Sendersy blog
Deliverability, email marketing, transactional email and APIs — practical guides from the Sendersy team.
RSS feedEmail Deliverability: 12 Fixes to Land in the Inbox, Not Spam
A practical checklist to improve email deliverability — authentication, list hygiene, content, and reputation, in plain language.
SPF, DKIM and DMARC: The Complete Email Authentication Setup
A step-by-step guide to configuring SPF, DKIM and DMARC records so your email passes authentication at Gmail, Outlook and Yahoo.
Choosing an SMTP Relay Service: What Actually Matters
When to use an SMTP relay vs an API, what to look for, and how to migrate without breaking your existing app.
Email Marketing Automation: Build Drip Campaigns That Convert
How to design triggered email sequences — welcome series, onboarding and win-back — that run on autopilot and actually drive revenue.
How to Reduce Email Bounce Rate (and Why It Matters)
Hard vs soft bounces, what a healthy bounce rate looks like, and the exact steps to keep yours low and your reputation high.
Email Open Rates in 2026: Benchmarks and How to Improve Them
What counts as a good open rate, why Apple Mail Privacy changed the metric, and practical ways to get more people reading.
Double Opt-In: Why It Protects Your Sender Reputation
What double opt-in is, the trade-off with list growth, and why the long-term deliverability win is worth it.
How to Warm Up a New Email Domain or IP
A week-by-week warm-up schedule for new sending domains and IPs so you build reputation instead of getting blocked.
Choosing Newsletter Software: A Practical Buyer’s Guide
The features that actually matter in newsletter software — deliverability, editor, automation, pricing — and how to compare them.
Abandoned Cart Emails That Recover Revenue
How to build an abandoned cart sequence — timing, copy and number of emails — that wins back sales on autopilot.
Email List Segmentation: Send Less, Earn More
Why segmented campaigns outperform batch-and-blast, the segments worth building first, and how to keep them updated.
Why Your Emails Go to Spam (and How to Fix It)
The real reasons messages land in spam — authentication, reputation, content and engagement — and a fix for each.
Welcome Email Best Practices: The First Impression That Sticks
What to put in a welcome email, when to send it, and why it is the highest-engagement message you will ever send.
Email Subject Lines: Formulas That Actually Get Opened
Proven subject-line patterns, length guidance, and the preheader trick most senders forget — with examples.
Email API vs SMTP: Which Should Your App Use?
A clear comparison of sending email over an HTTP API versus SMTP — speed, features, reliability and when to pick each.
Email Blasts Done Right (Without Killing Your Reputation)
When a mass email makes sense, how to send one safely, and the segmentation that keeps a blast from torching deliverability.
Dedicated IP vs Shared IP for Email Sending
The trade-offs between a dedicated and a shared sending IP, and how to know which one your volume actually needs.
Email Click-Through Rate: How to Get More Clicks
What a good CTR looks like, why it beats open rate as a signal, and concrete ways to get more readers to act.
Email Blacklists: How to Check and Get Removed
What email blacklists are, how to tell if you are on one, and the steps to get delisted and stay off.
Drip Campaigns: A Beginner’s Guide to Automated Email
What a drip campaign is, the sequences worth starting with, and how to set one up without a marketing team.
Email Personalization: Beyond First-Name Tokens
Real personalization is about relevance, not just “Hi {{first_name}}”. Here is how to use data to send emails people actually want.
Email Automation Tools: What to Look For
The capabilities that separate real email automation from a glorified scheduler — triggers, branching, segments and deliverability.
Moving DMARC to p=reject Safely
A staged plan to tighten your DMARC policy from none to quarantine to reject without blocking your own legitimate email.
The Best Time to Send Email (and How to Find Yours)
Generic “best time” charts are a starting point, not an answer. Here is how to find the send time that works for your list.
Email Rate Limiting: Why Throttling Protects Deliverability
Sending too fast looks like an attack to mailbox providers. Here is how throttling and rate limits keep your mail flowing.
Email Webhooks: React to Delivered, Bounced and Opened in Real Time
What email webhooks are, the events worth subscribing to, and how to handle them reliably in your app.
GDPR and Email Marketing: Consent Done Right
A plain-language guide to collecting, recording and honoring consent for email under GDPR — without killing your list growth.
Re-Engagement Emails: Win Back Dormant Subscribers
How to build a win-back sequence that revives inactive subscribers — or cleanly removes them to protect deliverability.
HTML Email Templates: Why They Break and How to Build Ones That Don’t
Why email HTML is stuck in 2005, the table-based rules that keep templates from breaking, and how to skip the pain entirely.
Email Marketing Metrics That Actually Matter
Which email metrics to track, which to ignore, and how to tie them to revenue instead of vanity.
Cold Email Outreach Without Destroying Your Domain
How to run cold outreach responsibly — separate domains, warm-up, volume limits — so it does not torch your main sending reputation.
Integrating an Email API: A Practical Checklist
Everything to get right when you integrate an email API — keys, retries, webhooks, suppression and testing — in one checklist.
Spam Traps: What They Are and How to Avoid Them
The types of spam traps, how they end up on your list, and the list hygiene that keeps you off blacklists.
Email List Building: Grow Quality, Not Just Numbers
Ethical, effective ways to grow an email list that engages — opt-in forms, lead magnets, and why you should never buy lists.
Transactional vs Marketing Email: Keep Them Separate
The difference between transactional and marketing email, and why mixing them on one domain risks your most critical messages.
Inbox Placement: How to Measure Where Your Email Lands
Delivery rate is not inbox placement. Here is how to actually find out whether your email reaches the inbox or the spam folder.
Email Open Tracking: How the Pixel Works (and Its Limits)
How open tracking works, why privacy features broke it, and what to measure instead for an honest read on engagement.
Sender Reputation: The Score That Decides Your Inbox Fate
What sender reputation is, what drives it up or down, and how to build and protect it over time.
How an Email Sending Queue Works
Why serious email goes through a queue, how retries and backoff work, and what that means for your app.
BIMI: Get Your Logo in the Inbox
What BIMI is, what it requires (DMARC enforcement and often a VMC), and whether it is worth setting up.
Email Frequency: How Often Should You Email?
How to find the right sending frequency for your audience without burning out your list or hurting deliverability.
Keeping Your Email API Key Secure
Practical rules for storing, scoping and rotating email API keys so a leak never becomes a spam incident.
Notification Emails Users Actually Read
How to design product notification emails that are timely, scannable and useful — instead of noise people mute.
Email Marketing for E-commerce: The Flows That Drive Sales
The core automated flows every online store should run — welcome, cart, post-purchase, win-back — and how they compound.
Email A/B Testing: What to Test and How to Read Results
A practical guide to A/B testing emails — what to test, how big a sample you need, and how to avoid fooling yourself.
Email Verification: Clean Addresses Before You Send
What email verification checks, when to use it, and how it cuts bounces and protects your sender reputation.
Free Email API: What You Get and Where the Limits Are
What a free email API tier realistically includes, what to watch for, and how to know when to upgrade.
The Email Deliverability Checklist for 2026
A copy-paste checklist covering authentication, list hygiene, content and monitoring — everything to verify before you send.
Email Preference Centers: Reduce Unsubscribes the Smart Way
Why a preference center beats a single unsubscribe button, what to include, and how it protects your list and reputation.