30 deliverability tips

How to increase your email deliverability rate – 30 insider tips

Now that you have a clear picture of the basis on which your emails are judged, you can see that there are ways in which you can influence this judging process, to maximise your deliverability rate.

Here, we give you 30 practical steps to maximise your email deliverability.



  • Ensure the domain you use for sending emails is configured to enable authentication (SPF/Sender ID/DomainKeys).
  • Sending your emails at a steady rate, from a dedicated and consistent IP address will help to build your reputation with the ISP's.

    This will also ensure you avoid the threat of an ISP blacklist impacting your day to day emails sent from your business domain.
  • Ensure your messages are sent from a meaningful ‘friendly’ from address in the message header – NOT from a string of numbers
  • Display a privacy policy opt-in statement, and declare your identity and how you intend to use an email address at the time of collecting it.
  • Do not email to contacts who have not given you prior permission to email them your marketing messages. (There are legitimate exclusions to this rule - refer to the DMA Direct Marketing Code of Practice for further information.).
  • Gain permission to email contacts, by providing a positive ‘Opt-in’ box for them to check.
  • Confirm email address validity and your permission to email, by sending a ‘non-commercial welcome email’ to all new contacts.
  • Use the welcome email to invite new contacts to add you to their ‘Safe/Trusted Senders’ list within their inbox or to add you to their address book.
  • Consider using a ‘double opt-in’ for new contacts. Here, your welcome email will require the contact to click through and confirm their details and consent.

    Double opt-in has pros and cons.  It may build you a database of highly engaged and responsive contacts.

    But it may also increase the chance of drop-out and limit the size of your database.
  • Ensure opt-ins are collected offline (i.e. via call centre, customer care, sales team, registration cards) with new contacts captured via these channels.
  • Ensure email addresses collected offline are emailed and validated (i.e. not hard-bounced back) before they are added to your main contact database.
  • Always provide a highly visible unsubscribe link in all your email message.
  • Ensure your unsubscribe link requires no more than 2 clicks on the part of the unsubscriber.
  • Ensure your unsubscribe page is branded with your company name, logo etc, to instil trust in unsubscribers and encourage them to use this channel for unsubscribing, rather than clicking the ‘Junk’ button in their inbox.
  • Ensure your Unsubscribe Link processes unsubscribe requests in real-time.
  • Ensure offline points of contact are available for unsubscribers (e.g. a phone number and postal address) and that these requests are processed in a reasonable time frame.
  • Make sure you keep your lists clean by deleting all hard bounces (hard bounces are undeliverable emails due to a permanent error).
  • Handle soft bounces (these are undeliverable emails due to a temporary error such as a full inbox or an Out of Office reply). Depending on your frequency of send, 3 consecutive soft bounces could be enough to classify a contact as a hard bounce.
  • Treat your email database like you would treat your mailing database – keep it clean, up-to-date, deduped, and free of gone-aways.

    Flag ‘dead’ contacts and long-term inactive recipients who never respond, test email them to see if they can be reactivated, and if not then stop emailing them.
  • Identify from your email database who the key ISPs for your campaigns are, and establish a relationship with them.
  • Contact them to introduce yourself, explain your opt-in policy and ask for advice on how to avoid their black list.
  • If you receive a bounce back with a black list message, always contact the ISP and get a named contact to speak to about the black listing.
  • Have a copy of the bounced message to send them and be ready to explain your privacy and opt-in policies and to ask for advice on how to avoid their black list.
  • Consider subscribing to a Delivery Monitoring Solution that will provide continuous monitoring of your reputation and black list status and provide snapshots of your authentication levels.
  • Email Service Providers (ESPs) provide this service by default.
  • Consider using an Email Service Provider (ESP). Sending your emails via an ESP such as dotmailer.co.uk means you can benefit from their acquired reputation, white listings, accreditation and ISP relationships, built up over many years and over large volumes of legitimate email marketing. This level of reputation is priceless.
  • Choose an ESP that is signed up to ‘Feedback Loops’ on the major ISPs such as Hotmail. AOL and Yahoo. A ‘Feedback Loop’ allows the ISP to send an unsubscribe mail to your database when a recipient of your email hits the ‘Report Spam’ button. This enables you to unsubscribe/suppress the complaining recipient from future sends, avoiding repeat complaints and protecting your reputation.
  • Double-check that your email content isn’t being caught by spam content filters at the last hurdle, by using a spam checker to analyse and score your templates.
  • Use an ‘Inbox Preview’ or ‘Email Proofing’ tool to check how your email templates render in different ISP's inboxes - particularly where images are turned off. Spam checking and email proofing tools are offered by email marketing provider dotmailer.co.uk
  • Avoid large graphics, or a high proportion of graphics to plain English text, that can be scanned by a spam content filter.

For more detailed information regarding email deliverability, refer to read the Direct Marketing Association's whitepaper 'Email Deliverability: How We Got Here and What Marketers Should do About It' - co-authored by dotMailer Director, Tink Taylor.

Get started with dotMailer:

Small & Medium businesses Large businesses
Call the team on 0845 337 9170
What our clients say:

“dotMailer has changed our complete marketing process for the better. It's one of the easiest apps I have used and allows us to do things we have only dreamed of before."

Amberley Shermon, Cazenove+Loyd