8 Best Mailgun Optimize Alternatives — 2026

Mailgun Optimize provides comprehensive email deliverability tools for developers and technical teams, but e-commerce brands—particularly those using Klaviyo—often need solutions focused on moving promotional emails from Gmail's Promotions tab to the Primary inbox. From specialized inbox placement platforms like Mailmend to all-in-one email marketing solutions, these eight alternatives offer different approaches to solving deliverability challenges based on your business model, technical resources, and growth objectives.

Key Takeaways

• E-commerce brands using Klaviyo need specialized solutions: Mailgun Optimize focuses on transactional email and developer tools, while platforms like Mailmend target promotional email placement in Gmail's Primary inbox—choose based on your primary email type

• Technical complexity varies dramatically: Mailgun Optimize requires API configuration and developer resources, while drag-and-drop solutions like Mailmend complete setup in under 5 minutes without code changes

• Transactional vs. promotional email needs differ: Postmark delivers 99%+ inbox placement for transactional emails but doesn't support marketing campaigns, making platform selection dependent on your email mix

• Built-in ESP tools reduce costs: Klaviyo's native Deliverability Hub comes included with existing subscriptions, providing basic monitoring without additional vendor relationships

• Time-to-results separates solutions: Traditional deliverability platforms require 1-2 weeks for IP warmup, while algorithmic inbox placement solutions claim results within 24 hours—critical for urgent campaigns like Black Friday

1. Mailmend — Gmail Primary Inbox Placement for Klaviyo E-commerce

Mailmend stands as the only deliverability solution purpose-built for moving e-commerce promotional emails from Gmail's Promotions tab to the Primary inbox without requiring content changes, technical configuration, or copywriting adjustments.

Key Features:

• Proprietary algorithmic inbox placement technology targeting Gmail's Primary tab

• Native drag-and-drop Klaviyo integration completing in under 5 minutes

• Pre-send test inbox analysis determining current placement before campaigns launch

• Built-in A/B testing through Klaviyo's native campaign framework

• Revenue attribution visible directly in Klaviyo analytics

• 1-to-1 dedicated client representatives included at all service levels

• Revenue satisfaction guarantee backing business outcomes

Pricing:

• Custom pricing based on send volume and projected revenue impact

• White-glove setup included without additional fees

• No minimum annual commitments disclosed

The platform's greatest strength lies in its singular focus on a problem other deliverability tools don't address. According to documented case studies, e-commerce brands using Mailmend report substantial performance improvements.

Dr. Squatch achieved 112% email revenue increase within 24 hours of implementation—the kind of immediate impact that traditional deliverability tools requiring weeks of warmup cannot match.

For Klaviyo users seeking to optimize promotional email revenue without overhauling their existing workflows, Mailmend provides a specialized approach that complements rather than replaces current email infrastructure. The platform works by embedding custom code into Klaviyo templates that counteracts Gmail's promotional categorization signals.

2. SendGrid — All-in-One Marketing and Transactional Platform

SendGrid has evolved into one of the most widely adopted email platforms, combining marketing campaign capabilities with transactional email infrastructure in a single solution.

Core Capabilities:

• Combined marketing and transactional email sending from unified platform

• SMTP relay and RESTful API integration options

• Email validation and list management tools (higher tiers)

• Dedicated IP options for sender reputation control

• Built-in analytics tracking opens, clicks, and bounces

• Extensive third-party integrations across CRM and marketing tools

2025 Pricing:

• Free: 100 emails/day

• Essentials: $19.95/month (50,000+ emails)

• Pro: $89.95/month (100,000+ emails)

• Premier: Custom pricing for high volumes

SendGrid excels as a mature platform with broad adoption and extensive integrations, making it suitable for organizations needing both transactional notifications and marketing campaigns under one roof. The platform handles everything from password resets to promotional newsletters without requiring separate vendor relationships.

However, SendGrid's pricing escalates significantly as email volume grows, and advanced features like email validation remain locked to expensive tiers. For e-commerce brands specifically seeking Gmail Primary tab placement, SendGrid's general-purpose approach doesn't target this use case—making it better suited for organizations prioritizing platform consolidation over inbox placement optimization.

