Is there an importer for MailerSend?

No. The dashboard's importer covers Resend, SendGrid and Postmark. From MailerSend, add your domains, import your suppressions through the API or as CSV, recreate your templates and switch your sending code or SMTP settings.

Can coss.com send newsletters as well as transactional email?

Yes. Broadcasts and marketing sends use the same API key and SDK as transactional email, on a separate stream with its own reputation, so newsletter complaints never hold up password resets.

Does coss.com have inbound routing like MailerSend?

coss.com receives every message for an environment's addresses, stores it and sends an email.received webhook; your code decides what to do with it. There are no route rules or forwarding to another address.

Can coss.com send SMS outside the US and Canada?

Yes. Every organization starts with the US and Canada, and owners and admins can allow other priced countries. The numbers themselves are US and Canadian, and toll-free numbers only send to those two countries.

Does coss.com work with SMTP like MailerSend?

Yes. smtp.coss.com accepts TLS on port 465 and STARTTLS on 587 (2465 and 2587 also work), with the username coss and an API key as the password.

coss.com vs MailerSend

MailerSend is a transactional email API with SMS in the US and Canada. coss.com adds contacts, broadcasts and sub-accounts on the same key.

MailerSend covers transactional email well: an API and SMTP relay, a drag-and-drop builder, inbound routes on every plan, and SMS and WhatsApp as extras. For newsletters it points you to MailerLite. coss.com keeps transactional and marketing email in one account, gives platforms sub-accounts with their own reputation, and logs every request and webhook on every plan.

At a glance

MailerSend's side was checked on November 3, 2026 against its own pages. Prices are list prices.

Feature	coss.com	MailerSend
Pricing model	Per recipient, with no volume tiers to pick: $0.40 per 1,000 recipients for the first 1,000,000; $0.30 per 1,000 recipients from 1,000,001 to 10,000,000; $0.22 per 1,000 recipients beyond 10,000,000. Paid plans start at $25/month, all of it spendable on usage	Hobby $7/month for 5,000 emails; Starter from $35/month and Professional from $110/month for 50,000; extra emails $1.50 per 1,000 on Hobby, $1.30 on Starter and Professional at 50,000
Free tier	Free plan: 3,000 email recipients a month, 3,000 received emails a month and 3 inboxes; 1 sending domain	500 emails a month, 1 domain, 1 template, 100 API requests a day, 1 day of activity data; a credit card is required
Transactional email	REST API and an SMTP relay (smtp.coss.com), batch and scheduled sends, idempotency keys, templates with versions and locales	Email API and SMTP relay; drag-and-drop, HTML and rich-text builders, dynamic templates and split testing; bulk emailing from Hobby
Marketing email	Contacts with custom properties, audiences, segments, topics with a hosted preference center and double opt-in, broadcasts on a separate marketing stream	Built for transactional email: its help pages recommend MailerLite for newsletters and campaigns
Receiving email	Every environment has its own address under coss.com's inbound domain, or receive at your own domain with one MX record; an email.received webhook, content and attachments through the API	Inbound routes on every plan: an @inbound.mailersend.net address or your domain with an MX record; messages parsed to JSON, posted to a webhook or forwarded by email
SMS	SMS (US): $0.0142 per segment; SMS (other countries): $0.022 to $0.1134 per segment, carrier fees included; live SMS on paid plans. The US and Canada by default; others once you allow them, from the priced list on coss.com/pricing	US and Canada only, transactional only; 100 messages a month on Starter, 150 on Professional, then $1.40 per 100; phone numbers $2 each
WhatsApp	—	An add-on on Hobby, Starter and Professional
Multi-tenant sending	Sub-accounts on Scale and Enterprise: each with its own domains, SES tenant, reputation, quotas and suppression list (transactional email)	1 domain on Hobby, 10 on Starter, unlimited on Professional, with extra domains at $4; no sub-accounts on its pricing page
Dedicated IPs	An add-on on Scale and Enterprise: Amazon SES managed dedicated IPs, warmed up automatically	An add-on for Enterprise accounts sending over 100,000 emails a week
Activity history	Every API request, email event and webhook attempt of an environment, searchable and exportable; log drains on Scale and Enterprise	1 day on Free and Hobby, 7 days on Starter, 30 days on Professional; up to 365 days as an add-on, from $5
Webhooks	Standard Webhooks signatures, automatic retries, test events and `coss listen` to forward events to localhost	HMAC-SHA256 of the body in a Signature header; retries for about 3 days; 1 webhook on Free and Hobby, 50 on Starter, unlimited on Professional
SDKs	TypeScript, plus generated SDKs for Python, Go, Ruby, PHP, Java and .NET; Laravel, Rails and Django mail drivers; a CLI and an MCP server	Node.js, Python, Java, Laravel, PHP, Go and Ruby; a CLI and an MCP server

Which to choose

Both are good at what they do. Here is where each one fits better.

