Whenever brand owners experience rapid growth in their customer base and product demand, they must contend with many new challenges in maintaining control over their core processes that support them. For instance, email lists tend to grow exponentially as brands grow in revenue.
When starting out as a small-to-medium-sized e-commerce brand that sells direct to consumers, brands’ marketing teams focus on creating visually appealing templates and interfaces that encourage visitors to sign up for email subscriptions.
When these companies scale into the enterprise level, they have different needs than what has already been created. High-volume e-commerce brands do not care if you have a large selection of aesthetically pleasing templates; rather, they care how many emails they can send through your API at once, how many batches of emails they can send at the same time, and whether or not they have a reliable deliverability service level agreement (SLA).
They also care about how quickly their transactional purchase receipt will be delivered during a spike in Black Friday traffic.
The e-commerce email space is flooded with vendors that have consumer-grade product offerings but claim to have enterprise capability. The problem with these companies and their claims is that they do not have real-time data to back them up.
Specifically, companies that generate $200,000/month in e-commerce revenue will often experience a sudden stop in the number of emails that they can deliver within the timeframe of a sales spike (often referred to as a "blackout"). Typically, the reason for this sudden drop is not due to the subject line of the emails being sent by the company, but is rather due to the infrastructure supporting the e-commerce emails.
The purpose of finding the right email marketing saas software is to eliminate the marketing hype associated with these vendors’ claims and have an objective look at the technical capabilities that each vendor offers and how they are able to support the world's largest digital storefronts.
High-Volume E-commerce Emails
The e-commerce email landscape is separated into several distinct categories. As of the writing of this article, there is industry consensus that Klaviyo is the dominant player in terms of revenue attribution, native Shopify integrations, and the availability of robust reporting tools that allow you to analyze the performance of your email marketing efforts.
However, when e-commerce brands begin to grow quickly, brands that were initially locked into a subscription list-based pricing model will suffer severe penalties with regard to their pricing due to the scalability of their business.
Deciding what email platform to use for eCommerce when the number of email messages exceeds millions has become more complicated for enterprise decision makers, as they are now primarily choosing email platforms based on their infrastructure's ability to handle significantly increased volumes of messaging.
The high-volume space is dominated by companies such as Maropost and Braze because they provide dedicated IP addresses, high API concurrency limits, and cross-brand identity stitching.
At the same time, there is also a pricing revolution taking place. Cost-conscious marketers are using Omnisend and Brevo to execute omnichannel marketing campaigns, which bundle email and SMS together, without having to pay the premium prices charged by the top companies.
To evaluate the best high-volume email platforms, eCommerce marketers need to stop using generic feature lists. Instead, they must take a forensic approach to evaluating each platform's true cost-per-email thresholds, data model compatibility, and the harsh realities of migrating a company's historical Email Attribution Data without causing interruptions to Automated Revenue Loops.
When evaluating email marketing saas software for eCommerce, the metrics for evaluation drastically change when moving upmarket. What works for a small lean company will cripple a mature larger company.
High-Volume Throughput and High-API Concurrency
Sending high volumes of email messages requires a tremendous amount of data to be processed in real-time.
For example, if an eCommerce site generates 10,000 abandoned cart events in one hour due to a holiday sale, all of those cart abandonment events need to be processed by the email platform at that precise time. If the API rate limits are low, that will block the email from going out until the queue is cleared, which means any cart abandonment emails sent after the delay will not have a chance of being converted into actual sales.
All of the leading email platforms have published their batch send concurrency limits. If an email vendor will not disclose their API rate limits during the sales process, that is an indication that their API rate limit is going to be a liability.
Deliverability Infrastructure
Shared IP addresses will not work for high-volume email senders. A single rogue sender on a shared IP address can destroy the deliverability rates for all of the brands using that shared IP address.
Dedicated IP addresses and, most importantly, support for the warm-up of dedicated IPs, are provided by the enterprise platforms. It is not enough to flip a switch and blast a million emails from the newly established IP.