Use Cases for SendGrid in E-commerce

SendGrid fits best when your business needs:

• Combined transactional and marketing email in one platform

• Extensive integration ecosystem for existing tech stack

• Self-service implementation with developer resources available

• Predictable pricing for moderate email volumes

3. Postmark — Premium Transactional Email Deliverability

Postmark focuses exclusively on transactional email, achieving 99%+ inbox placement by refusing to send marketing messages and maintaining strict sender reputation standards.

Transactional Strengths:

• Industry-leading deliverability rates for transactional messages

• Fast delivery times optimized for time-sensitive notifications

• Detailed delivery analytics and bounce tracking

• Simple API integration for developers

• Transparent per-volume pricing without hidden tiers

• Email/chat/phone support included at all levels

Transparent Pricing:

• Basic starts at $15/month

• Pro starts at $16.50/month

• Platform starts at $18.00/month

• Volume pricing scales predictably

• No marketing features or promotional email support

Postmark's deliberate limitation—transactional only—creates its advantage. By excluding marketing emails, the platform maintains exceptional sender reputation that ensures order confirmations, password resets, and receipts reach inboxes reliably.

For e-commerce brands, Postmark handles critical operational emails while dedicated marketing platforms manage promotional campaigns. This separation prevents promotional sending practices from affecting transactional deliverability—a common problem when both email types share infrastructure.

When Postmark Fits:

• Order confirmation and shipping notification emails

• Password reset and account verification messages

• Receipt and invoice delivery

• Any time-sensitive transactional communication

Postmark explicitly doesn't compete with promotional email optimization tools. Brands using Postmark for transactional email often pair it with Klaviyo for marketing and Mailmend for Primary tab placement—a stack addressing different deliverability challenges with specialized solutions.

4. Mailtrap — Email Testing and QA Before Production

Mailtrap occupies a different category than sending platforms, focusing on email testing and quality assurance during development rather than production delivery.

Testing Capabilities:

• Sandbox email environment preventing test emails from reaching real recipients

• Spam testing and deliverability scoring before campaigns launch

• HTML/CSS email preview across devices and clients

• Team collaboration features for approval workflows

• API access for automated testing integration

• Staging environment for safe experimentation

Pricing Structure:

• Free tier for basic testing needs

• Basic plan at $15/month

• Business plan at $85/month

• Enterprise at $750/month

Mailtrap solves a specific problem: catching deliverability issues before they affect real campaigns. Development teams use Mailtrap to test email functionality without accidentally sending messages to customers, while QA processes leverage spam testing to identify potential inbox placement problems.

For e-commerce brands, Mailtrap serves as a pre-production safety net rather than a Mailgun Optimize replacement. The platform helps identify why emails might land in spam folders but doesn't actively optimize placement for production sends.

Best Applications:

• Development environment email capture

• Pre-launch spam score testing

• Email template QA across clients

• Staging environment for marketing automation

5. SMTP2Go — SMTP Relay with Deliverability Monitoring

SMTP2Go provides dedicated SMTP relay services with built-in deliverability monitoring, offering more control over email infrastructure than shared sending platforms.

Infrastructure Features:

• Dedicated SMTP servers with configurable routing

• IP address management and dedicated IP options

• Real-time deliverability monitoring and alerting

• Email logging and search capabilities

• Security features including encryption and authentication

• Global server network for optimized delivery speeds

Pricing:

SMTP2GO offers volume-based plans:

• Free: 1,000 emails/month

• Starter: $15/month for 10,000 emails/month

• Professional: $75/month for 100,000 emails/month

• Premier: Custom pricing for high-volume senders

SMTP relay services like SMTP2Go appeal to organizations wanting infrastructure control without building email servers internally. The platform handles technical complexity—IP warmup, authentication configuration, bounce processing—while providing visibility into delivery performance.

For e-commerce brands without dedicated email operations teams, SMTP relay services may add complexity without addressing the core Promotions tab challenge. However, brands with technical resources and multi-platform email needs benefit from centralized relay management.