Choose MailerSend when

Designers build your emails
MailerSend has drag-and-drop, HTML and rich-text builders and split testing. coss.com templates are HTML and text with variables, edited in the dashboard or through the API.
You need WhatsApp
WhatsApp is an add-on on MailerSend's paid plans. coss.com doesn't send WhatsApp messages.
You want verification and blocklist tools
MailerSend sells email verification credits on every plan and includes blocklist monitoring. coss.com has email checks in Risk and DMARC reports, but no blocklist monitoring.
You send a small, steady volume
Hobby is a flat monthly fee for 5,000 emails, for a single domain.

Choose coss.com when

Newsletters from the same account
Contacts, audiences, segments, topics with a hosted preference center and broadcasts live next to your transactional email, on a separate stream with its own reputation.
You send for your own customers
Sub-accounts on Scale and Enterprise each get their own domains, SES tenant, reputation, quotas and suppressions, and pause on their own bounces and complaints, not yours.
SMS beyond North America, or for marketing
MailerSend's SMS is US and Canada, and transactional only. coss.com can send to other priced countries once you allow them, and its registration form has a marketing use case.
Logs on every plan
Each environment's log holds every API request, email event and webhook attempt, Free included, instead of a retention window chosen by plan.
Sandbox environments
Sandbox environments with coss_test_ keys are free, run the same API, send nothing and simulate outcomes for email and SMS.

Moving from MailerSend

1
Add and verify your domains
There is no importer for MailerSend: the dashboard's importer covers Resend, SendGrid and Postmark. Add each domain in coss.com and publish its DNS records. coss.com's DKIM records sit next to MailerSend's, so you can keep sending there until you switch.
Read the guide
2
Bring over suppressions
Page through MailerSend's hard bounce, spam complaint, unsubscribe and blocklist endpoints and import the addresses with coss.email.suppressions.import, or as CSV on the Suppressions page.
Read the guide
3
Recreate your templates
Recreate each template in coss.com's template language, declare its variables, publish it and send it with template_id and variables. Or send HTML or React Email from your code.
Read the guide
4
Switch sending, routes and webhooks
Send with coss.email.send() or SMTP at smtp.coss.com. Replace inbound routes with a receiving domain and an email.received handler, and point webhook handlers at coss.com's events and signatures. SMS needs a coss.com number and its own registration.
Read the guide

Questions

Is there an importer for MailerSend?: No. The dashboard's importer covers Resend, SendGrid and Postmark. From MailerSend, add your domains, import your suppressions through the API or as CSV, recreate your templates and switch your sending code or SMTP settings.
Can coss.com send newsletters as well as transactional email?: Yes. Broadcasts and marketing sends use the same API key and SDK as transactional email, on a separate stream with its own reputation, so newsletter complaints never hold up password resets.
Does coss.com have inbound routing like MailerSend?: coss.com receives every message for an environment's addresses, stores it and sends an email.received webhook; your code decides what to do with it. There are no route rules or forwarding to another address.
Can coss.com send SMS outside the US and Canada?: Yes. Every organization starts with the US and Canada, and owners and admins can allow other priced countries. The numbers themselves are US and Canadian, and toll-free numbers only send to those two countries.
Does coss.com work with SMTP like MailerSend?: Yes. smtp.coss.com accepts TLS on port 465 and STARTTLS on 587 (2465 and 2587 also work), with the username coss and an API key as the password.

Sources

MailerSend's facts were checked on November 3, 2026; their pages are the final word on their prices and features.

The coss.com side

Try coss.com next to MailerSend.

A development key costs nothing and delivers nothing, so you can compare with real code.

Add coss.com to this project: read https://coss.com/llms.txt, get a development key with `npx coss-cli init --agents`, and build and test with it.