The warm-up of a new IP address, referred to as the "throttled sequence," is critical to building a good reputation with large inbox providers.
Pricing Architecture Breakpoints
Your operating margins are directly determined by the platform's pricing model. Most of the time, a platform's pricing model is based on the number of active contacts on your list.
This model penalizes brands with large and old databases, as it is much less expensive to use volume-based pricing as send volume increases. It is a requirement for every CMO to identify the pricing breakpoint at which the list-based model becomes economically unsustainable.
The Heavyweight E-commerce Platform Dossier
To identify the companies with the most effective capabilities within the high-volume e-commerce market, we must take a closer look at what they actually do versus their marketing claims. We will evaluate their raw technical infrastructure over their marketing hype.
1. Klaviyo
Klaviyo is the leading name in the direct-to-consumer market. Its primary advantage is a near-perfect integration with Shopify for data. Klaviyo operates as more of a customer data platform than an email vendor. The revenue attribution is super accurate right from the start.
In order to grow on Klaviyo, however, one must have a lot of funds available. The pricing model, based on the number of active subscribers, is very steep—so it puts a huge strain on those companies that have high levels of growth, acquire lots of subscribers, and experience low conversion rates.
Therefore, those that send a lot of emails through Klaviyo frequently reach a limit, at which point they are weighing the value of the platform's productivity and analytics against the sky-high invoices.
2. Maropost
Maropost is a high-volume, cloud-based architectural model designed specifically for enterprise-quality throughput. When a multi-million dollar business requires ironclad Deliverability Service Level Agreements (SLAs), Maropost usually makes the shortlist.
Maropost offers dedicated IPs, extensive deliverability monitoring, and much of the backend server resources necessary to send millions of Transactional and Promotional emails with zero latency.
The downside is that you will experience a more difficult learning curve due to its interface being designed for database operators and more advanced online marketers rather than beginners. Enterprise contract minimums are typically private; therefore, exact throughput caps must be negotiated directly with the Maropost sales team.
3. Braze
Braze is an all-in-one, multi-channel, multi-layered orchestration engine. It is preferred among the very complex multi-brand enterprises that must connect customer identities through their mobile applications, websites, and separate CRM databases.
While the traditional platforms only focused on the inbox, Braze utilizes their ability to activate data through Push Notifications, In-App Messaging, and Email simultaneously. Braze has an elite level of data ingestion capabilities; they can handle excessive API loads without any delay.
It is a highly technical implementation to onboard Braze. A very strong base of engineering knowledge and support is necessary to map out the necessary data models, thus being overkill for an average single-product storefront, but an absolute requirement for a massive retail conglomerate.
4. Omnisend
Omnisend has successfully claimed a large segment of the overall market, offering a more aggressive omnichannel solution than Klaviyo. They combine both Email and SMS Automation Workflows into a single Automation Tree to eliminate silos of disconnected data, which has been a problem for Mid-Market Brands.
Omnisend is the go-to for eCommerce businesses who are trying to reduce their costs while preserving the revenue-generating power of automation. They do an excellent job with high-volume eCommerce, especially impacting the Shopify and WooCommerce platforms.
The major difference between them and Braze is that they do not have the level of enterprise identity stitching that Braze possesses. But from a cost-to-performance perspective, Omnisend is extremely attractive to brands whose business model is to scale their direct-to-consumer (DTC) operations.
5. Brevo
Brevo is a transactional champion. Formerly known as Sendinblue, Brevo has an entirely different pricing structure than most other email service providers and is based on messaging rather than contacts.
When you have a massive list of subscribers, but you don't send a lot of messages per month, using Brevo can produce immediate and massive cost savings. Brevo offers an SMTP infrastructure that has been tested in battle.
When you have a high volume of transactional emails, such as hundreds or even thousands of order confirmations, shipping notifications, and automated receipts, Brevo has the ability to infinitely expand and process that volume of transactions effortlessly. Their system also has an easy-to-use visual automation builder, but it does not have the same granularity for building out niche eCommerce lifecycle flows like Klaviyo. But, you can count on the sending infrastructure to be virtually "bulletproof."
