a native and maintained Shopify partnership claimed across 117,000+ shared customers, and developer tooling spanning APIs, webhooks, SDKs and warehouse syncs. It falls short of the top tier because rate limits are set and enforced at the vendor's sole discretion rather than documented, we found no public information on a sandbox or webhook retries, and the API terms reserve the right to modify or stop supporting the APIs at any time without notice.
Mailchimp
Over 300 integrations include a two-way Salesforce sync plus Shopify, Stripe, Square and Zapier, and there is a documented Marketing API at version 3.0 with batch operations, list webhooks and inbound events, alongside a separate transactional API with its own webhooks and stated per-method rate limits. Marketing and transactional sending sit on two APIs rather than one, and we found no public information on webhook retries or a sandbox.
European sovereignty
Klaviyo
The contracting entity is Klaviyo, Inc. of Boston under Massachusetts law, and the data processing agreement authorises storage and processing wherever Klaviyo or its subprocessors maintain facilities — worldwide, with no regional lock — so behavioural data on EU subscribers is processed in the United States. Transfers rest on the Data Privacy Framework certification and standard contractual clauses with Irish governing law, transfer impact assessment support, a stated willingness to challenge FISA 702 and Executive Order 12333 requests, and a referenced published subprocessor list; that is the complete US-vendor transfer package, and it still requires a Schrems II argument to survive — we found no public information on any EU hosting or residency option.
Mailchimp
The contracting entity is US-based (The Rocket Science Group under Intuit), US hosting is the fixed default with no EU option offered anywhere in the captured pages, and the entire transfer story rests on Data Privacy Framework certification with standard contractual clauses as fallback — exactly the argument I would have to make rather than avoid. No subprocessor list is published on the vendor's own pages; the privacy statement names FullStory, Medallia and generative-AI providers touching the data, and export files are themselves hosted by Google.
Pricing transparency
Klaviyo
The free tier is fully computable — up to 250 active profiles, 500 emails per month, mobile messaging worth 5 $ per month and 10,000 Composer credits — but the paid tiers are described only as scaling on contact count and channels used, with enterprise on custom quote. We found no public information on any paid price figure, overage rate, feature boundary or VAT treatment, so a buyer cannot compute an invoice for a real list size from the captured pages.
Mailchimp
Monthly from-prices are public per tier with send limits stated (Standard up to 6,000 emails, Premium 150,000), feature tables show where flows, audiences and seats begin, and annual plans, pay-as-you-go and a free tier under 250 contacts are documented. Overage is announced but its rate is not stated, SMS credits and high-volume plans above 200,000 contacts are price-on-request, no VAT treatment is given, and the captured pages give different figures for the same tier — Essentials from €11.34 and from €11.50, Standard from €17.45 and from €17.68.
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.