StackBest email (transactional & marketing) for solo founders
Your app needs two kinds of email: transactional (password resets, receipts, magic links) and marketing (newsletters, launch announcements, drip sequences). Most tools do one well and the other badly, so many solo founders end up paying for two services without realizing the overlap. The real costs hide in overage rates, contact-count billing, and free tiers that quietly expired or cap you at 100 sends a day.
| Tool | Free tier | Paid from | Best for |
|---|---|---|---|
 Resend$20/mo | $20/mo | Solo devs shipping a SaaS who want transactional email working today with zero email expertise | |
| $15/mo | Founders whose password resets and receipts absolutely must land in the inbox | ||
 Loops$49/mo | $49/mo | SaaS founders who want all product email in one tool and can absorb $49/mo | |
 SendGrid$19.95/mo | $19.95/mo | Founders already on Twilio or expecting 100K+ emails/mo soon | |
 Mailgun$15/mo | $15/mo | Backend-heavy founders who want raw SMTP/API sending and inbound routing cheap | |
 Kit (ConvertKit)$33/mo | $33/mo | Creator-founders monetizing an audience with sequences and digital products | |
 Buttondown$9/mo | $9/mo | Developer-founders running a simple newsletter next to their product for under $10/mo | |
 Beehiiv$43/mo | $43/mo | Founders making the newsletter itself a growth channel or revenue product |
Start with Resend free (3,000 transactional emails/mo) for app email and Beehiiv Launch or Buttondown for the newsletter, total $0 to $9/mo. When you pass 3,000 transactional sends, Resend Pro at $20/mo is the obvious upgrade; if deliverability of receipts and resets becomes business-critical, Postmark at $15/mo is the safer engine.
Consolidate onto Loops ($49/mo) only once you are juggling drip sequences plus transactional in two tools and the time cost exceeds the price gap. Skip SendGrid unless you expect 100K+ emails a month: its free tier is now a 60-day trial and support is thin at the low end.
ResendDefault pickFree tierAsk about these tools
The fine print, tool by tool
Resend$20/mo+
Resend is an email API built for developers, with React Email templates and an SDK you can wire into your app in an afternoon. Solo founders pick it when they need password resets and receipts sending today and do not want to learn email infrastructure first.
$20/mo (50,000 transactional emails)
3,000 emails/mo, capped at 100 emails/day, 1 domain, 1,000 marketing contacts
Transactional and marketing are two separate meters. Free marketing tier is 1,000 contacts; at 1,001 contacts you jump to a $40/mo marketing plan (good to 5,000) even if you already pay $20/mo for transactional. Marketing plans run up to $650/mo for 150,000 contacts. Dedicated IP is a $30/mo add-on that requires Scale ($90/mo) and 3,000+ daily sends. Automations over 10,000 runs/mo cost extra. No annual discount published.
- + Best developer experience in the category: React Email templates, clean SDK, setup in under 30 minutes
- + Free tier (3,000/mo) is permanent, unlike SendGrid's 60-day trial
- + Overage is a predictable $0.90 per 1,000 emails instead of a hard cutoff
- − Marketing plans are billed separately from transactional: 5,000 contacts costs another $40/mo on top of Pro
- − 100 emails/day cap on the free tier breaks any launch-day spike
Postmark$15/mo+
Postmark is a transactional email service that stakes its whole reputation on getting your app's emails into the inbox fast. Solo founders pick it when a missed password reset or receipt would cost them a customer.
$15/mo (10,000 emails)
100 emails/mo, no expiration, no overages allowed
The jump from free (100/mo) to paid (10,000/mo at $15) has no middle step. No annual plans exist. Unused emails do not roll over. DMARC monitoring starts at $14/mo per domain. Dedicated IPs start at $50/mo and require 300,000+ emails/mo. Pro tier at $16.50/mo drops overage to $1.30 per 1,000 and adds inbound processing, usually worth the extra $1.50.
- + Reputation for the fastest, most reliable transactional inbox delivery in the industry
- + Separate message streams keep transactional deliverability isolated from marketing sends
- + Simple flat plans, no contact-count billing at all
- − Free tier is only 100 emails per month, useless beyond initial testing
- − Overage on Basic is $1.80 per 1,000 emails, double Resend's $0.90
Loops$49/mo+
Loops is one email tool for SaaS products that covers transactional, marketing, and lifecycle drip emails together. Solo founders pick it when running Resend plus a separate newsletter tool starts costing more time than the $49/mo consolidation price.
$49/mo (Starter, 5,000 contacts, unlimited sends)
1,000 contacts, 4,000 sends/mo, all features, Loops branding in footer
Priced purely on subscribed contacts, so prune inactive contacts before each billing cycle. Growth runs $99 to $249/mo and Scale is $399/mo, a steep curve for a solo budget. Annual and biennial billing lower the monthly rate. The free tier is generous on features but the send cap, not the contact cap, is what you hit first.
- + One tool for transactional, marketing, and lifecycle drips, replacing a Resend + newsletter tool combo
- + Transactional email is free on paid plans, no separate volume meter
- + Unlimited sends on paid plans, so a big launch broadcast costs nothing extra
- − First paid tier is $49/mo, more than Resend Pro plus Buttondown combined
- − Free plan's 4,000 sends/mo is roughly one weekly email to 1,000 people, nothing left for onboarding flows
SendGrid$19.95/mo+
SendGrid is Twilio's email sending platform, built for volumes far beyond what a one-person company sends. Solo founders pick it mainly when they are already inside the Twilio ecosystem or planning for six-figure monthly send volumes.
