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Email Warmup

Email warmup gradually increases your sending volume over time, building a positive sender reputation with email providers. This is essential when using a new email address or domain for outreach.

Why Warmup Matters​

When you start sending emails from a new address or domain, email providers (Gmail, Outlook, Yahoo) have no history to judge your reputation. Sending too many emails too quickly can result in:

  • Emails landing in spam folders
  • Your domain being blacklisted
  • Temporary or permanent sending blocks

Warmup solves this by starting with a small volume and gradually increasing it over 2-4 weeks.

How CronDB Warmup Works​

Daily Volume Ramping​

CronDB automatically increases your daily send limit following a proven schedule:

WeekDaily Send LimitCumulative Total
Week 110-20 emails/day~100
Week 230-50 emails/day~350
Week 375-100 emails/day~950
Week 4150-200 emails/day~2,100
Week 5+Full capacityYour plan limit

The exact ramp depends on your plan's daily limit and the email provider you are using.

Warmup Emails​

During the warmup period, CronDB sends automated warmup emails to a network of trusted inboxes. These emails:

  • Are opened and read (signals positive engagement to email providers)
  • Receive replies (builds conversation history)
  • Are moved out of spam if they land there (trains spam filters)
  • Use realistic content and subject lines
Warmup Pool

CronDB's warmup network includes thousands of real inboxes across Gmail, Outlook, Yahoo, and other providers. This simulates genuine email activity to build your reputation naturally.

Setting Up Warmup​

  1. Go to Sequences → Settings → Email Accounts
  2. Select your connected email account
  3. Click Enable Warmup
  4. Choose a warmup duration:
    • Standard (4 weeks) — Recommended for new domains
    • Accelerated (2 weeks) — For domains with some existing reputation
    • Custom — Set your own ramp schedule
  5. Click Start Warmup

Sequences

Domain Health Checks​

CronDB continuously monitors your email domain's authentication records:

SPF (Sender Policy Framework)​

SPF tells email providers which servers are allowed to send email on behalf of your domain.

  • Status: Pass — Your SPF record is correctly configured
  • Status: Fail — Add CronDB's sending servers to your SPF record
  • How to fix — Add include:spf.crondb.com to your DNS TXT record

DKIM (DomainKeys Identified Mail)​

DKIM adds a digital signature to your emails, verifying they have not been tampered with.

  • Status: Pass — Your DKIM is properly set up
  • Status: Fail — Add the DKIM key provided by CronDB to your DNS
  • How to fix — Add the CNAME record shown in your email account settings

DMARC (Domain-based Message Authentication)​

DMARC tells email providers what to do with emails that fail SPF or DKIM checks.

  • Status: Pass — DMARC policy is in place
  • Status: Missing — No DMARC record found
  • Recommended policy — Start with v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com
Authentication Required

All three records (SPF, DKIM, DMARC) must be properly configured before starting sequences. CronDB will warn you if any are missing or misconfigured.

Auto-Pause on High Bounce​

CronDB automatically pauses sending if it detects deliverability problems:

TriggerThresholdAction
Bounce rate>5% in 24 hoursPause sending, notify you
Spam complaints>0.3%Pause sending, notify you
Blacklist detectionAny major blacklistPause sending, notify you

When auto-pause triggers:

  1. All active sequences for that email account are paused
  2. You receive an email and in-app notification
  3. The issue is described with recommended actions
  4. You must manually resume after addressing the problem

Reputation Tracking​

Monitor your sender reputation in Sequences → Settings → Email Health:

MetricHealthyWarningCritical
Bounce rate<2%2-5%>5%
Spam rate<0.1%0.1-0.3%>0.3%
Open rate>20%10-20%<10%
Blacklists012+

The dashboard shows a daily trend for each metric, helping you spot problems early.

Best Practices​

  1. Always warm up new accounts — Even if you have sent emails before, a new connection to CronDB should be warmed up
  2. Do not skip warmup — The short-term delay pays off with much better deliverability long-term
  3. Fix authentication first — Ensure SPF, DKIM, and DMARC pass before starting warmup
  4. Monitor daily — Check your email health dashboard during the warmup period
  5. Start sequences gradually — Even after warmup, ramp up your sequence volume gradually

Next Steps​

Try it now →