Microsoft 365 or Google Workspace Down? How to Keep Business Email Working During an Outage
When Microsoft 365 or Google Workspace goes down, email stops. How to keep receiving and replying during an outage with a gateway you control.
6 AI Prompts That Check Your Email Deliverability and Explain the Results
Six copy-paste prompts for ChatGPT, Claude or Grok that run live email checks through a free MCP server: domain health, spam test, links, new domains and BIMI.
How to Build an AI Prospecting Email Agent That Finds Leads and Emails Them Safely
Build an AI prospecting agent that researches companies, drafts relevant first emails and sends only through a send gate it cannot bypass. Free open-source code.
Building an AI Agent That Sends Email? Treat It Like a Bulk Sender
An AI agent that emails people is a sender like any other, and the Gmail and Microsoft rules apply from the first message. An eight-step checklist for builders: domains, a send gate, one suppression list, one-click unsubscribe, caps, reply handling, honest identity and monitoring.
How to Run a Spam Test or Email Deliverability Audit from ChatGPT, Claude & Grok - 8 Real Examples
Connect one MCP server and run real email checks from ChatGPT, Claude or Grok: blacklists, spoofing, redirect traces, spam tests, WHOIS - with 8 real examples.
Brand Impersonation in Email: The Four Attacks, and What Actually Stops Each One
The four email brand-impersonation attacks - display-name, trusted-brand lures, DKIM replay and exact-domain spoofing - shown with real headers and the defense that stops each.
How to Use Google Postmaster Tools (v2): Setup, Access and Every Dashboard Explained
A complete, practical guide to Google Postmaster Tools: what it is, why the reputation dashboards were retired, how to add and verify a domain, delegate access, and read every dashboard - Compliance status, Spam, Feedback Loop, Authentication, Encryption and Delivery Error.
Gmail Spam Rate Above 0.3% in Postmaster Tools? Here's How to Fix It
Your Gmail Postmaster Tools spam rate is above 0.3% and delivery is slipping. Here's what the threshold means, how to diagnose the cause, and a realistic timeline to recover.
SMTP Error Codes Explained: 4xx and 5xx Bounce Codes and How to Fix Them
Decode SMTP error codes: what 421, 450, 550, 552 and 554 mean, plus the Gmail, Outlook, Yahoo, Zoho and iCloud bounce codes - and how to fix each one.
What is APRF? Aggregate Performance Reporting, Explained Simply
What is APRF? A new email standard that emails senders inbox-placement and engagement reports - like Google Postmaster Tools, but from any mailbox provider.
How to run a free spam test (email deliverability audit)?
Run a free email spam test in 2 minutes: send one email, get a deliverability score out of 10, and see exactly what to fix first. No signup - step by step.
Email Spam Testing Tools Compared: mail-tester, Unspam, MailChecker and Postbox Mailtester (2026)
An honest 2026 comparison of four free email spam testing tools - mail-tester, Unspam, MailChecker and Postbox Mailtester. What each checks, where each stops, and which to reach for when.
BIMI Setup Guide: How to Add Your Brand Logo to Emails
Set up BIMI step by step - the DNS record, the SVG logo rules, VMC vs CMC certificates, and what Gmail, Yahoo and Apple Mail require in 2026 - plus how to get BIMI implemented if you would rather work with a consultant in India.
Microsoft Email Deliverability: The Complete Debugging Guide (2026)
The complete 2026 guide to Microsoft email deliverability: 15 bounce codes decoded, compauth/SCL headers from real captures, SNDS, escalation paths, and fixes per sender type.
Real vs Bot Opens and Clicks: Spot Fake Email Engagement
Security scanners and privacy proxies inflate your open and click rates. How to tell real from bot opens and clicks, and measure genuine human engagement.
DKIM Replay: Why a Valid Signature Doesn't Prove the Sender
A DKIM replay attack re-sends one validly signed message to millions and it still passes. How replay works, a safe lab to see it, and how DKIM2 fixes it.
What Is a DMARC Aggregate Report? (And How to Actually Read One)
A provider dropped an unreadable XML file in your inbox? Here is what a DMARC aggregate report is and how to read one, field by field, with a worked example.
How to Read Email Headers to Spot Phishing and Spoofing
Anyone can fake a sender name - the email headers are the receipts. Learn to read Authentication-Results and the Received chain to catch a spoof in seconds.
What Is TLS-RPT? How to Set Up MTA-STS Safely (Step by Step)
TLS-RPT tells you when senders cannot reach your mail server securely. Learn how it works, what the reports mean, and the safe order to set up MTA-STS without breaking your email.
Email Domain Health Check: 8 Checks Every Domain Needs
Run a free email domain health check and understand every result. MX, SPF, DKIM, DMARC, MTA-STS, TLS-RPT, BIMI and DNSSEC explained simply, with the...
