EmailFlow OS
Playbooks on personalised video, cold email and B2B prospecting — written for the people who actually send the campaigns.
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10 min read
An email ending has three parts, in this order. First, a closing line that states one next step ("Does Thursday morning work?"). Second, a sign-off that fits how well you know the reader. For business mail that's "Best", "Thanks" or "Kind regards". Third, a …
Read the article8 min read
Brevo bills by emails sent, Mailchimp by contacts stored. How each signs your domain with DKIM, and which suits B2B outreach from your own domain.
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A video sales letter runs hook, problem, mechanism, proof, offer, ask. How to script one, where to host it, and why email links to it, not embeds it.
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SaaS sales sells subscriptions, so the deal continues after signature. Three sales models, tools by job, follow-up templates and DNS checks to run first.
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Email verification runs a syntax check, an MX lookup and an SMTP RCPT TO probe. What valid, catch-all and unknown mean, and why greylisting skews results.
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An email spam test sends a real message to a tester address or seed inboxes, then reads SPF, DKIM, DMARC, content rules and blocklists. Steps and limits.
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A sales cadence is a dated plan of touches across email, phone and LinkedIn, plus exit rules. Example schedule, follow-up templates and failure modes.
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CAN-SPAM Act requirements per the FTC: truthful headers and subject lines, a postal address, an opt-out honoured within 10 business days, no B2B exception.
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An SMTP relay takes authenticated mail and hands it to the recipient's server. Covers Google's smtp-relay.gmail.com, Amazon SES, free tiers, DKIM alignment.
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Video voicemail is a recorded clip emailed after a missed call. How to make one, why it won't play inline, and why Gmail turns big attachments into Drive links.
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Spam trigger words add points in rule-based filters like SpamAssassin, while Gmail weighs domain reputation and complaints more. Lists, subject lines and tests.
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Sender Score is Validity's reputation rating for a sending IP. Find your Brevo IP in the Received header, look it up, and see why a shared IP's score misleads.
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Cold email tips: authenticate your domain with SPF, DKIM and DMARC, write one ask per email, thread follow-ups via In-Reply-To, and know when to stop.
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Cold email vs cold call compared on timing, reach, scale and legal rules (US TSR, CAN-SPAM, German UWG), plus follow-up templates that connect the two.
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An email sequence is a series of timed emails that stops on a reply. Cold outreach steps, threaded follow-up templates, stop rules and DNS checks to run first.
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LinkedIn outreach tools by type, why LinkedIn's User Agreement bars bots, connection-note templates, and how to add an email step from your own domain.
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Gmail sending limits are per user over a rolling day, and To, Cc and Bcc all count. Google bounces mail past the quota. Plus Gmail's SPF and DKIM records.
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Check a subject line in four passes: an analyzer for wording, a test send to Gmail and Outlook, the auth headers, then MX and SPF lookups with dig or Check MX.
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Funny sales email examples for openers, follow-ups and breakups, why GIFs and a fake "Re:" hurt deliverability, and when humour in B2B outreach misfires.
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Add a GIF in email through Gmail's Inline option, Outlook's Insert > Pictures or an img tag. Why some Outlook versions freeze it and base64 GIFs break.
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Gmail read receipts need a Workspace account and an admin to enable them. Where the setting sits, why receipts fail, and Gmail's SPF and DKIM records.
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DMARC reports are XML files listing source_ip, count, disposition and aligned SPF/DKIM per row. How to read each field, sort senders and know what to fix.
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Email list hygiene for cold senders: drop hard bounces before any follow-up, treat catch-all results as unknown, and re-verify a list before each import.
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An email blacklist is a DNS list that receiving servers query per IP or domain. How to check with dig, why Spamhaus rejects public resolvers, and how to delist.
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A breakup email ends a sequence: reply in-thread, offer one-word answers, then stop. The FTC's CAN-SPAM guide: honour opt-outs within 10 business days.
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Email reputation check in order: authentication headers, Google Postmaster domain data, blocklists, then bounces. Why IP checks mislead on a shared Brevo IP.
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A catch-all email accepts mail for any address at a domain. Where Workspace, Proton and cPanel hide the setting, and why verifiers mark such addresses unknown.
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Read spf=, dkim= and dmarc= in the Authentication-Results header and Outlook's SCL spam score, then fix misaligned DKIM, bounced addresses and volume spikes.
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Email deliverability tools by job: MxToolbox for DNS and blocklists, GlockApps for seed tests, Kickbox for list checks, Postmaster Tools for Gmail data.