$19.95/mo (Essentials, 50,000 emails)
Overage on Essentials is $1.30 per 1,000 (billed next cycle). Marketing Campaigns is a second meter (free only to 2,000 contacts and 6,000 emails/mo), so the advertised $19.95 rarely matches the real bill once you add a list. Accounts created via third parties cannot use overages and just stop sending.
- + Battle-tested deliverability infrastructure that scales past anything a solo founder will send
- + Pro plan ($89.95/mo) includes a dedicated IP and 2,500 email validations
- + Both marketing and transactional under one account
- − The permanent free tier is gone since 2025; after 60 days you pay or stop sending
- − Support on cheap plans is notoriously slow, and account suspensions can take days to resolve
Mailgun$15/mo+
Mailgun is a sending API and SMTP relay aimed at engineers who want raw email plumbing, including inbound routing and parsing. Solo founders pick it when they need programmatic control over sending and receiving without paying for a marketing suite they will not use.
$15/mo (Basic, 10,000 emails)
100 emails/day (about 3,000/mo), 1 domain, 1-day log retention
The 1-day log retention on plans under $35/mo is the trap: you cannot investigate delivery issues after the fact. Only Scale ($90/mo) includes a dedicated IP; Foundation does not, and additional IPs cost $59/mo each. Email validations cost extra ($0.80 to $1.20 per 100). No real marketing suite; campaigns need sibling product Mailjet, a second subscription. Free plan allows only 1 user.
- + Permanent free tier at 100 emails/day, enough for an MVP's auth emails
- + Strong sending API with good routing and inbound parsing for the price
- + Foundation ($35/mo) includes 50,000 emails, 5-day logs, 1,000 domains, and 5,000 validations, with the first month free
- − Log retention is 1 day on Free and Basic; debugging yesterday's bounce means paying $35/mo for 5-day logs
- − Basic overage is $1.80 per 1,000, twice Resend's rate
Kit (ConvertKit)$33/mo+
Kit is a marketing platform built for creators who sell to an audience, with sequences, landing pages, and digital product checkout in one place. Solo founders pick it when the audience is the business and they want to monetize a list, not send app emails.
$33/mo (Creator, 1,000 subscribers)
Newsletter plan: up to 10,000 subscribers, unlimited broadcasts, landing pages and forms, but only 1 basic automation
The odd part: free supports 10,000 subscribers but paid tiers price from a 1,000-subscriber base, so upgrading with a big free list triggers a large jump (roughly $100+/mo at 10,000 subscribers, versus Beehiiv's flat $43). Annual billing gives 2 months free ($390/yr Creator, $790/yr Pro). Commerce fee of 3.5% + $0.30 beats Stripe direct out of your margin, and Paid Recommendations take 23.5%. Watch the automation limit, not the subscriber limit.
- + Free plan allows 10,000 subscribers, the biggest free audience cap in this list
- + Unlimited landing pages and forms on free, so you can build a waitlist with zero other tools
- + Sell digital products on the free plan (3.5% + $0.30 per transaction)
- − The free plan is bait for automations: 1 basic automation only, and paid starts at $33/mo for just 1,000 subscribers
- − No transactional email API, so you still need Resend or Postmark for app emails
Buttondown$9/mo+
Buttondown is a small, developer-friendly newsletter service where you write in markdown and pay only for active subscribers. Solo founders pick it when they want a simple product newsletter for under $10/mo without a marketing platform attached.
$9/mo (Basic, 1,000 subscribers)
100 subscribers, markdown editor, hosted archives, custom sending domain
Base price is honest but the a-la-carte add-ons are the trap: tagging, paid subscriptions, analytics, or comments add $9/mo each; automations, multiple newsletters, and custom domain archives add $29/mo each; whitelabeling is $79/mo. Price your needed add-ons before comparing with flat-rate rivals. Sending more than one email per day to your full list needs a custom plan. 50 percent off for registered nonprofits.
- + Cheapest paid newsletter here: $9/mo for 1,000 subscribers, less than half Kit or Beehiiv
- + Bills only active subscribers, so dead emails do not inflate your invoice
- + Markdown-first writing and a real API, built for developers
- − Feature add-ons stack fast: automations cost $29/mo extra, turning $9 into $38
- − No transactional API for app emails, newsletters only
Beehiiv$43/mo+
Beehiiv is a newsletter platform with built-in growth and monetization features like an ad network, referral boosts, and paid subscriptions with no platform cut. Solo founders pick it when the newsletter itself is meant to become a growth channel or a revenue line.
$43/mo (Scale, up to 100,000 subscribers)
Launch plan: 2,500 subscribers, unlimited sends, custom domain, website, analytics
The free tier is the best value in this list until you need automations. The branding-removal paywall at $96/mo is the sneaky tier gap: most Scale features are enough, but white-labeling alone costs another $53/mo. Annual discount is thin: $71/yr saved on Scale ($517/yr), $157/yr on Max. The Send API is Enterprise-only, so it cannot handle your app's transactional email.
- + Free plan with 2,500 subscribers and unlimited sends beats every paid entry tier here for pure newsletters
- + 0% platform cut on paid subscriptions (Stripe fees only), versus Substack's 10%
- + Scale covers up to 100,000 subscribers at a flat $43/mo, no per-subscriber creep
- − Automations and paid subscriptions require Scale at $43/mo, a big jump from $0
- − Removing beehiiv branding requires Max at $96/mo
[ Partnerships ] Building a tool solo founders should know about?
DM @monjodavKnow what your whole stack costs
StackTracker adds up every one of these, plus your hours.
Start tracking · $9/mo