Built for High Deliverability

Cold Email API
That Actually Lands in Inbox

Email infrastructure for sales outreach and lead generation.
Domain warm-up, deliverability monitoring, compliance tools.
Built for teams who need emails in the inbox, not spam.

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95%+
Inbox Placement Rate
Auto
Domain Warm-up
Real-time
Spam Score Check
GDPR
Compliant

Why Most Cold Emails Fail

Land in Spam

67% of cold emails never reach the inbox. Poor domain reputation, no warm-up, bad authentication setup.

Domain Blacklisted

Send too many emails too fast on a new domain, and you're blacklisted. Game over for that domain.

Compliance Issues

No unsubscribe link? GDPR violation. CAN-SPAM violation. Legal trouble and massive fines.

Everything You Need for Cold Email at Scale

Purpose-built infrastructure for sales outreach. Not just another email API.

Automatic Domain Warm-up

Gradually increase sending volume over 2-4 weeks. Build domain reputation automatically. We handle the warm-up schedule for you.

  • Automated warm-up schedule
  • Start with 10-20 emails/day, scale to thousands
  • Monitor reputation in real-time
  • Prevent domain blacklisting

Real-Time Deliverability Monitoring

Track inbox placement, spam rates, and domain reputation. Get alerts before issues impact your campaigns.

  • Inbox vs spam folder tracking
  • Spam score analysis per email
  • Domain reputation monitoring
  • Bounce and complaint tracking

Domain Health Checker

Verify SPF, DKIM, DMARC records automatically. Check if your domain is on any blacklists. Fix issues before they hurt deliverability.

  • SPF, DKIM, DMARC validation
  • Blacklist monitoring (50+ lists)
  • DNS record health checks
  • Auto-fix suggestions

Built-in Compliance

GDPR, CAN-SPAM, CASL compliant out of the box. One-click unsubscribe, preference management, automatic suppression lists.

  • Auto-add unsubscribe links
  • Global suppression list
  • Preference center included
  • GDPR consent tracking

Advanced Personalization

Dynamic variables, conditional content, custom fields. Make every email feel personal, not automated.

  • Unlimited custom variables
  • Conditional content blocks
  • First name, company, role, etc.
  • Fallback values for missing data

Smart Rate Limiting

Control sending speed per domain. Prevent looking like a spammer. Spread emails throughout the day for better engagement.

  • Per-domain sending limits
  • Time-based spreading (9am-5pm)
  • Randomized send times
  • Hourly throttling

How to Send Cold Emails with Sendmator

1

Verify Your Domain

Add SPF, DKIM, DMARC records. We validate everything for you. Domain health check included.

SPF: v=spf1 include:sendmator.com ~all DKIM: Auto-generated keys DMARC: v=DMARC1; p=quarantine;
2

Start Warm-up (Auto)

We automatically warm up your domain. Start small, scale gradually. Takes 2-4 weeks.

Week 1: 10-20 emails/day
Week 2: 50-100 emails/day
Week 3: 200-500 emails/day
Week 4+: Unlimited
3

Send Cold Emails

Use the API or dashboard. We handle deliverability, compliance, and tracking automatically.

await sendmator.messages.send({ to: lead.email, template: "cold-outreach", variables: { name: lead.name } });

Who Uses Sendmator for Cold Email

Sales Teams

Outbound prospecting, lead generation, follow-up sequences. Reach decision-makers at scale.

SaaS Companies

Product launches, feature announcements, reactivation campaigns. Get users back.

Recruiting Agencies

Candidate outreach, job opportunities, talent acquisition. Build your pipeline.

Important: Cold Email Compliance

Cold emailing is legal when done correctly. You MUST:

  • Have a legitimate reason to contact (not random spam)
  • Include unsubscribe link in every email (we add this automatically)
  • Honor unsubscribe requests within 10 days
  • Include your physical business address
  • Don't use deceptive subject lines
  • Be transparent about who you are

Sendmator helps you stay compliant, but ultimately YOU are responsible for following laws in your jurisdiction (CAN-SPAM, GDPR, CASL, etc.).

Cold Email Best Practices

Do This

  • Personalize every email - Use first name, company name, specific details
  • Warm up your domain - Start slow, build reputation over weeks
  • Keep it short - 50-150 words max, clear call-to-action
  • Send from real person - john@company.com, not noreply@
  • A/B test subject lines - Test what works for your audience
  • Follow up 2-3 times - Most replies come from follow-ups
  • Clean your list - Remove bounces and unsubscribes
  • Monitor metrics - Open rates, reply rates, spam complaints

Don't Do This

  • Buy email lists - Recipe for spam complaints and blacklisting
  • Use spam trigger words - "Free", "Guarantee", "Act now", "Limited time"
  • Send from new domain immediately - Always warm up first
  • Send same email to everyone - Personalization matters
  • Ignore unsubscribes - Legal requirement and ethical duty
  • Use misleading subject lines - Illegal and destroys trust
  • Send large attachments - Often blocked, looks like spam
  • Blast thousands per day - Start slow, scale gradually

Frequently Asked Questions

Is cold emailing legal?

Yes, when done correctly. You must include unsubscribe links, honor opt-outs, and follow CAN-SPAM (US), GDPR (EU), and CASL (Canada) laws. Sendmator provides compliance tools, but you're responsible for following laws in your jurisdiction.

How long does domain warm-up take?

Typically 2-4 weeks. We start with 10-20 emails per day and gradually increase. Rushing this process can get your domain blacklisted. Patience pays off with 95%+ inbox placement rates.

What's a good open rate for cold emails?

Industry average is 15-25% open rate and 1-5% reply rate. Highly personalized, targeted campaigns can achieve 40%+ opens and 10%+ replies. Quality over quantity always wins.

Can I use Sendmator for spam?

Absolutely not. We have zero tolerance for spam. Accounts sending unsolicited bulk emails, purchased lists, or violating anti-spam laws will be immediately suspended. We monitor for abuse.

Do I need multiple domains for cold email?

Best practice is to use a separate domain for cold outreach (e.g., if your main domain is company.com, use getcompany.com or trycompany.com for outreach). This protects your main domain's reputation.

What happens if someone marks my email as spam?

Spam complaints are tracked and impact your domain reputation. Keep spam rates below 0.1%. We alert you if rates spike. High spam rates can lead to account suspension to protect our infrastructure.

Ready to Land in the Inbox?

Start sending cold emails that actually get read and replied to.

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No credit card required • 1,000 free emails/month • Cancel anytime

Related Resources

Transactional Email

For operational emails

Domain Health

Check SPF, DKIM, DMARC

Email Validator

Clean your email lists

Documentation

API reference & guides