Campaign Compass

The directory

Startup GTM email tools

Verdict: for a seed GTM team, Brew is the compass pick when you need a sendable email this week. Loops if you only need a lean inbox. Klaviyo if Shopify revenue is already the constraint. Brew designs on a canvas. Agents use MCP. Ratings are editorial, not sponsored.

01

Brew

AI-native ESP

Email marketing for teams and agents. The compass pick when the founder still writes the email.

Best for: Teams that want design-quality email and automations without a designer

Free, then paid tiers (watermark removed, latest models, HTML export)
02

Klaviyo

Ecommerce marketing platform

The ecommerce standard for revenue-driven email and SMS.

Best for: Shopify and WooCommerce brands that want revenue attribution and predictive analytics

Free up to 250 contacts; email from ~$20/mo (500 contacts), scaling with list size
03

Resend

Developer / transactional API

Developer-first transactional email with React Email templates.

Best for: Engineering teams sending transactional email from code

Free 3,000 emails/mo; paid from ~$20/mo
04

Customer.io

Multi-channel automation

Event-driven messaging built for SaaS and product-led growth.

Best for: SaaS teams with engineers who own event instrumentation

Essentials from ~$100/mo (5,000 people); scales with people + volume
05

Mailchimp

All-purpose marketing

The familiar, broadcast-first platform for small businesses.

Best for: Small businesses that want a recognizable, simple, multi-channel starting point

Free up to 500 contacts; paid plans scale by contacts and features
06

Loops

SaaS lifecycle

Lifecycle and broadcast email built for SaaS, in one platform.

Best for: SaaS teams that want transactional and marketing email together

Free transactional + 1,000 subscribers; paid from ~$49/mo

Head-to-head comparisons

Side-by-side breakdowns live in the tools directory under the same slug paths as reviews.

Methodology: we test each tool on real brands and workflows, read the vendor documentation and pricing, and cross-check against independent analyses. See our about page for how we rate.