6. ActiveCampaign
When you think of ActiveCampaign, you think of complex automation logic. Most people associate ActiveCampaign mainly with B2B lead nurturing, but they also have a very sophisticated eCommerce automation capability.
They have the unique feature of branching logic that allows brands to build out hyper-specific customer lifecycle journeys based on behavioral triggers that are extremely granular. When you are processing high volume, ActiveCampaign does a great job of handling data well.
The only downside to using ActiveCampaign during flash sales is that there may be minor latency when ingesting massive amounts of data compared to enterprise-level transactional systems. ActiveCampaign is better suited for brands who compete based on highly personalized and behavior-driven follow-ups rather than just sheer volume of broadcast messages.
7. Mailchimp
Mailchimp has been an email marketing service provider since email marketing began and will always be one of the "legacy" giants. The vast majority of the major brands have likely used Mailchimp at least once during the evolution of email marketing.
The Mailchimp user experience interface is simple for anyone to use and they don't take long to set up. However, as a company grows, they may find Mailchimp doesn't work as well for them, suffering from a limited data structure and revenue attribution tracking.
The reporting system for Mailchimp will likely break down when trying to find which automated flow brought in a particular multi-item purchase when the customer came from a custom-built headless storefront. Mailchimp is a great place to start but usually is not the end product for larger companies.
8. Drip
Drip has a heavy emphasis on creating visual stories and workflows for e-commerce. With Drip's visual builder, marketing teams can create elaborate automated workflows without having to use any code at all. The platform integrates seamlessly with most of the major storefront platforms and provides excellent tracking of user behavior.
The limitations of Drip typically occur when businesses reach true enterprise level. Businesses that have extremely high processing demands and sophisticated stitching of multi-brand data will frequently hit the wall when attempting to utilize Drip.
For businesses in the aggressive mid-market space, Drip is a powerful option; however, businesses will need to evaluate their sending volume carefully. The nature of the product is advantageous for its target market; however, as the number of transactions increases, the need for dedicated hardware infrastructure increases as well.
9. MailerLite
MailerLite offers an incredibly clean user experience and aggressive pricing for early-stage and mid-market growth. Their editor is fast, their deliverability is consistently reliable for standard use cases, and their customer support is highly rated.
However, they do not position themselves as an enterprise powerhouse. You will not find aggressive deliverability SLAs or dedicated enterprise throughput guarantees engineered for the top 1% of retail senders. It is an exceptionally good tool for its target demographic, but high-volume operators will eventually require infrastructure built specifically for heavy payload delivery.
The SMS-First Dilemma: It is critical to understand that there is a huge gap between Core Email Infrastructure and SMS-First Platforms like Attentive and Yotpo. These companies have established dominance in the SMS messaging space. However, when Core Email is routed through these platforms, it often creates disconnected silos of data. An operator sending high volumes of SMS must separate their specified SMS layer from their core Email Infrastructure.
The Matrix: Matching Send Volume, Vendor Capability & Infrastructure
Selecting a vendor is about how well you align your business's operational bottlenecks with the platform's capabilities. A vendor that has a generic approach to your situation could easily mismatch your technology stack. Here are three examples of real-world deployments:
Scenario A: The Transactional Powerhouse
A company that sends 3 million emails per month mainly for order confirmations, shipping updates, and transaction receipts. Waiting for email to reach customers? That's not going to work.
The Suggested Action: Use Brevo or Maropost. Utilize their enhanced SMTP routing and variable-based pricing. This type of pricing perfectly aligns with high-volume, low-latency requirements.
Scenario B: The Omnichannel Business Owner
A DTC business that has been growing rapidly and has recently hit a wall with pricing from its legacy platform. It requires deep integration with Shopify, yet wants to consolidate its Email and SMS spend into one monthly invoice.
The Suggested Action: Omnisend is the right solution because it effectively and affordably combines all channels, generating predictable revenue via Abandoned Cart and Welcome Series automation while providing additional data points from other platforms.
