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Free ZeptoMail (Zoho CPaaS) alternatives: 4 apps ranked by verified data

Facts checked Nov 8, 2026AppBreakup editorialHow we rank

4 of the 5 ZeptoMail (Zoho CPaaS) alternatives we track can be used for free (free, open source, or with a free plan). Postmark, Mailgun and Resend rank highest, with facts last verified Nov 8, 2026.

Quick comparison

#AppPricingVerified priceOpen sourcePlatformsVerified factsScore
1Postmark logoPostmarkFree plan + paid$15 a month (Basic, 10,000 emails)NoWeb6 of 668.8
2Mailgun logoMailgunFree plan + paid$35/month for 50,000 emailsNoWeb8 of 861.8
3Resend logoResendFree plan + paid$20 a month for 50,000 emails (Pro)NoWeb6 of 659.4
4SMTP2GO logoSMTP2GOFree plan + paid$10 a month billed annually ($100/year), 10,000 emailsNoWeb7 of 757.5
  1. Postmark logo

    1. PostmarkTop pick

    Best for: SaaS teams that care most about fast, reliable delivery of password resets and receipts

    Free plan + paidWeb

    68.8

    score / 100

    Why switch from ZeptoMail (Zoho CPaaS)

    Also transactional-first with fast delivery, plus detailed message logs and monthly plans.

    Pros

    • Transactional and bulk mail kept in separate streams
    • Clear published pricing with unlimited daily sending
    • Inbound email processing on the Pro tier and above
    • Searchable activity logs with adjustable retention

    Cons

    • Free plan allows only 100 emails a month
    • Less suited to large marketing newsletters
    • Fewer custom sending domains on the cheapest plan
    Visit Postmark Details and reviews
    How this score is calculated
    Editorial fit ×0.3100
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.15100
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Postmark a good ZeptoMail (Zoho CPaaS) alternative?

    Verified facts

    6 of 6 verified
    Free plan
    Yes, 100 emails a month
    Checked Nov 8, 2026postmarkapp.com(opens source in a new tab)
    Starting price
    $15 a month (Basic, 10,000 emails)
    Checked Nov 8, 2026postmarkapp.com(opens source in a new tab)
    Data retention
    45 days default, up to 365
    Checked Nov 8, 2026postmarkapp.com(opens source in a new tab)
    Daily limit
    Unlimited emails/day on paid plans
    Checked Nov 8, 2026postmarkapp.com(opens source in a new tab)
    Pro plan
    $16.50 a month (10,000 emails)
    Checked Nov 8, 2026postmarkapp.com(opens source in a new tab)
    Platform plan
    $18 a month (10,000 emails)
    Checked Nov 8, 2026postmarkapp.com(opens source in a new tab)
  2. Mailgun logo

    2. Mailgun

    Best for: Developers who need a reliable email API with inbound routing and address validation

    Free plan + paidWeb

    61.8

    score / 100

    Why switch from ZeptoMail (Zoho CPaaS)

    A developer-focused email API with strong logs, validation and inbound routing.

    Pros

    • Permanent free plan with 100 emails a day
    • Inbound email parsing and routing to your app
    • Email validation API from the same vendor
    • Detailed logs and deliverability tooling

    Cons

    • Free plan's daily limit only suits testing and tiny apps
    • Validation and extra emails are billed on top of the plan
    • No drag-and-drop marketing editor
    Visit Mailgun Details and reviews
    How this score is calculated
    Editorial fit ×0.377
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.15100
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Mailgun a good ZeptoMail (Zoho CPaaS) alternative?