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Prospecting means finding, researching and qualifying potential buyers before first contact. Lead vs prospect, the 7 sales stages, and where outreach breaks.
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Gmail caps personal attachments at 25 MB and turns bigger files into Drive links. Three ways to send a video by email, and why inline playback rarely works.
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Cold email marketing setup choices: whose domain signs DKIM, where the list lives, In-Reply-To threading, CAN-SPAM opt-out rules and follow-up templates.
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Prospecting email examples by trigger, three threaded sales follow-ups, why a fake Re: subject backfires, and how EU consent rules differ from US opt-out.
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Email personalization in four levels: merge tags, segments, per-recipient lines and video. Fallbacks for empty fields, tool options and EU data rules.
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B2B email marketing covers opt-in programs and cold outbound. How to pick a tool for each, whose domain signs DKIM, and Germany's UWG consent rule.
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Email follow up apps sorted by job: Apple Mail's reminder, Gmail add-ons, sequence tools. Plus In-Reply-To threading and why follow-ups count toward volume.
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Follow up email after no response: check bounces first, reply in-thread via In-Reply-To headers, use copy-ready sales templates, and know when to stop.
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Follow up email after a sales call: recap within 24 hours, one dated next step, a real reply in the thread via In-Reply-To, and templates by call outcome.
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B2B lead generation sorted by job: contact data, enrichment, CRM and sending tools, what an agency controls, and whose domain should sign your outreach.
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How to write a follow-up email: a five-part structure, timing by situation, polite update phrases, sales templates, and why a fake "Re:" never threads.
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DMARC setup in four steps: SPF and DKIM aligned first, one TXT at _dmarc with p=none and rua, read the XML reports, then move to quarantine.
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Cold email deliverability is decided by the receiving server: SPF, DKIM and DMARC alignment, domain reputation, bounces, complaints and volume per mailbox.
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How many cold emails per day: 30–50 per warmed mailbox, 100 at most, 10–20 while warming (as of Oct 2026), plus why follow-ups count toward the cap.
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Email deliverability checklist for cold senders: DMARC alignment with your From domain, hard-bounce removal, warm-up order and EU consent checks.
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Delivery rate = accepted ÷ sent; inbox placement is separate. Vendor benchmarks run 85–99%, plus why accepted mail lands in spam and how to fix it.
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Sender reputation is two scores: IP and domain. Which you can check in Google Postmaster Tools, Spamhaus or Sender Score, and what to fix first.
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Best time to send cold emails: Tuesday to Thursday mornings in the recipient's time zone, why opens can't prove it, and when 8 AM or 7 PM sends make sense.
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Cold email automation explained: what software automates, SPF/DKIM/DMARC before sending, named tools by job, follow-up templates and Germany's UWG §7 rule.
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Cold email tool options sorted by job: Apollo.io, Clay, Smartlead, Saleshandy, Reply.io. Plus the DNS records to publish first and three follow-up templates.
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Sales prospecting tools sorted by job: contact data, LinkedIn search, enrichment, CRM and sending, plus how to check which domain signs DKIM.
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Cold email software checklist: DKIM signed by your own domain, one-click unsubscribe headers, where the list lives, and what small B2B agencies use.
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Sales outreach examples for first touch and follow-ups, a five-part reusable template, and how video outreach goes out from your own Brevo account and domain.
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Cold email subject line examples for first touch, video emails and follow-ups, why a fake "Re:" never threads, and which subject lines draw spam reports.
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Copy-ready follow up email subject lines by situation, why a fake "Re:" misstates the message, and how In-Reply-To headers keep a follow-up threaded.
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Email bounces for cold senders: how to read Action, Status and Diagnostic-Code in a bounce notice, user unknown vs. deferral, and when to stop a follow-up.
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Copy-ready email outreach openers and threaded follow-ups, the SPF, DKIM and DMARC records your own domain needs, and the causes behind spam-folder sends.
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Google Workspace DMARC: one TXT record at _dmarc, p=none first, SPF and DKIM passing beforehand, and why two v=DMARC1 records count as no policy at all.
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Google Workspace DNS records: the smtp.google.com MX, one combined SPF record, the google._domainkey DKIM key you must activate, and DMARC at _dmarc.
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Email open rate = unique opens ÷ delivered. Why Apple Mail Privacy Protection inflates it, Outlook deflates it, and what cold senders should track instead.
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Cold email meaning: a one-to-one message to someone with no prior contact. Covers German UWG consent, CAN-SPAM opt-out, email headers and SPF, DKIM, DMARC.
Read12 min read
Sales follow up email templates: a same-day recap after a sales call, no-reply and breakup emails, In-Reply-To threading and why silence isn't consent.
