Zeptomail is Zoho’s dedicated transactional email service. It does not handle marketing email at all; Zoho offers that separately through Zoho Campaigns. The strict separation is the product thesis: by refusing bulk promotional traffic on its infrastructure, Zeptomail maintains cleaner IP reputation for the transactional messages (password resets, form confirmations, order receipts) that need to land in inboxes immediately.
The pricing model is unusual in this category: credits at $2.50 per 10,000 emails with no monthly subscription. Credits expire six months after purchase. One credit covers 10,000 emails; a WordPress site sending 500/month uses 3,000 before the credit expires, wasting the remainder but spending only $2.50 over six months. That is not the cheapest option; SMTP2GO offers 1,000/month indefinitely for free – but it is among the cheapest for sites that exceed SMTP2GO’s free cap without needing a full monthly plan.
Zeptomail is available across Zoho’s multi-region infrastructure, which includes data centers in the US, EU, India, Australia, Japan, and Canada, giving GDPR-constrained European sites a local processing option that Postmark and most smaller transactional relays lack.
SMTP settings
| Setting | Value |
|---|---|
| Host | smtp.zeptomail.com |
| Port | 587 (TLS) or 465 (SSL) |
| Encryption | TLS 1.2 |
| Username | emailapikey |
| Password | Send Mail Token (from Mail Agent settings) |
Zeptomail does not use account passwords for SMTP authentication. Each Mail Agent generates its own Send Mail Token, a long API credential used as the SMTP password. The fixed username is emailapikey for all connections. If your mailer plugin has a character-length limit on the password field, Zeptomail provides a shorter token variant in the dashboard.
IP restriction is available as a security measure: you can lock a Mail Agent’s credentials to specific sending IPs so a leaked token cannot be used from other servers.
Mail Agents
Zeptomail’s credential model is built around “Mail Agents,” separate sending channels within your account. Each Agent has its own SMTP/API credentials, suppression list, sending limits, and tracking configuration. You can associate one or more verified domains with each Agent.
The practical use for WordPress: create one Agent per site (or per purpose, such as one for order confirmations and one for password resets). If one site’s sending triggers complaints, only that Agent’s reputation is affected; the others continue independently. This is analogous to Mailgun’s per-domain credentials or Postmark’s Servers concept, but scoped by purpose rather than domain alone.
Pricing
| Item | Cost |
|---|---|
| Credits | $2.50 per 10,000 emails |
| Monthly fee | None |
| Trial | 10,000 emails free (expires 1 month after signup) |
| Credit expiry | 6 months from purchase |
| Auto top-up | Available (auto-purchase when credits run low) |
| Dedicated IP | Annual add-on (select data centers) |
| Custom pricing | Available for high-volume senders |
The model is flat: buy credits, use them, buy more when they run out.
The one-month trial window is aggressive. Most competitors offer 30 days with no pressure or indefinite free tiers. With Zeptomail, you have one month to evaluate with 10,000 emails, then you buy credits or sending stops.
The cost math at WordPress-typical volumes: a site sending 2,000 emails/month uses one credit ($2.50) every five months. A site sending 200 emails/month uses 1,200 emails of a 10,000-credit bundle before expiry, 88% waste, though only $2.50 lost. For context, that same 200/month site pays nothing on SMTP2GO’s free tier or on Brevo’s 300/day free allowance.
Zeptomail offers auto top-up to prevent sending interruption: credits are purchased automatically when the balance runs low. Without auto top-up enabled, exhausted credits mean sending fails and WordPress email silently stops until credits are replenished. Enable auto top-up on any production site.
No refunds on unused credits upon cancellation.
DNS authentication
Zeptomail requires DKIM verification before sending. The setup:
- Add a DKIM TXT record to your domain’s DNS (selector is customisable; 1024-bit or 2048-bit key length)
- Add a CNAME record for bounce/return-path handling
- Verify in the Zeptomail dashboard (allow 24-48 hours for propagation)
SPF is not strictly required. Zeptomail recommends DKIM and CNAME records only, to avoid redundancy with SPF includes from other services on the same domain. This is sensible advice for domains that already have a crowded SPF record.
After verifying DNS, test with swaks that outgoing messages pass DKIM alignment. For help with DNS record setup, see our WordPress email DNS guide.
WordPress integration
Three paths:
Zoho ZeptoMail plugin – The 
dedicated WordPress plugin (slug: transmail, 5,000+ active installs) connects via Zeptomail’s API using a Send Mail Token. No SMTP configuration needed – enter the token, select your verified From address, done. This is the fastest path for Zeptomail specifically.
Zoho Mail plugin – The Zoho Mail for WordPress plugin (20,000+ active installs) connects to Zoho Mail accounts, not Zeptomail. See the disambiguation section below if you are unsure which product you need.
Generic SMTP – Any mailer plugin (WP Mail SMTP, FluentSMTP, Post SMTP) can connect to smtp.zeptomail.com using the SMTP settings above. FluentSMTP also has a native Zeptomail/API integration. This is the universal fallback; see our compatible plugin list.
Zeptomail vs Zoho Mail
These are distinct products sharing a parent company:
- Zoho Mail is a mailbox service (inbox, calendar, contacts), Zoho’s equivalent to Google Workspace or Microsoft 365. Pricing starts at $1/month per user. WordPress integration is via OAuth and the Zoho Mail API, sending through your Zoho mailbox with that mailbox’s sending limits.
- Zeptomail is a transactional relay (no mailbox, no inbox). Send-only, with pay-per-email pricing and infrastructure isolated from marketing traffic. Higher volume capability, purpose-built for application-generated email.
If your WordPress site uses Zoho Mail for team email and you send under 50 transactional messages a day, sending through your Zoho Mail account via the Zoho Mail plugin is sufficient. If you need higher volume, want deliverability isolation from your mailbox reputation, or run multiple sites, Zeptomail is the correct choice.
Assessment
Zeptomail is a good fit for WordPress transactional email in one specific scenario: sites already in the Zoho ecosystem that need a transactional relay without a monthly subscription commitment. The transactional-only policy is genuine, not a marketing claim but an architectural decision that keeps the sending infrastructure isolated from bulk campaigns.
The cases where Zeptomail fits well:
- WordPress sites in Zoho Workplace environments (coherent vendor stack, single billing relationship)
- Sites sending 1,000-10,000 emails/month where SMTP2GO’s free tier is too small but a monthly plan feels excessive
- Operators who want strict transactional/marketing separation without managing it themselves
- European or APAC sites needing local data processing (multi-region availability)
The cases where other options are better:
- Low volume, cost-sensitive: SMTP2GO’s free tier (1,000/month, no expiry, no credit card) is the better default for sites under that threshold. No expiry risk, no waste.
- Deliverability-focused at scale: Postmark shares Zeptomail’s transactional-only philosophy with a longer track record, better-documented deliverability infrastructure, and deeper WordPress ecosystem support. $15/month for 10,000 emails.
- Developer infrastructure: Mailgun or Amazon SES for high-volume or complex routing requirements where per-message cost and API flexibility matter more than simplicity.
- Free tier with no catches: SMTP2GO or Brevo (300/day free) if the budget is zero.
For most WordPress sites without an existing Zoho relationship, SMTP2GO or Postmark are stronger defaults. Zeptomail earns its place when the Zoho ecosystem context or the no-subscription pricing model matches the operator’s constraints.
For the broader setup that places Zeptomail inside the WordPress email stack, see the WordPress email setup guide.
Pricing verified June 2026 against zoho.com/zeptomail/pricing.html. SMTP settings verified against Zeptomail SMTP/API documentation. WordPress plugin data from wordpress.org.