Email Basics:: Subject Line Generator – Emarsys

This feature is currently on Pilot release for a limited number of clients only. If you are interested in participating in the Pilot phase, please speak to your Client Success Manager.

The Subject Line Generator enables you to engage our AI assistant to generate contextually relevant subject line variations based on the content of your email campaign within the Visual Content Editor (VCE). You can also use it to fine-tune your existing subject line with further variations.

When using the Subject Line Generator, please note that it is a generative AI product that stores and uses the following data:

Usage data for measurement, analysis and troubleshooting,
Prompts and baseline instructions for measurement, analysis and troubleshooting,
Your feedback (i.e. when you click the Like This Variant or Dislike This Variant icon next to a variant) to understand our users' preferences with regards to the subject line suggestions. This data is currently used for measuring user satisfaction. In the future, we may use this data to fine tune future subject lines.

For more information on the Subject Line Generator, watch the August 2024 Product Release video:

You can access the Subject Line Generator by clicking the icon on the Email Basics tab at the Content Creation step of the block-based email campaign creation workflow.

How does the Subject Line Generator work?

Based on the content of your email campaign simply prompt the tool to generate a subject line. It first starts with analyzing your email content and gathers data, for example, keywords and contextual information to understand the purpose of the email.

After completing the analysis, the assistant prompts the underlying large language model to generate the given number of subject line variations in a compatible format.

You can adapt the AI-generated subject line ideas according to its tone and language. The recommended subject lines can be further calibrated. You can ask the tool to add emojis, or personalization (in the form of tokens) to the subject line and you can suggest wording improvements as well.

Token usage rate limits

In Large Language Models (LLMs), tokens are the smallest units of text, such as words or subwords, that the model uses to process and generate language. Tokenization allows LLMs to efficiently handle complex language structures by breaking down text into these manageable components, facilitating better understanding and generation of human-like text.

Global Rate Limit (Total Usage Across all Customers and Apps) - A maximum of 5 million tokens can be processed globally across all customers and applications (SLG or Preheader) within the last 24-hour period.

Customer-Level Rate Limit - Each customer account is limited to 1 million tokens processed in the last 24 hours, regardless of what application it came from.

Customer-Application Level Rate Limit - Any individual application (SLG or Preheader) within a customer account is limited to 500,000 tokens in the last 24 hours.

Use cases

You can prompt the AI assistant to generate new subject lines based on the email campaign’s content.
You can provide specific prompts to guide the AI assistant's output, such as generating urgency or avoiding certain words.
Add emojis, personalization, and suggest wording improvements to existing subject lines.

Prompt Settings

To open the Prompt Settings, click the icon. Here you can adjust the following:

Locale - (Optional) AI can recognize the input language and also analyze the campaign language. Optionally, you can set the language to ensure subject lines are generated in the desired language.
Number of Variants - Here you can set how many variants the Subject Line Generator should create.
Creativity Scale - A higher creativity value typically makes the variants more diverse and creative but might also increase their likelihood of straying from the provided context.
Baseline Instructions - Here you can provide instructions that will be applied automatically to the subject line variants additionally to your prompt (e.g. adding emojis or personalization tokens to your subject line).

Generating AI-driven subject lines

Please consider that AI takes the email content (i.e. text version of the email, including links and alternative texts) into account when generating a subject line. To achieve ideal results, we recommend preparing the email content before generating a subject line.

If you need to generate the subject line before the email content is ready, then you can get better results by typing prompts related to the future content of the email. Even an empty email contains pieces of information that can be used when creating an AI-generated subject line. For example:

The name of your brand,
Your field or industry contained in the email header or footer,
Product selection information of your brand based on the navigation used in the email.

Go to the Content Creation > Email Basics tab and click the Subject Line Generator icon.

Scroll down to check the subject line variants.

If you hover over a variant, then you can choose from the following options:

Insert Subject Line - To insert the variant into the subject line, click this icon.
Create Variants - To generate more variants based on the selected one, click this icon.
Like This Variant - If the selected variant suits your preferences, click this icon.
Dislike This Variant - If the selected variant does not suit your preferences, click this icon.