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 Skeptic
Has seen every vendor claim 99% deliverability and GDPR compliance on the same page. Reads for the contact-tier staircase, the overage rate, the feature that begins two tiers up, and whether "EU hosting" covers the sending infrastructure or only the database.
Klaviyo
Mailchimp
This judge's pick
Criterion by criterion
Campaigns & automation
Klaviyo
150+ email templates and 60+ prebuilt flows across email, SMS and push, with segmentation on attributes, behaviour and predictive values that updates in real time and unlimited lookback, is genuinely above the midpoint — but we found no public information on subject-line A/B testing, send-time optimisation or journey branching, so the top half of the ladder stays out of reach.
Mailchimp
The flow builder is the real thing — conditional and percentage splits, wait-for-trigger, webhooks and API-triggered entry, dynamic content from Standard up — but flow depth itself is metered by plan (200 flow points on Standard versus 4 steps per flow below). We found no public information on A/B testing, send-time optimisation or holdout groups.
Deliverability infrastructure
Klaviyo
There is real documentation here, not just a marketing number: a deliverability guide covering bounce types, spam traps, blacklists and sending infrastructure, a 30-day dedicated-IP warm-up, and the 1-complaint-per-1,000-messages threshold — but the captured pages show no SPF, DKIM or DMARC setup guidance, no custom sending domain and no stated hard-bounce suppression policy, so it sits at the lower rung with dedicated-IP documentation as the one bright spot.
Mailchimp
Authentication is documented down to the DNS records — two CNAMEs for DKIM, one TXT for DMARC, with an automated setup path — plus dedicated IPs with a roughly 30-day warm-up and automatic soft/hard bounce categorisation that factors engagement into cleaning. We found no public information on complaint-loop handling or seed and inbox-placement testing, and bounce reasons expire after 30 days with no bulk export.
Consent, proof & tracking limits
Klaviyo
Form submissions are automatically timestamped and version-labelled into a consent log, contacts can be segmented and suppressed by consent status with EU/UK geo-targeted forms, and per-person export and deletion tools exist — that is a serious consent record — but we found no public information on double opt-in as a documented default, on unsubscribe handling, or on any way to switch off open and click tracking, while analytics data is stated to be processed with generative AI and machine learning.
Mailchimp
Double opt-in exists per audience but only for Mailchimp signup forms — contacts added via API cannot get it — and single opt-in is offered equally, so it is a choice rather than a default. The versioned form wording retrievable on each contact's profile is genuinely proof-grade consent evidence; we found no public information on switching open and click tracking off, or on unsubscribe honoured across audiences.
List ownership, import & exit
Klaviyo
Individual profiles can be exported and deleted, a list of deleted profiles is kept as proof, and the data processing agreement commits to deleting remaining copies within 90 days of termination with return on request — but we found no public information on bulk export of engagement history, campaigns or templates, or on whether export is throttled, and the only documented return right is the contractual one.
Mailchimp
Exit is materially supported: an account export as a zip with audiences, campaign and template content, contact events and reporting, opens and clicks files per contact, and documented permanent deletion endpoints. What caps it is the metering — one export per 24 hours, per-audience exports for access requests, and files hosted by Google behind signed URLs that skip user verification.
Integrations & API
Klaviyo
350+ prebuilt integrations, a native Shopify relationship claimed as the preferred email platform partner, and a developer surface of APIs, webhooks, SDKs and warehouse syncs clear the middle anchor — but the API terms reserve the right to modify or terminate API access without notice and set rate limits in Klaviyo's sole discretion, and we found no public information on documented rate limits, a sandbox, or webhook retries.
Mailchimp
Named integrations for the shops and CRMs that matter — Shopify, Square, Lightspeed, a two-way Salesforce sync — across 300+ apps, with marketing and transactional APIs, webhooks in both directions and batch operations. We found no public information on a sandbox or webhook retries, and rate limits appear only for a single search method at 20 calls per minute.
European sovereignty
Klaviyo
The contracting entity is Klaviyo, Inc. of Boston, and the data processing agreement permits storage and processing anywhere Klaviyo or its subprocessors maintain facilities with no region lock, resting transfers on the EU-U.S. Data Privacy Framework and standard contractual clauses — every send is a Schrems II argument, with FISA 702 and Executive Order 12333 requests expressly contemplated; a published subprocessor list address and a stated transfer basis are the only things lifting this off the floor.
Mailchimp
US contracting entity under Intuit, US hosting with no EU option anywhere on the captured pages, and no published subprocessor list — names like Twilio, FullStory, Medallia and Google appear only incidentally in the privacy statement. Transfers do carry a stated basis (annual DPF certification with SCCs as contractual fallback), which is more than nothing, but the entire structure rests on the framework this buyer does not trust, and this category weighs it heavily.
Pricing transparency
Klaviyo
The free tier is exact and public — up to 250 active profiles, 500 emails per month, mobile messaging worth 5 $/Monat and 10,000 Composer credits — but the captured pricing pages state no paid prices at all, only that subscriptions scale with the number of contacts and channels used, enterprise is a custom quote, and there are no overage rates and no statement of VAT treatment; a buyer cannot compute a paid invoice from these pages.
Mailchimp
Headline monthly prices and per-tier send limits are public — Standard with 6,000 emails per month, the captured pages giving different figures for Essentials (€11.34 versus €11.50 per month) and Standard (€17.45 versus €17.68 per month) — with feature gating laid out per tier. Overage rates, VAT treatment and the price of the SMS add-on, dedicated IPs and high-volume plans are not stated, and the captured pages describe exceeding the limit both as incurring extra costs and as paused sending.
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.