Service Level Agreement

Our Service Level Agreement describes the Availability of Services that users can expect to receive from MailerSend.

Last updated on May 06, 2024

The MailerSend Service Level Agreement (“SLA”) is a part of the MailerSend Terms of Use (“ToU”). The SLA describes the Availability of Services that users can expect to receive from MailerSend for the duration of using its Services. It also describes how we reimburse Service Credit in case of Error. 

Please note that throughout the SLA, "we," "us," and "our" refer to MailerSend, and "you," "your," and "yours" refer to the user. 

This SLA enters into force (a) from the day you agreed with our ToU and continues for an indefinite period of time; or (b) on June 15, 2021 if you have become our client before June 15, 2021 and continues for an indefinite period of time. 

If there is any conflict between this SLA and the ToU, the relevant terms of the SLA shall take precedence. 

1. Definitions

1.1. Availability. It is calculated for each 5-minute interval as the percentage of Requests processed by MailerSend that do not fail with Errors and relate solely to the communication API. If you did not make any Requests in a given 5-minute interval, that interval is assumed to be 100% available; 

1.2. Error. Means any request that fails due to MailerSend internal service error; 

1.3. Force Majeure event. Means an event beyond the control of MailerSend that prevents it from complying with this SLA, including but not limited to: 

  • Act of God (such as, but not limited to, fires, explosions, earthquakes, drought, tidal waves, and floods); 

  • War, hostilities (whether war be declared or not), invasion, act of foreign enemies, mobilization, requisition, or embargo; 

  • Rebellion, revolution, insurrection, or military or usurped power, or civil war; 

  • Contamination by radio-activity from any nuclear fuel, or from any nuclear waste from the combustion of nuclear fuel, radio-active toxic explosive, or other hazardous properties of any explosive nuclear assembly or nuclear component of such assembly; 

  • Riot, commotion, strikes, go-slows, lockouts or disorder; or 

  • Acts or threats of terrorism. 

1.4. Monthly Uptime Percentage. It is calculated as the average of the Availability for all 5-minute intervals in a monthly availability status report; 

1.5. Request. Means calling an endpoint of any API hosted on MailerSend; 

1.6. Services. The transactional email and SMS (communication) services described in the ToU. 

1.7. Service Credit. It is credit in US Dollars that we may credit back as a discount regarding future payments to an eligible account; 

1.8. Scheduled Maintenance. Means planned interruptions of MailerSend Services to make changes to MailerSend systems. MailerSend regularly evaluates app traffic patterns in order to determine low usage times in which to perform Scheduled Maintenance. Scheduled Maintenance may include outages; 

1.9. Uptime Service Commitment Guarantee. MailerSend will use commercially reasonable efforts to make our Service available with a Monthly Uptime Percentage of at least 99.5% during any monthly availability status report. 

1.10. Communication. Means transmissions sent via API (i.e. via email or SMS). 

2. Scope

2.1. This SLA applies only to the transactional email and SMS services described in the ToU. This SLA does not apply to any software, equipment, services, or other parts of an information technology system that are not purchased from or managed by MailerSend.  

3. Obligations

3.1. Obligations of MailerSend: 

3.1.1. Ensure that the Services are available to the user in accordance with the Uptime Service Commitment Guarantee, during any monthly availability status report; 

3.1.2. Take steps to escalate, diagnose, and resolve issues in an appropriate and timely manner, including the allocation of a sufficient number of skilled staff and the collection of necessary information; 

3.1.3. Maintain clear and timely communication with users at all times. 

3.2. Duties of the user: 

3.2.1. Use the Services as intended under the ToU; 

3.2.2. Notify MailerSend of issues or problems in a timely manner and as thoroughly as is possible; 

3.2.3. Cooperate with MailerSend in its efforts to escalate, diagnose, and resolve issues by providing timely and accurate responses to requests for information. 

4. Service Credits

4.1. In the event that our Services do not meet the Uptime Service Commitment Guarantee, the user will be eligible to receive a Service Credit as described below. 

