What Are Custom Variables? (& How To Use Them In Your Cold Emails)

Updated June 2024

Custom variables allow you to add personalization to your cold emails at scale.

However, if used incorrectly, they can decrease your response rate.

In this article, I explain what custom variables are, and I will show you how to use them correctly:

- What are custom variables?
- What is an example of a custom variable?
- How to use custom variables in your cold emails
- Common mistakes

What are custom variables?

Custom variables are short pieces of text surrounded by brackets that you can add to your cold emails to dynamically enter information about your leads.

screenshot showing first name custom variable in an email

The reason why this is important is because if you are sending the same email to more than one person, then you need to use custom variables to make each email look personalized.

If you use static text, then you would need to manually send each person a new email if you wanted to add personalization.

But with custom variables, you can click “send” just one time, and it will automatically update each email so that the first name (for example) matches the lead that is being emailed.

For example, if you send the same email to 1,000 leads, and you use the {first_name} custom variable, then each lead will see their first name in the email. You could start your email as follows: “Hey {first_name}” or “Hi {first_name}”.

The way that custom variables know which name to add is by looking at the .csv file that you uploaded when you first created the campaign. When you create a cold email campaign with a tool like Emailchaser, you need to upload your leads (as a .csv file) to your campaign. This .csv file has information about each lead, such as their first name, job title, city etc, and it can add this information dynamically into each email through custom variables.

What is an example of a custom variable?

As mentioned above, the most common custom variable is the {first_name} variable.

Other popular custom variables include: {job_title}, {company_name} and {city}.

screenshot showing company name custom variable in email

For example, in your cold email, you might write something like: “I’m reaching out to people in {city}” or “Is {company_name} looking to hire more developers in the next couple of quarters?”.

There are an endless number of ways to use custom variables, but I recommend that you spend a lot of time thinking about how best to implement them. If used incorrectly, they can do more harm than good.

How to use custom variables in your cold emails

The only way to use custom variables is by using a specialized cold email software (like Emailchaser).

When you create a cold email campaign in Emailchaser, you will be asked to upload your leads to the campaign.

screenshot showing page in Emailchaser where you can import leads into a campaign

You will upload your leads as a .csv file, which will contain a column for each custom variable, such as First Name, Job Title etc.

You can learn more about how to import leads into Emailchaser in my article How To Import Leads Into Emailchaser.

Although this might sound confusing, it’s actually a simple process. Emailchaser makes it easy by giving you a .csv file template that you can add your leads to.

Common mistakes

Custom variables are very effective when used correctly.

However, if used incorrectly, they will decrease your response rate because your recipients will know that you are sending the same email to others, which will cause them to not respond.

Using bad data is the number one mistake that people make when using custom variables.

If the data in your .csv file is bad, then the data being inserted into your emails won’t look real. It will be obvious to your recipients that you are using a tool to automatically insert data into your emails, and they won’t think that you are sending them a personalized one-to-one email.

screenshot showing a csv file with lead data

An example of this would be if your .csv file said something like “CTO, Dad & Tech Evangelist” as the job title for one of your leads.

In the above example, it would be very obvious that you scraped this job title from the lead’s LinkedIn profile (or other lead source). If you actually sent a real personalized cold email, you would’ve just written “CTO”.

If you are looking for a way to find leads and ensure that the data in the .csv file is accurate and not full of errors, then I recommend that you use Emailchaser’s LinkedIn Email Finder.

screenshot showing Emailchaser's LinkedIn Email Finder extension

We built our LinkedIn Email Finder to only add correct data to the exported .csv file, meaning that when you send your cold email campaigns, your custom variables will add data that looks real, ensuring a high response rate.

Frequently asked questions

Should you use custom variables in your cold emails?

If you are sending a high volume of cold emails, then you should use custom variables, as it’s the only way to add personalization at scale.

Can you use custom variables in Gmail?

You cannot add custom variables in Gmail. You need to use a specialized cold email software (like Emailchaser) to add custom variables.

Final thoughts

Custom variables are one of the best ways to add personalization to your cold emails at scale.

If you are sending a low volume of emails, then you don’t need to use custom variables. If you are manually writing each email for each lead, then you don’t need to use them.

On a related note, you should check out my article How To Personalize Your Cold Emails At Scale. In this article, I show you how to personalize your cold emails at scale by using custom variables.

You can also read my other article Should You Use AI Personalized First Lines When Sending Cold Emails?

picture of George Wauchope

Article by

George Wauchope

Founder of Emailchaser.

I have been working in the sales & marketing industry for nearly a decade.

When I’m not working on my business, I enjoy eating sushi & doing jiu-jitsu.

About the author