“Warm up” involves sending a small and progressively increasing volume of emails to start building a positive sender reputation.
Emails received from a new or unknown sending environment are closely analyzed by Internet Service Providers, or ISPs. These ISPs analyze based on sending volume, frequency and subsequent recipient reaction to gauge the legitimacy of your emails and determine if they are worthy of inbox placement.
Necessity of Warm Up
Large volumes of emails sent from an untrusted sender often result in messages being rejected or sent to the spam folder. As a result, all new SocketLabs accounts are rate limited to help our customers establish a positive sender reputation before sending high volumes. By starting with a positive sender reputation through warm up, your mail has a higher likelihood of reaching the inbox.
Warm Up at SocketLabs
Rate limiting, also known as throttling, occurs inside the SocketLabs network. This does not affect the rate at which we will accept your messages at our SMTP gateway, or via our Injection API. Delivery restrictions vary depending on several factors, including the plan volume and type of mail processing associated with your account. Delivery rates start as low as 50 messages per hour per domain.
Delays in message processing are most likely to affect customers attempting to send marketing messages in large volumes from a new server during warm up.
You will see messages in your queue that don’t flow in and out immediately. This is expected behavior as we receive the mail and release based on our warm up settings. Our platform will automatically increase delivery rates as mailbox providers get used to seeing your messages.
You can view the mail flow by selecting the ‘Hourly Overview’ option from the main dashboard under the Overview section dropdown. This report shows the messages received and the flow in which they are going out. As you warm, the hourly report should show the mail releasing closer and closer to the time received.
Length of Warm Up
The length of warm up is dependent on multiple factors, including:
- Sending volume and frequency
- The type of mail processing associated with your account
- The quality of your sending statistics
Low volume transactional senders may see warm up end within a single day, whereas high-volume marketers may have their delivery rates throttled for a longer timeframe.