Email Marketing Platforms · Mailchimp, Klaviyo & Campaign Monitor

Mailchimp (founded 2001, acquired by Intuit in 2021 for $12 billion) is the most widely recognised ESP globally — primarily because of its long-standing free tier that made it the default starting point for small businesses. Mailchimp has evolved from a simple newsletter tool into a broader marketing platform with automations, landing pages, CRM features, and advertising integrations.

Mailchimp strengths

• Ease of use. Mailchimp's interface is among the most user-friendly of any ESP — drag-and-drop email builder, simple automation workflow builder, and a clear navigation structure make it accessible without significant training.
• Starting point free tier. Mailchimp's free tier (up to 500 contacts, 1,000 sends/month) makes it a common first ESP for startups and small businesses. The migration away from Mailchimp as businesses scale is also very common — the free tier limitations encourage moving platforms as email marketing matures.
• Integrations. Mailchimp integrates with hundreds of platforms — Shopify, WooCommerce, Squarespace, Wix, and most major business software.

Mailchimp limitations

• E-commerce automation depth. Mailchimp's e-commerce automations (abandoned cart, product retargeting) are functional but less sophisticated than Klaviyo's — particularly for complex conditional logic and deep product data integration.
• Pricing at scale. Mailchimp charges per contact, and pricing increases rapidly as lists grow — often becoming more expensive than alternatives for large lists.

Klaviyo (founded 2012, IPO September 2023) has become the dominant ESP for direct-to-consumer (DTC) and e-commerce brands — particularly Shopify merchants. Klaviyo's native deep integration with Shopify (syncing customer purchase history, product data, and browsing behaviour in real time) enables automations and segmentation based on granular e-commerce data that ESPs with lighter integrations cannot match.

Klaviyo strengths

• E-commerce data integration. Klaviyo's Shopify integration syncs every customer event — page views, product views, cart additions, purchases, refunds — in real time. This enables automations like "send a win-back email to customers who purchased product X more than 90 days ago and have not returned" with product-specific dynamic content.
• Segmentation depth. Klaviyo's segmentation builder allows combining any combination of event data, profile properties, and engagement metrics — creating highly specific audience segments for targeted campaigns.
• Revenue attribution. Klaviyo attributes revenue to email sends, showing which campaigns and automations generate measurable purchase revenue — enabling ROI measurement for the email programme.
• SMS integration. Klaviyo's SMS marketing is integrated with the email platform — enabling coordinated email and SMS sequences within the same automation builder.

Klaviyo limitations

• Cost. Klaviyo's pricing (contact-based, SMS adds cost) is higher than Mailchimp at equivalent list sizes. The ROI from better targeting and automation typically justifies the cost for active e-commerce programmes, but it represents a significant budget commitment.

Campaign Monitor (founded 2004, now part of CM Group) is designed primarily for marketing agencies and enterprise brands that prioritise email design quality and client management capabilities. Its email builder produces visually polished emails with high design fidelity — making it a favourite for brands where visual design is a primary brand expression.

Campaign Monitor's unique feature for agencies is its multi-client management — allowing agencies to manage multiple client accounts from a single login with separate billing per client. Its deliverability infrastructure is consistently well-regarded. It lacks the deep e-commerce automation capabilities of Klaviyo and the broad integration ecosystem of Mailchimp.

HubSpot's email marketing is not a standalone product — it is one component of HubSpot's CRM and marketing automation platform. The email tool is tightly integrated with HubSpot CRM's contact and deal data, enabling email sends based on CRM lifecycle stage, deal stage, and contact properties that go beyond the e-commerce data that Klaviyo optimises for.

HubSpot email is the right choice for B2B businesses already using HubSpot CRM — the integration between sales pipeline, contact management, and email is seamless and provides the most complete view of the full customer journey from first email to closed deal. For businesses not using HubSpot CRM, the email product in isolation is expensive relative to standalone ESPs with equivalent capabilities.

ActiveCampaign is the platform most often recommended for businesses requiring sophisticated automation logic — conditional branching, goal-based automation management, lead scoring, and CRM integration for B2B lead nurturing. Its automation builder is among the most powerful available, enabling complex multi-step conditional workflows that less sophisticated platforms cannot replicate.

ActiveCampaign's segmentation, CRM integration, and automation depth make it well-suited for service businesses, SaaS companies, and B2B organisations with complex lead nurturing requirements. Its e-commerce integrations (Shopify, WooCommerce) are functional but not as deep as Klaviyo's.

Email deliverability — the proportion of sent emails that reach the recipient's inbox rather than spam folder — is a function of both the sender's practices and the ESP's infrastructure. All major ESPs provide shared or dedicated sending infrastructure with SPF, DKIM, and DMARC authentication support. February 2024 saw Google and Yahoo both begin enforcing stricter sender requirements — any sender sending more than 5,000 emails per day to Gmail addresses must have DMARC authentication configured. All major ESPs provide documentation and tools to help senders comply with these requirements.

All major ESPs integrate natively with Shopify, WooCommerce, and most major e-commerce platforms. The quality and depth of these integrations vary significantly: Klaviyo's Shopify integration syncs granular product and event data; Mailchimp's Shopify integration provides purchase data but less behavioural event detail. For non-e-commerce integrations (CRM, webinar platforms, lead generation tools), all major ESPs provide a Zapier integration that enables connection to hundreds of platforms not natively supported.

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