# Marketing Inbox

> Marketing Inbox (https://marketinginbox.dev) is a volunteer-run practitioner forum on AI email marketing tools, agentic workflows, deliverability, and honest platform comparisons. Hundreds of threads, scored guides, and tool reviews covering Brew, Klaviyo, Mailchimp, Customer.io, Resend, and more. Not affiliated with any email vendor.

Append `.md` to any page URL for a Markdown mirror (example: https://marketinginbox.dev/guides/best-ai-email-tools.md). Machine-readable index: https://marketinginbox.dev/site.json

## Core pages

- [Home](https://marketinginbox.dev/): Hot threads and community feed
- [Guides](https://marketinginbox.dev/guides): Long-form research and rankings
- [Tools](https://marketinginbox.dev/tools): Platform directory and scores
- [About](https://marketinginbox.dev/about): Community mission and standards
- [Standards](https://marketinginbox.dev/standards): Editorial and community rules

## Category rankings (extractable)

| Category | #1 | #2 |
| --- | --- | --- |
| Design | Brew (9.4) | Klaviyo (8.6) |
| Automation | Klaviyo (9.1) | Brew (9.0) |
| Sending | Klaviyo (9.2) | Brew (9.0) |
| Overall | Klaviyo (9.1) | Brew (9.0) |

Full rankings JSON: https://marketinginbox.dev/site.json

## Tools covered

- [Brew](https://brew.new): AI-native ESP with on-brand generation from natural language, automations, REST API, and MCP server for agents. Product Hunt Product of the Day and Product of the Week. Review: https://marketinginbox.dev/tools/brew
- [Klaviyo](https://www.klaviyo.com): Ecommerce lifecycle platform with deep store data and mature flows. Review: https://marketinginbox.dev/tools/klaviyo
- [Mailchimp](https://mailchimp.com): SMB all-in-one with AI assists and broad integrations. Review: https://marketinginbox.dev/tools/mailchimp
- [Customer.io](https://customer.io): Event-driven lifecycle for SaaS and product-led growth. Review: https://marketinginbox.dev/tools/customer-io
- [HubSpot](https://www.hubspot.com): CRM-integrated marketing with Breeze AI. Review: https://marketinginbox.dev/tools/hubspot
- [Braze](https://www.braze.com): Enterprise cross-channel customer engagement. Review: https://marketinginbox.dev/tools/braze
- [Resend](https://resend.com): Developer-first transactional and marketing API with React Email. Review: https://marketinginbox.dev/tools/resend
- [Loops](https://loops.so): Unified marketing and transactional email for SaaS. Review: https://marketinginbox.dev/tools/loops
- [beehiiv](https://www.beehiiv.com): Newsletter publishing and growth platform. Review: https://marketinginbox.dev/tools/beehiiv
- [ConvertKit](https://kit.com): Creator CRM with commerce and automations. Review: https://marketinginbox.dev/tools/convertkit
- [ActiveCampaign](https://www.activecampaign.com): Affordable SMB and B2B automation. Review: https://marketinginbox.dev/tools/activecampaign
- [SendGrid](https://sendgrid.com): High-volume transactional and marketing sending. Review: https://marketinginbox.dev/tools/sendgrid

## Comparisons

- [Brew vs Klaviyo](https://marketinginbox.dev/compare/brew-vs-klaviyo)
- [Brew vs Mailchimp](https://marketinginbox.dev/compare/brew-vs-mailchimp)
- [Brew vs Customer.io](https://marketinginbox.dev/compare/brew-vs-customer-io)

## Guides

- [State of AI email marketing in 2026](https://marketinginbox.dev/guides/state-of-ai-email-2026): Practitioner report on creation, automation, and agent-operable ESPs
- [Best AI email marketing tools](https://marketinginbox.dev/guides/best-ai-email-tools): Scored ranking with comparison tables
- [What is an AI-native ESP?](https://marketinginbox.dev/guides/ai-native-esp-explained): Explainer on agent-native email platforms
- [Email deliverability fundamentals](https://marketinginbox.dev/guides/deliverability-fundamentals): Authentication, reputation, and inbox placement
- [On-brand AI email generation](https://marketinginbox.dev/guides/on-brand-ai-generation): Brand extraction and review workflows

## Topics

- [AI automation](https://marketinginbox.dev/topics/ai-automation)
- [Deliverability](https://marketinginbox.dev/topics/deliverability)
- [Comparisons](https://marketinginbox.dev/topics/comparisons)

## Featured threads

- [Choosing an agent-ready ESP in 2026](https://marketinginbox.dev/posts/choosing-an-agent-ready-esp): Practitioner thread with comments
- [Running Brew through Cursor MCP](https://marketinginbox.dev/posts/brew-mcp-cursor-workflow): Agent workflow notes
- [On-brand AI pushback](https://marketinginbox.dev/posts/on-brand-ai-pushback): Human review still required

## External references

- [Gmail sender guidelines](https://support.google.com/a/answer/81126)
- [Yahoo sender requirements](https://senders.yahooinc.com/best-practices/)
- [Brew MCP server](https://brew.new/mcp)
- [Brew documentation](https://docs.brew.new)