Email Platform Comparison

Free tiers, API access, MCP servers & paid pricing for digital product creators

Must-Haves Checklist

API
Add contacts & manage campaigns programmatically
Inboxing
Strong deliverability — not landing in spam
Custom Forms
Add contacts via API, not just provider forms
Opt-in
Single OR double opt-in option

Free Tier Comparison

PlatformFree SubsFree Sends/moAPI on Free?Add via API?Opt-in ControlDeliverability
Kit
Creator-focused
1,000Unlimited broadcasts Full CRUD Single & double per form 🟢 Excellent
Brevo
Priced by sends
Unlimited~9,000 (300/day) Full CRUD + consent groups Single & double via consent 🟢 Very good
MailerLite
API = paid only
2502,500 Paid only On paid plans Single & double 🟢 Strong
Mailchimp
Tiny free tier
250500 (250/day) Marketing API Single & double per audience 🟢 Industry-leading
Loops
API-first
1,0004,000 Clean REST API ⚠️ Single only (no built-in double) 🟡 Good (newer)
Resend
Dev infra
1,000 contacts~3,000 (100/day) Audiences API DIY via API 🟢 Good (newer)
Beehiiv
Newsletter-first
2,500Unlimited Subs CRUD (no Send API) Full CRUD + double_opt_override Single & double (per sub) 🟢 Very good
Substack
Walled garden
UnlimitedUnlimited No official API Internal endpoints only (fragile) ⚠️ Double opt-in setting exists 🟡 Spam issues reported
⚠️ Key takeaway: Mailchimp (250 subs) and MailerLite (250 subs, no API on free) are effectively unusable on free tiers. Substack has no official API (community hacks exist but are fragile). Beehiiv's API works on free (subscription CRUD), but Send API requires Enterprise. The real contenders for API-driven workflows are Kit, Brevo, Loops, and Resend.

Pricing at Scale (Monthly Cost by Subscriber Count)

SubscribersKitBrevoMailerLiteLoopsMailchimpBeehiiv
500FreeFreeFree*FreeFreeFree
1,000FreeFree$10Free$13Free
2,500$41Free†$25$49$45Free
5,000$66$9‡$39$79$75$43
10,000$100$18$73$149$110$43
25,000$166$18$159$249$270$43

* MailerLite: no API on free tier   † Brevo free: unlimited subs, 300 emails/day cap   ‡ Brevo Starter: $9/mo for 5K emails

💡 Brevo's pricing model is fundamentally different: It charges by emails sent, not subscribers. You can have 50,000 contacts for free — you only pay when you blast. At 25K subs sending weekly, that's ~100K emails/mo = $18/mo on Standard. Kit would be $166/mo for the same list.

API & MCP Access

PlatformREST APIOfficial SDKsMCP ServerAPI Highlights
Kit V4 (all plans) Ruby, Node (community) Official Docs MCP + Kit MCP (Creator+) Subscribers, broadcasts, sequences, tags, forms, webhooks. Upsert contacts. 140 custom fields.
Brevo V3 (all plans) Node, Python, PHP, Go Community 4 MCP repos (low stars) Contacts, campaigns, transactional, SMS, WhatsApp. Batch 1K emails/request. Consent groups. Sandbox mode.
MailerLite V2 (paid only) Node, Python None Subscribers, campaigns, automations, segments, webhooks. Clean docs.
Mailchimp Marketing API (all plans) Node, Python, PHP Community LokiMCPUniverse Most mature email API. Contacts, campaigns, automations, segments, reports. Mandrill for transactional.
Loops REST (all plans) Node, Python + CLI tool None Contacts, events, transactional email, webhooks. Best DX. CLI for management.
Resend REST (all plans) Node, Python, Ruby, Go, PHP None API-first. Emails, audiences, contacts, webhooks. React Email. SMTP relay. Batch send.
Beehiiv ⚠️ Subs API free, Send API Enterprise None official Official Read on free, Write on Scale ($43/mo) Subscriptions CRUD, custom fields, tags, segments, double_opt_override. Webhooks on Scale+.
Substack No official API None Community 4+ repos (fragile, internal API) Undocumented /api/v1/ with session cookie auth. Draft/publish via community MCPs. No subscriber mgmt API. Anti-spam blocks server signups.
🤖 MCP (Model Context Protocol) lets AI assistants like Claude or Hermes directly manage your email platform. Kit is the only one with an official MCP. Brevo and Mailchimp have community-built MCPs. For everything else, I'd use the REST API directly via scripts.

Platform Deep-Dives

Loops — Best API Developer Experience

API-first Modern DX

Built for SaaS/product companies. Cleanest API in the space. Event-triggered workflows. CLI tool for management. All features on free plan.

API Details

REST API at app.loops.so/api. Node & Python SDKs + CLI tool. Contacts, events, transactional email, webhooks, contact properties, mailing lists. Event-triggered workflows.

Pricing

Free: 1K subs, 4K sends/mo, all features, "Powered by Loops" footer. Paid starts ~$49/mo (2K subs). Scales to ~$249/mo at 25K subs.

Pros & Cons

✅ Best API/CLI DX. ✅ All features on free. ✅ Event-triggered workflows. ❌ No double opt-in toggle. ❌ No landing pages/forms (build your own). ❌ Newer platform, less deliverability history. ❌ Expensive at scale.

Beehiiv — Best Free Newsletter Growth Tools

2,500 free subs API on all plans Has MCP

Built for newsletter growth with referral programs, ad network, and boost marketplace. Generous free tier (2,500 subs, unlimited sends, subscription API). Send API is Enterprise-only.

