TL;DR:
- mutt and sendmail need a local MTA and your own server setup; ktx connects directly to KIRIM.EMAIL cloud, nothing to configure.
- Install in one command:
curl -fsSL https://raw.githubusercontent.com/kirimemail/ktx/main/install.sh | bash - AI agents can use ktx via SKILLS.md with zero onboarding, purpose-built for agentic email workflows.
If you’ve ever searched “how to send email from terminal Linux,” you’ve probably seen the same answers: mutt, msmtp, or mailx. All fine for 2010. In 2026, they share the same problem.
ktx is the official KIRIM.EMAIL CLI tool for sending email from the terminal. Connects directly to the cloud, no local MTA, no manual SPF/DKIM configuration.
Why mutt and sendmail Are Not Enough for Modern Developers
mutt and sendmail require a local Mail Transfer Agent configured from scratch: Postfix, SPF, DKIM, reverse DNS.
On most cloud VPS providers (AWS, GCP, DigitalOcean, Linode), port 25 is blocked by default. That means mutt and sendmail still need an external relay on top. Two configuration layers, two points of failure.
The bigger problem: no delivery log. If an email doesn’t arrive, you don’t know where it failed. In mutt: clean. In sendmail: clean. No error, no trace.
ktx is different. No local MTA. Direct connection to KIRIM.EMAIL’s cloud infrastructure. Every delivery event is visible via ktx logs.
ktx vs Other Ways to Send Email from the Terminal
ktx | mutt / msmtp | sendmail / mailx | curl + API | |
|---|---|---|---|---|
| Setup | 1 curl command | Configure .msmtprc | Install MTA + configure | Manual coding |
| Needs own server? | No | Yes | Yes | No |
| Real-time delivery log | Built-in | None | None | None |
| 9-event webhook | Built-in | No | No | No |
| Email validation | Built-in | No | No | No |
| AI agent ready | Yes (SKILLS.md) | No | No | Partial |
| Sandbox testing | Built-in | No | No | No |
One capability that doesn’t exist anywhere else: Sandbox Recipients. Register up to 10 test addresses as a safe zone during development. AI agents can send as many emails as needed without touching real inboxes.
How to Install ktx and Send Your First Email from Terminal
One command, works on Linux, Mac, and Windows:
curl -fsSL https://raw.githubusercontent.com/kirimemail/ktx/main/install.sh | bashCreate your config file at ~/.ktxrc:
{
"username": "your-username",
"token": "your-api-token",
"base_url": "https://smtp-app.kirim.email",
"domain": "yourdomain.com"
}Send your first email:
ktx send \
-from [email protected] \
-to [email protected] \
-subject "Hello from the terminal" \
-text "This email was sent directly from the terminal."Monitor delivery logs in real time:
ktx logs --followSetup done. No Postfix, no relay configuration, no support ticket about reverse DNS.
Why AI Agents Building Agentic Workflows Need ktx
AI agents need to send email without opening a browser, without logging into a dashboard, and without a human in the loop at every step.
Most email services are built for humans who click dashboards. Agents that should operate autonomously end up stalling at steps that could be fully automated.
ktx solves this with two things. First, every email operation is available as a terminal command that agents can call directly. Second, every repository (ktx, Python SDK, Node.js SDK, PHP SDK) ships with a SKILLS.md file.
SKILLS.md is a compact guide for LLMs. Load it into Claude, Cursor, or Windsurf context, and the agent immediately knows the right command for every task. No manual onboarding. No explaining things one by one.
ktx supports 9 webhook events: delivered, opened, clicked, bounced, temporary_fail, permanent_fail, unsubscribed, rejected, sent. Agents react automatically: bounces get flagged in your system, temporary_fail triggers a retry without anyone watching a dashboard.
Why Your Server’s IP Reputation Matters More Than Your Code
This part rarely shows up in CLI email tutorials.
When you send email through mutt or a raw SMTP relay, your cloud server’s IP is the sender. Shared cloud IPs on AWS us-east-1, GCP, or DigitalOcean are frequently on spam blocklists, because thousands of other services (and bad actors) share the same IP ranges.
Your email can be perfectly formatted, SPF and DKIM configured correctly, and still land in spam because of someone else’s behavior on a neighboring IP.
ktx routes through KIRIM.EMAIL’s dedicated sending infrastructure. Your server’s IP is no longer in the equation. 34,000+ businesses have routed email through this infrastructure over 10 years, building the sender reputation that benefits every sender on the platform.
For agentic workflows sending hundreds of emails in sequence, this is not a minor detail. It is the difference between a workflow that completes in seconds and one that silently fails mid-run.
Because when it comes to SMTP that works without the setup headache: KIRIM.EMAIL.
Frequently Asked Questions About ktx
Q: What’s the difference between ktx and mutt or sendmail?mutt and sendmail require a locally configured Mail Transfer Agent: Postfix, SPF/DKIM, reverse DNS. ktx connects directly to KIRIM.EMAIL’s cloud, no server setup required, no DNS configuration, sending immediately through infrastructure with established IP reputation across 34,000+ active senders.Q: Does ktx work on Windows?Yes. The ktx install script supports Linux, Mac, and Windows. Full instructions per platform are at github.com/kirimemail/ktx.Q: How many sandbox recipients can I register?Up to 10 email addresses. Each address confirms before it can receive test emails. Available in your KIRIM.EMAIL Dev dashboard under Sandbox Recipients in the left sidebar.Q: Do I need a KIRIM.EMAIL account to use ktx?Yes. You need an API token from a KIRIM.EMAIL Dev account. Generate the token in your dashboard after signup, then store it in ~/.ktxrc or as the environment variable KIRIM_TOKEN.Q: What is SKILLS.md and how do I use it?SKILLS.md is a purpose-built guide for LLMs and AI agents. It contains a capability list, example commands, and enough context for an agent to start working immediately. Load it into Claude, Cursor, or Windsurf context and the agent knows how to use ktx without any manual explanation.Q: How do I view email delivery logs from the terminal?Use ktx logs for a static log view, or ktx logs --follow for real-time monitoring. Logs cover all events including delivered, bounced, opened, and clicked.Q: Does ktx support sending to multiple recipients at once?Yes. ktx send supports multiple recipients, and ktx validate can validate a list of addresses before a batch send.
Get Started
ktx 1.0.3 is available now. Three steps:
- Install with the curl command above
- Register Sandbox Recipients in your dashboard for safe testing
- Load SKILLS.md into your AI agent and let it work
Questions about a specific use case or need help with setup: reach the KIRIM.EMAIL team at [email protected].