Scenario C: The Multi-Brand Company
An enterprise customer with multiple entities operating as sub-brands, responsible for managing all of them. As a multi-brand operator, the ideal situation is to create a single cross-entity customer profile using the data generated by a customized mobile application and a headless digital storefront so that each sub-brand can leverage each other's data, allowing the creation of one comprehensive marketing strategy.
The Suggested Action: Move to Braze. The heavy lifting in terms of engineering is immense. However, this is the only architecture that can effectively manage large disparate levels of data ingestion without failure.
High-Volume Migration Playbook
Migrating a database containing two million active subscribers can be risky if not done correctly. The ramifications of migrating incorrectly would be spam trap activations, terminated domain reputation, and the loss of revenue attribution connections.
In order to have a successful transition, it is crucial to strictly follow an operational playbook.
Phase 1: Data Model Mapping
Data modeling needs to be established prior to exporting any CSV files, so know how the current vendor defines the term 'purchase' as opposed to how the new vendor defines it (they may not match). If you do not map out custom fields, all previous revenue attribution will cease to exist on the day you change over to the new vendor.
Phase 2: Warm-Up Sequence
You will not be able to send two million emails from the dedicated IP address on day one. Inbox providers like Gmail and Yahoo will automatically flag the incoming volume as a botnet attack and consequently blackhole the domain.
Therefore, you will need to create segmentation lists of your most engaged users. These are users who clicked on an email within the past 14 days. From there, you will need to gradually push traffic from your total daily volume through the new dedicated IP. The warm-up period can range between 30 to 45 days, depending on the strategy used to scale the volume.
Phase 3: Suppression List Porting
Do not leave any unsubscribed users behind. It is required both legally and operationally to port your hard bounces and suppression lists over to your new vendor. Hitting a spam trap from a newly warmed IP may delay the migration process by months.
Conclusion
While the barriers to entry for marketing technology have all but disappeared, the barrier to scaling has significantly increased. E-commerce platforms that dominate will not win by providing the best templates, but by providing better server architecture.
If your revenue is tied directly to your ability to send a message to the inbox within 3 seconds, there is no room for error in your infrastructure. Make sure to ask vendors the API rate limits they are willing to provide, request transparency on the level of service agreement (SLA) for deliverability, and model your operational cost over the next 24-month period. This should help in choosing the software that fixes the most difficult technical bottleneck you currently face on a daily basis.
Q&A About The Best Email Marketing SaaS Software
How do batch send concurrency limits reduce the velocity of revenue during flash sales?
When a high-volume brand has a site-wide flash sale, the event causes an influx of tens of thousands of automated behaviors and events like viewed products, abandoned carts, and instant purchases. If the marketing software has low API concurrency, it will not be able to ingest the volume of data simultaneously; therefore, the events go into a queue causing a time delay in operations.
If an abandoned cart email is supposed to be sent 30 minutes after an abandonment, it may not go out for up to six hours. By the time it gets to an inbox, the buyer’s intent has faded, which accordingly eliminates the velocity of expected revenue.
What is the actual financial impact of changing from list price to message volume pricing?
List pricing penalizes you for building your list, charging for every email address stored regardless of how often you are sending to that address. For brands with large databases with older addresses that have highly targeted send habits, this creates a significant monthly cost.
Moving to a message volume-based pricing model strengthens the opposite equation. You only pay for the payload you deliver. This allows you to maintain large quantities of suppression or re-engagement lists at no additional charge, allowing for a true reduction in per-mail costs, and allows operators to expand their margins.
Why does historical attribution break when migrating to an enterprise platform?
Attribution normally breaks down when migrating to another platform because the platforms use vendor-specific logic to tie a click on an email back to a store checkout event. When migrating, it is common to export a static list without also migrating the associated event timeline data (referred to as metadata).
When a new platform does not have a data structure that explicitly maps to the historical format of the legacy platform, the new system loses all reference to that historical data of how users produced revenue in the past, thus resetting the lifetime value (LTV) models to zero.