API Details

REST API on ALL plans (including free). Create/update subscriptions, custom fields, tags, segments. double_opt_override field: "on", "off", or "not_set" per subscription. Send API (programmatic email sending) is Enterprise-only. Official MCP server at developers.beehiiv.com/_mcp/server — read access on free, write access on Scale. Webhooks on Scale+.

Pricing

Free: 2,500 subs, unlimited sends, web builder, email editor, API (subscription CRUD), read MCP. Scale: $43/mo (100K subs, ad network, boosts, automations, surveys, webhooks, MCP write access, 3 team seats). Max: $96/mo (remove branding, 10 publications, unlimited seats, Getty credits). Enterprise: custom (dedicated IP, send API, SSO).

Pros & Cons

✅ 2,500 free subs + unlimited sends. ✅ API on all plans (subscription CRUD). ✅ Official MCP server. ✅ double_opt_override field for per-subscriber opt-in control. ✅ Built-in growth tools (referrals, boosts, ads). ❌ Send API = Enterprise only. ❌ No transactional email. ❌ More newsletter-focused than SaaS/digital product focused.

Substack — Simplest, But a Walled Garden

No API No automation

Zero-friction newsletter platform. Free to use, Substack takes 10% of paid subscriptions. But zero API, zero automation, zero programmatic control. You're locked into their ecosystem.

API Details

❌ No official public API. Undocumented internal API at /api/v1/ (session cookie auth, fragile, could break anytime). 4+ community MCP servers exist for draft/publish management. No official subscriber management API. Anti-spam heuristics block server-to-server signups.

Pricing

Free: unlimited subs, unlimited sends. If you go paid: Substack takes 10% + Stripe fees (2.9% + $0.30 + 0.7% recurring). Effective total: 13-16% of revenue. At $5/mo subs, ~20% lost to fees. Break-even vs flat-rate platforms: below ~$330-490/mo in subscription revenue Substack is cheaper.

Pros & Cons

✅ Truly free (no limits on subs or sends). ✅ Built-in paid subscription system. ✅ Built-in network/discovery. ✅ Zero setup. ✅ Optional double opt-in setting. ❌ No official API (internal endpoints fragile). ❌ No automation/sequences. ❌ 13-16% effective revenue cut on paid subs. ❌ Deliverability complaints (Gmail spam issues). ❌ Zero control over sending infrastructure.

Resend — Email Infrastructure (Not an Autoresponder)

Developer infra Build everything yourself

Email sending infrastructure for developers. Excellent API, React Email integration, SMTP relay. But no sequences, no automation builder, no forms. You build everything in code.

Pros & Cons

✅ Best developer SDKs (Node, Python, Ruby, Go, PHP). ✅ React Email for templates. ✅ Transactional + marketing. ❌ No automation builder. ❌ No forms or landing pages. ❌ 100/day on free. ❌ You build sequences yourself in code.

Recommendations by Use Case

🥇 Best for SaaS + Digital Products
Kit
Free → $33/mo Creator
Purpose-built for creators selling digital products. Official MCP means AI can manage campaigns. API on all plans. Sequences, automations, purchase tracking built-in. The $33/mo Creator plan unlocks everything.
🥇 Best Value at Scale
Brevo
Free → $18/mo Standard
Unlimited contacts on free. Charges by sends not subs — $18/mo covers 25K subs sending weekly. Includes transactional email (critical for SaaS). SMS/WhatsApp bonus. Community MCP available.
🥈 Best for Newsletter Growth
Beehiiv
Free → $43/mo Scale
2,500 free subs + unlimited sends. API on all plans (subscription CRUD). Official MCP server. Built-in referral program, boost marketplace, and ad network. Send API is Enterprise-only. Best if newsletter IS the business.
🥉 Best API DX
Loops
Free → $49/mo
Cleanest API + CLI. All features on free. Event-triggered workflows. But no forms/landing pages, no double opt-in, and expensive at scale. Best for dev-heavy teams building custom frontends.
🎯 Bottom Line:

Use Kit for the brand where you're actively selling digital products (courses, ebooks). The Creator plan ($33/mo) is worth it — sequences, automations, purchase tracking, and the official MCP let me manage campaigns directly.

Use Brevo for the brand you're building from scratch. Unlimited contacts on free means you can grow aggressively. When you outgrow free, $18/mo Standard gets you automation + A/B testing. And it includes transactional email, so if you're also running a SaaS app, you don't need a second service.

Skip Substack (no official API, 13-16% revenue cut, deliverability issues), skip Mailchimp (tiny free tier, expensive), skip MailerLite (no API on free).

MCP & API Quick Reference

What can I (Hermes) or Claude do via API/MCP?

Kit: Create/update subscribers, send broadcasts, manage sequences & tags, create forms, pull analytics. Official MCP on Creator plan ($33/mo). Community MCP on GitHub (docs-only).
Brevo: Create/update contacts, send campaigns & transactional email, manage consent groups, SMS/WhatsApp. Community MCP repos on GitHub. Full SDK in Node/Python/PHP/Go.
Loops: Create/update contacts, send events, trigger transactional email, manage lists & workflows. CLI tool. No MCP but clean REST API I can script.
Resend: Send emails, manage audiences/contacts, webhooks. Best SDKs. No MCP. I'd build sequences in code.
MailerLite: Full API but PAID ONLY. No MCP.
Beehiiv: Subscription API on all plans (free included). Send API = Enterprise only. Official MCP: read access on free, write on Scale ($43/mo). double_opt_override field for opt-in control.
Substack: No official API. 4+ community MCPs (draft/publish via undocumented internal API, session cookie auth, fragile). No subscriber management via API. Could break anytime.