Sending email best practices

Effective email communication is essential for engaging customers. This article covers best practices for writing and sending outbound emails — from personalisation through to design, testing, and compliance — to help you maintain a healthy sender profile.

1. Setting up

Before you start sending, make sure your Sender Profiles are set up correctly.

Use a subdomain to protect your domain reputation

Using a subdomain isolates your email sending reputation from your primary domain. This means any deliverability issues — such as high bounce rates or spam complaints — only affect the subdomain, not your main domain or website.

For example, you can set up sender profiles to send from:

• marketing.example.com for marketing emails
• orders.example.com for transactional emails

This keeps your marketing and transactional sending separate, protecting critical emails like password resets and order confirmations from being impacted by marketing performance.

Stay compliant

Staying compliant protects your sender reputation and ensures your emails continue to reach recipients.

• Maintain clean recipient data and process unsubscribe requests immediately to keep spam complaint rates low and maintain a healthy sender profile status.
• Include a clear, visible unsubscribe link in every marketing email
• Ensure the "From" and "Reply-To" addresses are accurate and not misleading

2. Write your email

Subject lines

• Keep them concise and action-oriented to encourage opens.
• Avoid using all caps or excessive punctuation, which can trigger spam filters.

Content structure

• Focus on delivering one main message or call to action per email.
• Use short paragraphs, bullet points, and clear headings to make the content easy to scan and understand.

3. Personalise your email

Merge fields

Merge fields enables dynamic personalisation, making messages feel more relevant to each recipient. They automatically insert specific data from your system of record or a previous node into your email templates, such as names, appointment details, or invoice number.

For more details, see Working with merge fields and Designing emails with Outbound Email node.

4. Build your email

There are two primary methods for designing emails within the Outbound Email Node: Build from scratch or use HTML code. While custom HTML offers flexibility, it may cause visual discrepancies across different email clients.

To ensure visual consistency, we recommend using the drag and drop builder (Build from scratch option).

For more details, see Outbound Email Node and Designing emails with Outbound Email node.

5. Test and optimise

A/B testing

A/B testing lets you compare different versions of an email to see which performs better. In Pendula, you can use the Criteria Filter to split your audience into groups and send each a different version.

For example, a flow triggered by a form submission can use a Criteria Filter to divide recipients into two groups — customers who meet the criteria are placed in Group A and receive Email A; everyone else receives Email B. By comparing results across both groups, you can identify which email drives better open rates or conversions.

For a detailed guide, see Criteria Filter and Criteria Split

Track deliverability with outcome paths

The outbound email node provides two outcomes paths:

• “Sent” path - Successfully submitted to the provider for delivery.
• “Not sent” path - Could not submit message to provider.

Use these paths to:

• Update your records – Use the outcome and outcome reason merge fields to notify an agent or sync delivery status to your system of record.
• Send via an alternate channel – Route undelivered messages through SMS or another channel.
• Remove problematic addresses - automatically remove addresses that repeatedly fail. Repeated failures such as hard bounces will negatively affect your sender profile health.
• Monitor email performance – track jet events including clicks, opens, deliveries and hard bounces.
• Sync events to another system – Use Activity Sync to push email events to your system of record. Learn more

For more details, see Outbound Email Node