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Message Not Delivered:
A Deep Dive into SMS Testing

If you own a cell phone, you’ve probably received a similar SMS at one point:

  • Your one-time password is 12345.
  • Your flight #777 is departing from gate A1
  • Your order is ready for a pick-up
  • Your Covid-19 test results have been sent to your email

What unites all these text messages?

It’s crucial that they reach the recipient. Imagine one of these SMS being cut, changed or even undelivered. This could cost a company a loss of money, reputation or even a customer.

For companies that rely heavily on mass messaging, the stakes are high. A single misstep in SMS delivery can lead to significant operational and communication setbacks. This is where the strategic importance of SMS testing becomes evident.

At TelQ, we have dedicated ourselves to mastering the SMS testing. Our experience has taught us that thorough and effective SMS testing is not just a technical requirement; it’s a critical component of maintaining seamless communication.

Here, we’ll explore the essential reasons why SMS testing should be a priority, examine the various methods available, and discuss how to choose the right tools for the task. In addition, we will share best practices that elevate SMS testing from a routine task to a crucial business strategy.

Join us as we explore the nuances of SMS testing, where every message’s journey from your server to recipient is crucial to your business success.

Defining SMS Testing

SMS testing, at its core, is a systematic process aimed at ensuring that text messages are delivered to your customers accurately and promptly. It involves verifying and validating the functionality and performance of SMS services to ensure they meet the required standards of quality and efficiency. This is particularly critical in enterprise environments where communication accuracy is not just expected but essential.

SMS testing isn’t just about checking if messages are delivered; it’s about guaranteeing operational efficiency and maintaining customer trust. A well-executed SMS testing strategy ensures that messages reach their intended recipients promptly and accurately, which is vital for time-sensitive communications and maintaining customer engagement.

How to Test SMS

In general, there are three practical methods to test SMS. Each comes with its own context of use:

1. Manual testing with personal and colleague numbers:

Approach: Involves sending test SMS messages to a set of known numbers of real people from your circle to check for delivery accuracy and timeliness.

Context of use: Ideal for initial, small-scale testing or when trying to replicate a specific user’s experience.


  • Direct and straightforward;
  • Allows for immediate and real feedback;
  • Picks up errors if they can be recreated with this specific testing environment;
  • Helps to quickly evaluate and compare SMS vendors.


  • Not scalable for larger volumes;
  • Lacks diversity in network coverage and may not reveal issues with different mobile operators or geographical locations.

2. Using bulk SMS vendor’s testing functionality:

Approach: Many bulk SMS vendors provide built-in testing functionalities within their platforms, allowing you to conduct tests through their system.

Context of use: Suitable for testing within the constraints of your existing SMS service provider’s network.


  • Convenient and easy to use within the vendor’s ecosystem;
  • Can provide insights into the performance on the vendor’s network.


  • Limited to the vendor’s network and capabilities;
  • The insights gained might be somewhat constrained, as the data provided is through the lens of the vendor’s ecosystem. There might be a tendency for these results to be more favorable or not fully disclose performance issues that could emerge in a less controlled external environment.

3. Utilizing a stand-alone SMS testing tool:

Approach: Third-party SMS testing tools offer a more comprehensive testing environment, simulating a wide range of scenarios and network conditions. These tools have a broad test numbers coverage that allows getting better quality of testing.

Context of use: Best for in-depth, thorough testing across various networks and global locations. These tools are particularly useful for businesses that require extensive and unbiased testing coverage across diverse communication channels.


  • Extensive coverage: Provides broad testing coverage, not confined to any specific vendor’s ecosystem.
  • Unbiased and truthful data: Offers more truthful and unbiased data, essential for an accurate assessment of SMS service quality.
  • Capability to identify fake delivery reports: Crucially, these tools can detect fake delivery reports (fake DLRs), an essential feature for verifying the actual delivery status of messages. This helps businesses in ensuring the reliability and integrity of their SMS communication.
Example of fake DLR detection with TelQ tool
A real test made on the TelQ SMS testing platform showed that the fake DLR was received
  • Pinpointing potential issues: Capable of uncovering a wide spectrum of potential issues, ranging from technical glitches to content inaccuracies.
  • Vendor evaluation and selection: Unbiased SMS testing tools are instrumental in evaluating the performance of different SMS vendors, helping businesses make informed decisions when selecting or changing their SMS service provider. Compared to the first method, SMS testing tools allow a more complex approach to vendor’s selection.


  • Setup Complexity: The setup can be more complex compared to basic SMS testing methods. This is why at TelQ, the customer’s learning journey starts with a discovery call and a demonstration of the platform. The process is further supported by comprehensive product documentation and the dedicated assistance of our support team.
  • Additional Expenses and Expertise Required: Requires additional investment; using these tools effectively requires an understanding of their features and capabilities.