6. Mailchimp — Established Email Marketing Platform

Mailchimp remains one of the most recognized email marketing platforms, offering drag-and-drop campaign builders, audience management, and automation workflows for businesses across industries.

Platform Features:

• Visual email editor with templates and drag-and-drop design

• Audience segmentation and list management

• Marketing automation workflows

• Landing page and signup form builders

• Basic analytics and reporting

• Extensive integration marketplace

Pricing:

• Free: Up to 500 contacts with limited features

• Essentials: Starting at $13/month

• Standard: Starting at $20/month

• Premium: Starting at $350/month

Mailchimp's strength lies in accessibility—non-technical users can build campaigns without developer resources. The platform's template library and automation features handle common email marketing needs for small to mid-sized businesses.

However, Mailchimp doesn't specialize in e-commerce or Klaviyo-level retention marketing sophistication. The platform lacks native Shopify/WooCommerce integration depth, and deliverability optimization focuses on general best practices rather than Gmail tab placement targeting.

Comparing Features for E-commerce Needs

Mailchimp vs. Klaviyo comparison:

• E-commerce Integration: Mailchimp offers basic integration, while Klaviyo provides deep native integration

• Revenue Attribution: Mailchimp has limited capabilities, while Klaviyo offers comprehensive tracking

• Behavioral Triggers: Mailchimp provides standard triggers, while Klaviyo offers advanced options

• Deliverability Tools: Mailchimp has general tools, while Klaviyo provides ISP-level tracking

7. MailerLite — Cost-Effective Email Marketing for Growing Brands

MailerLite offers similar functionality to Mailchimp at lower price points, making it attractive for budget-conscious businesses building email programs.

Core Offerings:

• Drag-and-drop email editor with responsive templates

• Automation workflows for common sequences

• Landing pages and website builder features

• Subscriber management and segmentation

• A/B testing capabilities

• Basic deliverability reporting

Budget-Friendly Pricing:

• Free: Up to 500 subscribers

• Growing Business: $10/month (500 subscribers)

• Advanced: $20/month (500 subscribers)

• Pricing scales with subscriber count

MailerLite competes on value, providing essential email marketing features without premium pricing. For brands early in their email marketing journey, MailerLite offers sufficient functionality before needs outgrow the platform.

The trade-off involves depth of e-commerce features. MailerLite lacks the advanced segmentation, predictive analytics, and revenue attribution that platforms like Klaviyo provide—capabilities that become essential as email programs mature and revenue attribution becomes critical.

8. Klaviyo Native Deliverability Hub — Built-In Monitoring at No Extra Cost

Klaviyo's native Deliverability Hub provides e-commerce brands monitoring capabilities included with existing subscriptions, eliminating additional vendor costs for basic deliverability visibility.

Included Features:

• ISP-level inbox placement tracking across Gmail, Yahoo, Outlook

• Google Postmaster Tools integration for Gmail reputation data

• Microsoft SNDS integration for Outlook metrics

• Bounce and complaint rate monitoring

• Domain and IP reputation tracking

• Actionable recommendations for improvement

Pricing:

• Free plan available

• Paid plans start at $20/month for 5,000 emails per month

For 160,000+ e-commerce businesses already using Klaviyo, the native Deliverability Hub provides valuable baseline monitoring without adding vendor complexity. The tools help identify when deliverability problems exist and track reputation metrics over time.

However, Klaviyo's native tools focus on monitoring and recommendations—they don't actively move emails from Promotions to Primary tabs. The platform tells you where emails land but doesn't change placement through algorithmic optimization.

Limitation Context:

Klaviyo's Deliverability Hub serves as an excellent diagnostic tool, showing which ISPs present challenges and how reputation evolves. For active inbox placement optimization—particularly Gmail Primary tab targeting—specialized solutions like Mailmend complement Klaviyo's monitoring with algorithmic placement technology.