4.2. Service Credits are calculated as a percentage of the total charges paid by you to MailerSend for the monthly billing cycle in which the Monthly Uptime Percentage fell within the ranges in the table below: 

Covered Service 

Monthly Uptime Percentage 

Service Credit Percentage 

API uptime 

99.0 % < X < 99.5 % 

5 % 

95.0 % < X < 98.9 % 

10 % 

X < 95.0 % 

15 % 

SMTP uptime 

99.0 % < X < 99.5 % 

5 % 

95.0 % < X < 98.9 % 

10 % 

X < 95.0 % 

15 % 

4.3. We will apply the Service Credits as a discount for future payments regarding MailerSend Services only. 

4.4. At our sole discretion, we may issue the Service Credit to the credit card you used to pay for the billing cycle in which the Uptime Service Commitment was not met.  

4.4. Please note that Service Credits will not entitle users to request any refund or other payment from MailerSend. A Service Credit will be applicable and issued only if the credit amount for the applicable monthly billing cycle is greater than one US Dollar (USD 1). Service Credits shall not be transferred or applied to any other account.  

5. Credit Request

5.1. To receive a Service Credit, you must submit a claim by contacting us. To be eligible, the credit request must be received by MailerSend by the end of the second billing cycle after which the incident (Error) occurred and must include: 

  • The dates and times of each lack of Availability incident that you are claiming; 

  • The affected account(s); 

  • The billing cycle that you are claiming Service Credits for; and 

  • Your request logs that document the Errors and corroborate your claimed outage (any confidential or sensitive information in these logs should be removed or replaced with asterisks). 

5.2. If the Monthly Uptime Percentage of such a Request is confirmed by us and is less than the Uptime Service Commitment Guarantee, we will then issue the Service Credit to you within one billing cycle following the month in which your Request is confirmed by us.  

5.3. Please note that your failure to provide the Request and any other required information will exclude you from receiving a Service Credit. 

6. Exceptions regarding issuance of Service Credit

6.1. Users shall not be entitled to receive Service Credit for Service interruptions during a Scheduled Maintenance: 

6.1.1. For a Scheduled Maintenance of 2 hours or less in duration, MailerSend will make best efforts to notify users no later than 48 hours prior to the Scheduled Maintenance; 

6.1.2. For a Scheduled Maintenance of more than 2 hours in duration, MailerSend will notify users no later than 120 hours prior to the Scheduled Maintenance; or

6.1.3. If a Scheduled Maintenance is expected to take less than 30 minutes, MailerSend may perform it without prior notice to the users, with efforts to minimize Service disruption.   

Notice for the purpose of Scheduled Maintenance will be sent via email to MailerSend users. 

6.2. The Service Credit commitment does not apply to any unavailability, suspension or termination of MailerSend Services in the following cases:  

6.2.1 The result from any delays or failure in performance of any part of the Service caused by a Force Majeure event. 

6.2.2. That result from any voluntary actions or inactions by you or any third party (e.g., misconfiguring credential settings, making encryption keys inaccessible, access being restricted due to abuse of our API, etc.);  

6.2.3. That result from your equipment, software or other technology and/or third party equipment, software or other technology (other than third party equipment within our direct control);  

6.2.4. That result from you not following the best practices described in the MailerSend Developer Guide and Help section

6.2.5 That result from the use of the Services in a manner by the user that is contrary to the MailerSend ToU. 

6.3. The Service Credit Commitment does not include the deliverability rate (average rate of delivered communication for all 5-minute intervals in a monthly billing cycle) and the delivery time (average time sent communication takes to be delivered for all 5-minute intervals in a monthly billing cycle). These metrics, by their nature, are unpredictable as they depend on independent Internet Service Providers (“ISP”), network carriers and the types of communication sent. Thus, MailerSend cannot possibly guarantee them.

6.4. MailerSend is not liable for the delivery time comprised between the sending and the delivered events. While we commit to delivering messages promptly from our end, factors such as network congestion, routing inefficiencies, or delays within the recipient's network are beyond our control and may affect delivery times.

6.5. MailerSend is responsible for initiating and transmitting SMS messages up to the point of handover to the relevant network carrier. However, MailerSend cannot guarantee the delivery speed from that point onwards, as it is subject to the efficiency and capacity of the recipient's network and the recipient's device capabilities.

7. Changes

MailerSend reserves the right to change this SLA at any time. If we decide to change this document, we will post changes on this page. If MailerSend changes this SLA, the date below will be changed to reflect the publication date of the most recent version. Thus, MailerSend encourages you to check this SLA periodically.