Each method serves a specific purpose in the overall SMS testing strategy. Manual testing is quick and simple for basic checks, vendor testing functions offer convenience within a known system, and independent testing tools provide the most comprehensive and robust testing environment.

In the next section, we’ll delve into what specific aspects of SMS services should be rigorously tested to maintain high standards of communication quality.

Who Needs SMS Testing

SMS testing is vital across various sectors, each with its unique communication challenges and requirements. Here are the key entities that need robust SMS testing for their special needs:

  1. Financial Institutions and Banks
    • Why They Need It: For financial entities, the accuracy and promptness of SMS alerts about transactions, fraud warnings, and account updates are critical. Errors can lead to customer dissatisfaction or financial losses.
    • Specific Needs: Security of messages, maintaining compliance with financial regulations, and delivering timely alerts.
  2. Airlines
    • Why They Need It: Airlines use SMS for flight updates, booking confirmations, and check-in reminders. SMS testing ensures that critical information regarding travel plans is communicated effectively.
    • Specific Needs: Timely and accurate updates to passengers, managing communications during operational disruptions, and maintaining customer satisfaction.
      Sample SMS test for the airlines
      Example of SMS test with TelQ tool for the airlines
  3. Hospitality Industry
    • Why They Need It: SMS testing is essential for booking confirmations, service notifications, and guest communication.
    • Specific Needs: Providing personalized and timely communication, enhancing the guest experience, and efficiently managing reservations and inquiries.
  4. Healthcare Providers
    • Why They Need It: Healthcare institutions use SMS for appointment reminders, patient updates, and health advisories. Delays or errors can lead to missed appointments or vital information not being communicated.
    • Specific Needs: Compliance with health information privacy standards, ensuring message reception and comprehension by patients.
  5. E-commerce and Retail Businesses
    • Why They Need It: SMS is a tool for marketing, customer service, and order updates in these sectors. Ineffective messaging can lead to lost sales opportunities and poor customer experience.
    • Specific Needs: Timely delivery of promotional and transactional messages, ensuring content accuracy.
      Sample SMS test for the ecommerce store
      Example of SMS test on TelQ platform for the ecommerce store
  6. Logistics and Transportation Companies
    • Why They Need It: For these companies, SMS notifications are essential for delivery updates, logistics coordination, and customer service.
    • Specific Needs: Real-time updates, high reliability in message delivery, and scalability during peak operational times.
  7. Government and Public Service Agencies
    • Why They Need It: These agencies use SMS for public alerts, informational campaigns, and service notifications. The information needs to be clear, accurate, and timely to maintain public trust and efficiency.
    • Specific Needs: Reaching a wide audience reliably, adhering to public communication standards, and ensuring message clarity.
      A real-life example of SMS encoding problem
      A real-life example how the author unsuccessfully tried to connect to the public internet of the Malmo city
  8. Telecommunications and IT Services
    • Why They Need It: These sectors rely on SMS for service updates, customer notifications, and security alerts (like two-factor authentication).
    • Specific Needs: Ensuring high security and reliability, managing large volumes of messages, and maintaining technical accuracy.

Regular and rigorous SMS testing in these sectors ensures communication accuracy, timeliness, and compliance, which are pivotal for operational success, customer experience, and safety. Tailoring SMS testing strategies to these specific needs ensures that messaging services function as an effective and reliable communication channel.

What to Test in SMS and Why

Effective SMS testing must encompass a range of aspects to ensure each message’s integrity, timeliness, and effectiveness. Here’s a detailed look at what needs to be tested in SMS communications:

1. Delivery

What to Test: Verification of whether the SMS is reaching the intended recipients.

Why It’s Important: Ensures that critical communications are not lost or undelivered. In cases like emergency alerts or transaction confirmations, undelivered messages can have serious implications. Regular testing of delivery helps maintain the reliability of the service.

Things to consider: You shouldn’t always trust the delivery report from your provider. While outright malicious manipulations are relatively rare, still a lot of things can go wrong and result in an unreliable delivery report.

TelQ uses advanced methods to verify actual SMS delivery. We employ unique, non-disclosed technology to track SMS delivery accurately. This ensures our clients receive reliable, real delivery statuses directly from the nodes in our coverage.

2. Latency

What to Test: The time taken for an SMS to be delivered from the sender to the recipient.

Why It’s Important: Low latency is crucial for time-sensitive messages, such as OTPs or urgent alerts. High latency can lead to delays that may disrupt user experience and operational workflows.

3. Changes in the Content

What to Test: Consistency of the SMS content throughout the transmission process.

Why It’s Important: It’s essential that the content received by the end user is exactly as intended by the sender. Alterations can lead to misunderstandings or misinformation, especially in sectors like healthcare or finance where accurate information is paramount.