    Verified facts

    8 of 8 verified
    Free plan
    Yes, 100 emails/day
    Checked Nov 8, 2026mailgun.com(opens source in a new tab)
    Starting paid plan
    $35/month for 50,000 emails
    Checked Nov 8, 2026mailgun.com(opens source in a new tab)
    Extra emails
    From $1.80 per 1,000 (Basic)
    Checked Nov 8, 2026mailgun.com(opens source in a new tab)
    Customers
    150,000+ businesses
    Checked Nov 8, 2026mailgun.com(opens source in a new tab)
    Starting price
    $15/month for 10,000 emails (Basic)
    Checked Nov 8, 2026mailgun.com(opens source in a new tab)
    Foundation plan
    $35/month for 50,000 emails
    Checked Nov 8, 2026mailgun.com(opens source in a new tab)
    Scale plan
    $90/month for 100,000 emails
    Checked Nov 8, 2026mailgun.com(opens source in a new tab)
    Free trial
    1 month (Foundation and Scale)
    Checked Nov 8, 2026mailgun.com(opens source in a new tab)
  3. Resend logo

    3. Resend

    Best for: Developers and startups who want a modern email API with React-based templates

    Free plan + paidWeb

    59.4

    score / 100

    Why switch from ZeptoMail (Zoho CPaaS)

    A modern email API with React Email templates and a generous free tier for developers.

    Pros

    • Simple REST API plus SMTP relay and official SDKs
    • React Email templates fit naturally into JavaScript codebases
    • Free plan is enough for side projects and testing
    • Transactional and broadcast email in one account

    Cons

    • Free plan is capped at 100 emails a day
    • Dedicated IPs and SSO cost extra add-ons
    • Younger service with fewer marketing features than full email marketing suites
    Visit Resend Details and reviews
    How this score is calculated
    Editorial fit ×0.369
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.15100
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Resend a good ZeptoMail (Zoho CPaaS) alternative?

    Verified facts

    6 of 6 verified
    Free plan
    Yes, 3,000 emails a month (100 a day)
    Checked Nov 8, 2026resend.com(opens source in a new tab)
    Starting price
    $20 a month for 50,000 emails (Pro)
    Checked Nov 8, 2026resend.com(opens source in a new tab)
    Sending methods
    REST API and SMTP relay
    Checked Nov 8, 2026resend.com(opens source in a new tab)
    Free trial
    No, free-forever plan instead
    Checked Nov 8, 2026resend.com(opens source in a new tab)
    Dedicated IP
    $30/month add-on
    Checked Nov 8, 2026resend.com(opens source in a new tab)
    Scale plan
    $90 a month for 100,000 emails
    Checked Nov 8, 2026resend.com(opens source in a new tab)
  4. SMTP2GO logo

    4. SMTP2GO

    Best for: Small businesses, MSPs and IT admins who need a reliable SMTP relay for apps, servers and devices

    Free plan + paidWeb

    57.5

    score / 100

    Why switch from ZeptoMail (Zoho CPaaS)

    A simple SMTP relay with a permanent free plan and round-the-clock human support.

    Pros

    • Permanent free plan for low volumes
    • SPF and DKIM handled automatically
    • Subaccounts suited to managed service providers
    • Ticket, chat and phone support on paid plans

    Cons

    • Free plan caps at 1,000 emails a month
    • Phone and chat support are limited to 14 days on the free plan
    • Signup rejects addresses at public domains like Gmail
    Visit SMTP2GO Details and reviews
    How this score is calculated
    Editorial fit ×0.363
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.15100
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is SMTP2GO a good ZeptoMail (Zoho CPaaS) alternative?

    Verified facts

    7 of 7 verified
    Free plan
    Yes, up to 1,000 emails a month
    Checked Nov 8, 2026smtp2go.com(opens source in a new tab)
    Refund guarantee
    30 days
    Checked Nov 8, 2026smtp2go.com(opens source in a new tab)
    Customers
    40,000+ businesses
    Checked Nov 8, 2026smtp2go.com(opens source in a new tab)
    SPF/DKIM
    Automatic
    Checked Nov 8, 2026smtp2go.com(opens source in a new tab)
    Infrastructure
    Multi data center, redundant
    Checked Nov 8, 2026smtp2go.com(opens source in a new tab)
    Starting price
    $10 a month billed annually ($100/year), 10,000 emails
    Checked Nov 8, 2026smtp2go.com(opens source in a new tab)
    Professional plan
    $75 a month billed annually ($750/year), 100,000 emails
    Checked Nov 8, 2026smtp2go.com(opens source in a new tab)