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Choosing a video messaging tool for cold email: whose domain signs DKIM, where the prospect list lives, and the Authentication-Results check before launch.
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A personalized video message per recipient, not per company: why Gmail and Outlook don't play video inline, and how DMARC checks your own sending domain.
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SPF checks the sending server, DKIM signs the message, DMARC demands alignment with From. Setup order, failure causes and Workspace plus Brevo records.
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Sample cold email templates for first contact, video intros and follow-ups, plus Germany's B2B consent rule and the authentication Gmail checks.
Read11 min read
G Suite DKIM setup: generate the key, publish the google._domainkey TXT, click Start authentication, then add the separate DKIM record Brevo shows you.
Read9 min read
Cold email format in six parts, the headers it needs (From, Message-ID, List-Unsubscribe), why to send plain text plus HTML, and where video fits.
Read7 min read
GoDaddy DKIM for Brevo: why the Host field doubles your domain, why edits fail on outside nameservers, and how to check the selector with dig.
Read12 min read
When to send a cold email follow up, how In-Reply-To and References headers keep it threaded, one-click unsubscribe, and the signals that mean stop.
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Copy-ready sales email subject lines for cold emails and follow-ups, plus the CAN-SPAM rule on misleading subjects and Gmail's 0.3% spam-rate limit.
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Cold outreach from one recorded video, sent through your own Brevo account: SPF merge rules, DMARC p=none first, and the list errors that hurt your domain.
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Email warm up for cold outreach: a week-by-week volume ramp, SPF, DKIM and DMARC before day one, and the failure modes that stall a new sending domain.
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Video prospecting: one recording, one version per recipient, sent through your own Brevo account and domain. Covers SPF, DKIM, DMARC p=none and list hygiene.
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Video email: why attached files fail, why Gmail and Outlook skip embedded video, and how one recording becomes a version per recipient via your Brevo.
ReadThe guides on this blog come from the team that builds EmailFlow OS. They are written for people who run cold outreach from their own Brevo account and their own sending domain and want to keep both in good standing. Each guide takes one question and answers it with the record names, thresholds and standards we work with, and it says where a step tends to go wrong.
The articles cover three areas: a sending domain that mailbox providers trust, cold emails and follow-ups that people can answer, and personalized video that does not put either of the first two at risk.
Mailbox providers check every message for SPF, DKIM and DMARC. If a record is missing or does not match the domain in the From address, a carefully written email can still land in spam or be rejected. The setup guides go into the details where this usually breaks.
For Google Workspace, our guide to G Suite DKIM shows where the TXT record under google._domainkey goes, how a 2048-bit key is split into strings of 255 characters and why mail sent through Brevo needs its own key. If your DNS is hosted at GoDaddy, the GoDaddy DKIM setup for Brevo senders explains why the Host field doubles your domain name, why edits have no effect on outside nameservers and how to check the selector with dig.
A new domain also needs a sending history before it carries volume. Our article on email warm-up explains why volume should grow gradually and what it means for your reputation when the sending domain is yours.
The cold email format guide breaks a cold email into six parts, lists the RFC 5322 headers it needs, compares plain text with HTML, shows why Gmail clips a message once its HTML passes about 102 KB and explains what GDPR Article 14 asks of a cold email. Our collection of sales email subject lines has wording for first emails and follow-ups, together with the CAN-SPAM rule against misleading subjects.
When a prospect does not reply, the guide to the cold email follow up covers timing, how threading works under RFC 5322, what Google requires from senders of 5,000 or more messages a day, the one-click unsubscribe defined in RFC 8058 and when to stop.
EmailFlow OS starts from a single recording. You upload one video, connect your Brevo account and sending domain and import your prospect list, which then lives in EmailFlow OS. Every recipient gets a personalized version of their own, not one per company, and each version leaves from your own inbox through your Brevo account, never through a shared platform sender.
The guide to video prospecting with one recording walks through that workflow step by step, including the SPF, DKIM and DMARC records to set up before the first send and the EU consent rules that apply. Video email for B2B outreach explains the mechanics: why attaching the file rarely works when Gmail caps attachments at 25 MB, and why an embedded video does not play in Gmail or most versions of Outlook. Cold outreach with EmailFlow OS shows how a campaign is set up from start to finish.
Each guide names the standard or provider rule behind a step, for example RFC 5322 for threading, RFC 8058 for one-click unsubscribe or Google's requirements for bulk senders, so you can check it yourself. We do not promise open or reply rates. No tool can guarantee inbox placement, and the guides say so where it matters.
EmailFlow OS