SMTP & email deliverability for home services

Texts handle the fast, short stuff. Email still carries the things that close jobs: the confirmation with the full appointment details, the branded estimate, the "just following up on your quote" nudge. If those land in spam, you lose deals and never know it. Deliverability is the fix, and most of it comes down to a few DNS records.

SMTP in one minute

SMTP (Simple Mail Transfer Protocol) is the standard for sending email, the engine behind every "send." When your CRM sends an estimate, it hands the message to an SMTP server, which relays it to the recipient's mail provider. The question that provider asks before showing it to your customer is simple: can this sender prove it's really allowed to send as this domain? Three records answer that.

Authenticate the emails that carry your quotes

SPF, who's allowed to send

SPF (Sender Policy Framework) is a DNS record listing which servers may send email for your domain. When a message arrives claiming to be from you@yourcompany.com, the receiver checks your SPF record to see if the sending server is on the approved list. No SPF, or a server that isn't listed, is a red flag.

v=spf1 include:_spf.google.com include:sendgrid.net ~all

DKIM, proof it wasn't tampered with

DKIM (DomainKeys Identified Mail) adds a cryptographic signature to each message. Your sending service signs with a private key; the receiver checks it against a public key in your DNS. A valid signature lets the recipient verify the signing domain and check whether the signed content changed in transit.

DMARC, what to do when checks fail

DMARC (Domain-based Message Authentication, Reporting & Conformance) ties SPF and DKIM together and tells receivers how to handle mail that fails: do nothing, quarantine (spam folder), or reject. It also emails you reports on who's sending as your domain.

v=DMARC1; p=quarantine; rua=mailto:dmarc@yourcompany.com

As of 2024, Gmail and Yahoo require SPF, DKIM, and DMARC for anyone sending at volume. This isn't best-practice-nice-to-have anymore; it's the entry ticket.

Setting it up

1. Send from your own domain, not a free address. bookings@yourcompany.com builds trust; yourcompany@gmail.com can't be authenticated and looks off to customers.
2. Add the SPF record your sending service gives you. If you send through more than one service, combine them into a single SPF record (you're only allowed one).
3. Turn on DKIM in your email/CRM platform and paste the DKIM DNS records it generates.
4. Publish a DMARC record. Start with p=none to monitor, read the reports, then tighten to p=quarantine once legitimate mail passes.
5. Warm up gradually. Don't blast a cold list from a brand-new domain. Ramp volume over days so providers learn you're legitimate.

How to tell if it's working

• Send a test to a Gmail address, open it, and check "Show original", SPF, DKIM, and DMARC should all read PASS.
• Run your domain through a free authentication checker (MXToolbox, Google's tools) and fix anything flagged.
• Watch your DMARC reports for unexpected senders, that's either a misconfiguration or someone spoofing you.

Get this right alongside your A2P 10DLC setup and both halves of your follow-up, text and email, actually reach the customer. That's the quiet infrastructure behind a system that books jobs.