Notice: Potential Messaging Delays During Peak Campaign Periods

We want to keep you informed about potential delays in message delivery during peak periods such as the holiday shopping season. Such periods typically see a significant increase in message volumes, which can place additional demand on carrier networks and may result in delivery delays.

To help you navigate these peak messaging periods, we've provided important insights and recommendations below to optimize your campaigns for the best possible outcomes.

Key Dates

• Black Friday: November 27, 2026 
• Cyber Monday: November 30, 2026 
• Political Messaging: Elevated traffic is expected throughout political campaign periods, particularly leading up to major elections, debates, voter outreach events, and other high-profile political activities.
   

What Causes Delays?

• Increased Message Volume - During peak times, millions of businesses utilize SMS and MMS messaging to engage with their customers. This surge in activity can lead to temporary congestion within carrier networks, affecting delivery times.
   
• Internal Queuing - Messaging capacity to carriers is a shared resource among all customers, operating on a best-effort basis. While we commit to certain throughput rates, these may not always reflect the speed at which messages are transmitted to carriers.
   
• Carrier Network Capacity - Messaging capacity is also shared among all aggregator partners. While carriers strive to manage high volumes effectively, simultaneous high-volume campaigns can occasionally lead to congestion, impacting delivery times.
   

What to Expect

• Potential Delays - You may experience longer delivery times for some messages, especially during high-traffic hours. For updates on severe degradation or significant delays, please refer to our status page.
   

Actions We Are Taking

• System Optimization - We have enhanced our system capacity to handle increased traffic and are collaborating closely with carriers to maintain optimal throughput during peak times.
   

Recommendations for Customers

1. Plan Ahead - If possible, schedule your messages earlier in the day or prior to peak dates to minimize the risk of delays.
    
2. Stagger Campaign Messaging - For large campaigns—particularly around significant events like Black Friday and Cyber Monday—consider staggering your messages throughout the day to ensure timely delivery.
   
    
3. API Limitations - Be aware that there may be throughput limits on your API requests. While we accept messages at your configured rate, exceeding these limits could result in rejected messages that require resending. For high-volume campaigns, we recommend planning your sends according to your total volume and maximum throughput limits.
    
4. Retrying Messages with Backoff - Implement a retry strategy with exponential backoff for any failed messages. This approach helps prevent overwhelming carrier networks by spacing out retries over time, reducing the risk of congestion.
    
5. Avoid Sending at the Top of the Hour - Sending messages at the top of the hour can lead to delays, as this is when Mobile Network Operators (MNOs) experience their highest traffic volumes. Many businesses schedule their communications to coincide with the beginning of the hour, resulting in congestion. By choosing alternative times, you can help ensure faster delivery and reduce the likelihood of your messages getting stuck in a queue.
    
6. Consider Alternate Sending Times During Peak MNO Network Hours - Peak MNO network activity typically occurs from 9:30 AM to 3:00 PM EST. During these hours, networks are heavily utilized for various activities, including voice calls and data usage. To optimize delivery, consider scheduling your messages outside of these peak times, such as early in the morning or later in the evening, when network congestion is likely to be lower.
    
7. Use a Shorter Delivery Validity Period (Where Supported by Our APIs) - Implementing a shorter delivery validity period can be beneficial, as it prompts MNOs to prioritize the message delivery process. A shorter validity window encourages the network to make timely delivery attempts, reducing the risk of messages becoming stale or irrelevant. Please check our API documentation for specifics on how to adjust the validity period for your campaigns.
    
8. Avoid Using Multipart Messages if Possible - Multipart messages, while useful for conveying longer content, can complicate delivery and increase the chances of delays. Multipart messages must be processed and delivered individually, which can lead to issues if any segment is delayed. To streamline delivery and enhance the user experience, aim to keep your messages concise and within the limits of a single SMS whenever possible.
    

Our Commitment

We are dedicated to providing the highest level of service during these peak periods and will keep you informed of any issues or disruptions. Our team is continuously monitoring the situation to ensure timely delivery whenever possible. For updates on severe degradation or significant delays, please check our status page.
 

Contact Us

If you have any questions or concerns about your messaging campaigns during these peak seasons, please don't hesitate to reach out to our support team. We're here to help!

Learn more about and try out Sinch SMS

Take a look at the Sinch SMS Product page to learn more about our SMS products, or click here to sign up to our self-service portal and get started today.