Understanding Mailgun Optimize and the Need for Alternatives

Mailgun's infrastructure, which serves over 150,000 businesses, handles over 450 billion emails annually. Mailgun Optimize is a suite of tools that leverages this infrastructure to help businesses improve their email deliverability. The platform provides email validation, inbox placement testing, spam trap monitoring, and blocklist tracking—tools designed primarily for technical teams managing transactional email at scale.

However, e-commerce brands face a specific challenge Mailgun Optimize doesn't directly address: Gmail's Promotions tab categorization. When promotional emails land in the Promotions folder instead of the Primary inbox, open rates drop significantly, reducing revenue from email marketing campaigns.

The Mailgun Optimize Starter plan at $99/month includes 5,000 email validations, 50 inbox placement tests, and integration with Google Postmaster Tools. While comprehensive for developer-focused deliverability monitoring, these features require technical knowledge and don't specifically target promotional email placement optimization.

For e-commerce brands using Klaviyo, the gap between Mailgun Optimize's transactional focus and promotional email needs creates opportunity for specialized alternatives.

Traditional warmup approaches requiring 1-2 weeks don't fit tight timelines. Mailmend's 24-hour results make it the only option for brands needing immediate placement improvement without content changes.

Explore partnership opportunities if you're an agency serving e-commerce clients facing deliverability challenges.

Frequently Asked Questions

What is the main difference between an SMTP service and an email marketing platform?

SMTP services like SMTP2Go and Mailgun provide email delivery infrastructure—the technical layer that sends emails from your systems to recipients. Email marketing platforms like Mailchimp and Klaviyo add campaign management, audience segmentation, automation workflows, and analytics on top of sending capabilities. SMTP services require more technical configuration but offer greater control, while marketing platforms prioritize ease of use for non-technical teams.

How does Mailmend move emails from the Promotions tab to the Primary tab without changing content?

Mailmend uses proprietary algorithmic technology that embeds custom code into Klaviyo email templates. This code counteracts signals Gmail's algorithms use to categorize emails as promotional. The process involves testing emails against rotating test inboxes, analyzing the "promotional threshold" factors, and generating account-specific code that helps emails land in Primary inboxes—all without modifying email copy, design, or sending practices.

Are Mailgun Optimize alternatives suitable for businesses of all sizes?

Different alternatives serve different business scales. Mailchimp and MailerLite offer free tiers for small businesses building email programs. Klaviyo's native tools work for any Klaviyo subscriber. Mailmend targets seven-to-eight-figure e-commerce brands where Gmail placement directly impacts revenue. Mailgun Optimize and enterprise SendGrid tiers fit organizations with dedicated technical resources and high-volume needs. Match your choice to current email volume, technical capabilities, and growth trajectory.

What kind of results can I expect from using a specialized deliverability solution like Mailmend?

According to Mailmend's published case studies, e-commerce brands report open rate improvements ranging from 21-82% and click-through rate increases of 30-67%. Dr. Squatch achieved 112% email revenue increase within 24 hours. Results vary based on current placement rates, email frequency, and audience engagement patterns. Mailmend's Klaviyo-native A/B testing allows brands to measure exact lift by comparing campaigns with and without the placement optimization active.

Can I integrate Mailmend with email service providers other than Klaviyo?

Currently, Mailmend integrates exclusively with Klaviyo. The platform's proprietary technology is purpose-built for Klaviyo's infrastructure, enabling the 5-minute setup that distinguishes it from solutions requiring API configuration. Brands using other ESPs like Mailchimp, SendGrid, or custom solutions would need to evaluate alternatives like Mailgun Optimize for general deliverability monitoring or consider migrating promotional email to Klaviyo to access Mailmend's Primary tab placement capabilities.

How important is A/B testing in choosing an email deliverability solution?

A/B testing capabilities prove critical for measuring actual revenue impact from deliverability improvements. Mailmend's Klaviyo-native integration enables direct comparison of campaigns with and without placement optimization—showing exactly how Primary tab placement affects open rates, clicks, and attributed revenue within Klaviyo's existing analytics. Without A/B testing, deliverability improvements remain theoretical rather than measurable, making it difficult to justify ongoing investment in optimization tools.