Google Postmaster Tools: Plain-Language Verdicts
Google Postmaster Tools now shows plain-English verdicts like "users don't want your email." See all 7 reasons, real screenshots, and what they mean.
6 Strategies to Control Your Spam Complaint Rates
If you're struggling with low open rates it's time to look 6 Strategies to Control Your Spam Complaint Rates
Do Email Warmup Tools Work in 2025?
Are email warmup tools still effective in 2025? We tested all major providers and found most show no real improvement in deliverability or domain...
Deliverability Interviews - Radek Kaczyński from Bouncer
Bouncer is an easy to use and easy to integrate email verification solution.. Read our deliverability interview with Radek from Bouncer.
Deliverability Interviews - Sebastian Kluth from Certified Senders Alliance
In interview 5 of the deliverability interview series we spoke to Sebastian Kluth from Certified Senders Alliance.
Deliverability Interviews - Anders Berggren from Halon
Interview with Anders Berggren about Halon - a large scale MTA, its features and how it helps with email deliverability.
Deliverability Interviews - Damien Brenelière from Mailreach
Read this interview to understand how a good domain warmup tool like Mailreach can help you achieve email deliverability
Deliverability Interviews - Arun Kumar from Zoho
Interview with Arun Kumar from Zoho Campaigns team. Arun talks about various aspects of email deliverability and how Zoho has implemented these practices.
Deliverability Interviews - Przemysław Kuciel from Omnisend
Interview with Przemysław Kuciel from Omnisend about different email deliverability challenges and best practices.
Interview: Ajay Goel, Founder of GMass on the secrets of cold emails and the journey of GMass
Interview of Ajay Goel, founder of GMass on secrets of cold emails and the journey of GMass.
Interview: Vaibhav Namburi, Founder of SmartWriter on email deliverability with personalisation
An exclusive interview of Vaibhav Namburi on how Smartwriter came in to being and how it is helping people achieving deliverability.
Smartwriter Review: Improve cold emails deliverability with AI based personalisation
Smartwriter is a personalisation outreach tool that helps to improve email deliverability - read this Smartwriter review.
GlockApps Review: Inbox Placement and Spam Score Testing Tool
GlockApps is a Swiss army knife for every email marketer to run an inbox placement test with a well covered seed list.
What is an email deliverability audit
At Postbox Consultancy Services we conduct a through email deliverability audit covering every minute aspect of your emailing
Best practices for designing an email newsletter template
This blog post discusses the best practices to design a good looking and highly engaging email newsletter template.
Getting low open rates on your email? Resolve your email marketing problems
Why do you get low open rates on your email marketing campaigns? This blog hast steps to improve your email campaigns open rates
Plain text vs HTML Emails | Which one should I use?
Plain text vs HTML emails. Let's dive in to the details and see which one should be used in which scenario.
How To Land In Gmail's Primary Tab
Recipients check the Gmail's promotions tab with less interest. How to land in gmail inbox's primary tab. Let's find out.
What is Cold email | 15 Pro Tips To Write Cold Emails
A cold email is an email you send to someone who is a business prospect but stranger to you. Here are 15 pro tips to write cold emails.
What is an email deliverability manager and why do you need one
Do you know the significance of an email deliverability manager or email deliverability agency? Read this blog to find why you might need one
Anatomy of Email List Cleaning | A Complete What,Why, How and Where
Do you know what is email list cleaning or email list hygiene? Read this anatomy of email list cleaning | A complete what, why, how and where
Email Deliverability Checklist To Ensure Inbox Placement Of Your Emails
Postbox Services has developed this email deliverability checklist after studying and researching all email deliverability best practices
Email and deliverability practices to avoid during the holiday rush
Holiday season is a rush for email marketers and this rush leads to many mistakes. Let's learn how to avoid these email marketing mistakes.
Parsedmarc - Open source DMARC report analyzer and visualizer
Let's learn about ParseDMARC. An open source DMARC analyzer - alternative to commercial DMARC report processing tools.
How to Start Preparing for Black Friday Email Marketing
Black Friday and Cyber Monday email marketing preparation. Let's learn about all best practices to follow to get best email deliverability.
Feedbackloop - what is it and how to signup ?
What is a feedback loop and why should you be signing it up while setting up your bulk emailing system. Let's dive in to details.
What is an SPF record?
An SPF (Sender Policy Framework) record is used to indicate which hosts are authorised to send emails for a domain. It is defined in RFC 4408 and...
What is a DMARC record ?
DMARC stands for “Domain-based Message Authentication, Reporting & Conformance.”  DMARC is built upon two other authentication protocols: SPF (Sender...