If you’ve just started sending emails from a new domain (or you normally send low volumes), it’s common to see inconsistent deliverability in your first weeks.
Email providers like Gmail, Yahoo, and Outlook need time to trust new senders — and until that trust is built, your emails may:
- land in Spam instead of Inbox
- show up in Inbox but with images hidden
- experience lower opens or delayed delivery
This guide explains sender reputation, what email warm-up means, and which Hostinger Reach features help you improve deliverability faster.
What is sender reputation?
Sender reputation is a trust score email providers build for your domain over time.
When you send emails, providers evaluate signals like:
- how many emails you send (and how suddenly volume increases)
- how many people open and reply
- whether users mark your email as Not spam
- bounce rates (invalid email addresses)
- spam complaints and unsubscribes
- email quality (formatting, spelling, “spam-like” content)
A weak or “new” reputation often leads to more spam filtering — even if your setup is correct.
Why inbox placement differs across Gmail, Yahoo, and Outlook
Email providers don’t all use the same filtering rules, so results can vary.
For example, in early tests (common for new senders):
- Yahoo: one email may land in spam while the next lands in the inbox
- Gmail: emails land in inbox, but images may be hidden
- Outlook: emails may go to spam more aggressively
This doesn’t always mean something is broken — it often means your sending reputation is still being established.
What is email warm-up?
Email warm-up is a strategy where you slowly increase sending volume while building positive engagement (opens, replies, “Not spam” actions).
It helps prove to mailbox providers that your new domain is safe, wanted, and consistent.
✅ Warm-up is one of the most effective ways to improve deliverability in your first weeks.
Recommended warm-up plan (first 2–3 weeks)
Week 1: Start small
- Send only to a small group of trusted recipients
- Use simple emails (welcome emails, product updates, helpful messages)
- Avoid large campaigns immediately
✅ Goal: steady opens and replies.
Week 2: Increase gradually
- Increase sending volume step-by-step
- Keep engagement high
- Avoid sudden spikes in email volume
✅ Goal: stable inbox placement across providers.
Week 3+: Scale campaigns carefully
- Start with your most engaged audience first
- Grow your campaign volume gradually
- Monitor bounces, opens, and spam placement
✅ Goal: long-term sender trust.
Ask recipients to help train mailbox providers
In the first weeks, engagement signals matter a lot. Encourage trusted recipients to:
✅ open your email
✅ reply (even short replies help)
✅ mark the email as Not spam if it lands in spam
✅ star / mark as important (especially helpful for Gmail)
These actions help mailbox providers learn that your emails are wanted.
Why images might not load automatically
Even if your email lands in Inbox, images may still be hidden due to:
- recipient privacy settings
- provider rules for unknown/new senders
- low sender reputation
- promotional-style email structure
This usually improves as your domain builds trust.
Improve sender reputation faster with Hostinger Reach
Warm-up is important — but you’ll get the best results by also improving email quality, list health, and domain authentication. Hostinger Reach includes features designed to help with all three.
✅ 1) Reduce spam risk with Template Checker (AI-powered)
Your email content impacts deliverability. Spelling errors, risky wording, or poor formatting can increase the chance of spam filtering.
With Hostinger Reach Template Checker, AI reviews your email and checks for:
- spam-risk content and formatting
- grammar and spelling issues
- accessibility and readability improvements
You’ll also get actionable suggestions — and can fix issues automatically with AI in one click to send a cleaner, better-performing campaign.
✅ Benefit: higher email quality → fewer spam signals → better inbox placement.
✅ 2) Keep deliverability strong with Clean Contact Lists
Sending to invalid addresses hurts your sender reputation quickly — especially when you’re new.
If your campaign includes hard bounced emails (invalid email addresses), Hostinger Reach allows you to easily remove them from your contacts so you don’t keep sending to them again in one-click.
✅ Benefit: fewer bounces → better deliverability rate → improved domain reputation.
✅ 3) Set up the correct DNS records (recommended for deliverability)
Mailbox providers expect domains to have proper authentication and deliverability-related DNS records in place.
Hostinger Reach follows best-practice guidelines and shows you whether your domain setup is complete.
To check your status:
- Go to Hostinger Reach → Domain settings
- Make sure every deliverability item is enabled
- Confirm all checkboxes are green
✅ Benefit: stronger domain authentication → better trust with Gmail/Yahoo/Outlook.
What’s coming next in Hostinger Reach
1- Send-time optimization for better open rates
We’re working on scheduled campaign delivery based on each recipient’s behavior — so emails can be sent at the time they’re most likely to open them.
✅ Benefit: higher open rates → stronger engagement signals → better deliverability.
2- Double opt-in to improve contact quality
Double opt-in helps confirm that every new subscriber email address is real and intentional.
When enabled:
- someone submits a form on your website
- Hostinger Reach sends a confirmation email automatically
- only confirmed contacts are added to your list as Subscribers
✅ Benefit: fewer fake/incorrect emails → fewer bounces and complaints → healthier sending reputation.
Quick checklist: best practices for your first weeks
✅ Warm up slowly (don’t send large campaigns immediately)
✅ Ask recipients to open/reply/mark as not spam
✅ Use Reach Template Checker feature to improve quality before sending
✅ Remove contacts who had hard-bounce emails in your campaign details page
✅ In Reach domain settings, verify you have all the correct DNS
✅ Grow volume gradually and keep engagement high