Understanding ramping vs. warming

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You will learn

Learn more about the differences between warming and ramping, and when to perform either as you start with email marketing or edit your sending infrastructure. These terms are often used interchangeably, but it’s important to understand the differences of when they are specifically applied.

Understanding warming vs. ramping


All Klaviyo customers sending from a new dedicated infrastructure (IP or domain) must complete the correlating IP or domain warming. Warming occurs when you introduce a new or “cold” IP (i.e., an IP address that has not been used to send emails in the last 30 days) or new or “cold” sending domain (i.e., a domain that has been registered in the last 30 days or has never been used to send emails). Warming is the period of time in which you are establishing a reputation as a legitimate or “good” email sender.

Ramping is a process that aids in the overall warming process to become a reputable sender, whether you are using a dedicated or shared IP. When ramping a dedicated IP, this will be part of your overall warming process as it relates to your new infrastructure. Ramping shared IP’s involves new customers needing to warm their reputation relative to their new relationship with Klaviyo IPs.

Ramping involves starting out with smaller volumes of email sends, and then gradually increasing that volume over time. Depending on the volume of email that you send, the entire warming process may continue after you have fully ramped or sent all of your emails. For example, ramping to a 100k email volume may take as little as 10 days, but your email service provider (ESP) or a mailbox provider (MBP) typically take up to 30 days to make an initial decision on your reputation. During this time, you may also note that your email performance (i.e., opens and clicks) can fluctuate for up to ~120 days while your reputation is validated.

Common scenarios for warming and ramping

Now that you understand the definitions, let’s walk through common scenarios of when you will use warming and ramping. In each scenario below, you will identify which process, ramping or warming, should be used and how.

  • Mailbox provider (MBP) introduction
    • Ramping
      Ramping your email sending volume is used to introduce a change in infrastructure to the MBP. This is a key component of warming.
    • Warming
      Warming is used to establish a positive reputation with the MBPs for a new or “cold” IP or new or “cold” sending domain.
  • Email service provider (ESP) introduction (i.e., platform introduction process)
    • Ramping
      Ramping your email or sending volume is an essential function for onboarding responsibly to Klaviyo or any new ESP.
    • Warming
      Warming is used to establish a reputation as a sender in the Klaviyo shared network. Once a sender establishes a reputation, they graduate to the appropriate shared infrastructure.
  • Sending without historical engagement data
    • Ramping
      Ramping your email or sending volume if you have no engagement data to start with is a great way to slowly establish engagement data with less risk.
    • Warming
      Since having no historical engagement data can hinder you from becoming a reputable sender, warming is necessary in order to establish a positive reputation with your ESP.
  • Holiday sending
    • Ramping
      Ramp your email volumes during a time of year when there are significantly more emails being sent overall (e.g., Black Friday or Cyber Monday).
    • Warming
      Establish a reputation with the MBP to be able to send at a significantly higher volume.
  • Reputation repair
    • Ramping
      When your sender reputation is having issues, a common practice is to drop down to sending to only highly engaged recipients. Once your email performance improves, you can ramp back up to the engagement volume and frequency that you normally send.
    • Warming
      Also known as “rewarming” (i.e., typically used in times of reputation repair), this is the period it takes to reset your poor reputation with a MBP. Keep in mind that this process is difficult and often time-consuming, compared to following best practices and avoiding any reputation problems to begin with.

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