Example from one of SMS tests on TelQ platform with modified message content
An example from the tests on TelQ platform how a very professional SMS can end up looking spammy

Fun fact: As you may know, all emojis have a set of text symbols that encodes them. For example, 0x16F03 would result in 🙂. That being said, random alterations of SMS content might result in unexpected emojis being delivered instead of your carefully crafted text. And not all emojis are created equal…

4. Changes in the Sender ID

What to Test: Accuracy of the Sender ID as it appears to the recipient.

Why It’s Important: A correct Sender ID fosters trust and recognition. Incorrect or misleading IDs can lead to confusion, reduce the effectiveness of the message, and even pose security concerns.

TelQ report about Sender ID modification in a test message
An example from one of the tests on TelQ platform how Sender ID lost it’s branding on the way

Things to consider: Sender ID is a subject to intricate compliance regulations. Testing the consistency of Sender ID in various countries and networks helps to ensure that you are staying compliant.

5. Fake Delivery Reports

What to Test: The authenticity of delivery reports provided by carriers or service providers.

Why It’s Important: In some cases, carriers or SMS service providers might send fake delivery reports. This can lead to a false sense of confidence about the reach and effectiveness of your SMS campaign or communication. Testing for fake delivery reports helps ensure that you have accurate data about message delivery, allowing for more informed decisions and strategies.

Things to consider: Fake DLRs are one of the main reasons to choose a third-party tool for SMS testing. Here at TelQ we made it our mission to bring transparency to SMS testing and to fight fake DLRs that undermine the reputation of the telecom industry. Our platform compares the delivery report with the real status from the recipient device and promptly notifies about detected fake DLRs.

6. Technical Attributes

What to Test: Various technical aspects of SMS, such as encoding, segmentation, and concatenation.

Why It’s Important: These attributes affect how messages are processed and displayed. Proper testing ensures messages are readable and coherent, regardless of the recipient’s device or network.

Incorporating these testing elements helps businesses enhance the reliability and effectiveness of their SMS communication strategies. This is particularly vital in scenarios where accurate and reliable messaging is critical, such as emergency communications, transaction notifications, and time-sensitive updates. Regular and thorough SMS testing is therefore not just a technical necessity but a fundamental part of a robust communication strategy.

How to Choose a Tool for SMS Testing

Selecting the right SMS testing tool is crucial for ensuring effective and reliable communication. Here are key criteria to consider when choosing an SMS testing tool:

  1. Coverage and Network Compatibility: The tool should support a wide range of networks and countries globally to ensure comprehensive testing coverage. Ideally, it should also be able to test ported numbers.
    Tip: Analyze the networks where you typically send your campaigns, focusing especially on smaller networks and ported numbers. While many tools cover the most popular destinations, they may not extend to certain smaller countries, less common networks, or unusual combinations involving ported numbers. It’s important to ensure coverage for these areas to maintain comprehensive campaign effectiveness.
  2. Testing Capabilities: Look for tools that offer a variety of testing features, including delivery verification, latency measurement, content integrity, and Sender ID accuracy.
  3. Detection of Fake Delivery Reports: An essential feature where the tool can identify false delivery confirmations, providing a more accurate assessment of message delivery.
    Tip: It can happen that an SMS testing tool does not change their numbers frequently, and as a result may show a fake positive result. This phenomenon occurs due to whitelisting, when test numbers become known to the user’s SMS vendor.
  4. User Interface and Ease of Use: The tool should have a user-friendly interface, making it easy to set up tests, interpret results, and integrate with existing systems.
  5. Customization and Flexibility: The ability to customize tests based on specific needs, such as different message types, frequencies, and volumes, is important. For example, TelQ platform has a unique feature Dynamic Test ID. It has broad customization options for the test ID to make a message look like a real one and avoid whitelisting.
    Dynamic Test ID customization options in TelQ tool
    Dynamic Test ID customization options on TelQ platform
  6. Reporting and Analytics: Comprehensive reporting features that offer insights into test results, enabling you to make data-driven decisions.
    Interface of performed tests analytics in TelQ tool
    Tests Analytics interface in TelQ SMS testing tool

    Technical Support and Documentation: Reliable customer support and thorough documentation are vital for troubleshooting and maximizing the tool’s capabilities.

  7. Cost-Effectiveness: Evaluate the tool’s pricing in relation to its features and the value it brings to your SMS testing needs. TelQ tool has two pricing models to accommodate different needs: prepaid (perfect for the start) and postpaid (perfect for the large volumes).
  8. Scalability: The tool should be scalable to accommodate growing volumes of SMS testing as your business needs evolve.

Choosing the right SMS testing tool requires careful consideration of these factors and thorough testing of the tool’s capabilities to ensure it meets your specific SMS testing needs effectively.

Do’s and Don’ts for Effective SMS Testing

Effective SMS testing ensures that your messaging service operates as intended, providing accurate and reliable communication. Here are some best practices to guide you through SMS testing:

1. Use Content That Resembles Live Traffic

Do: Strive to make SMS content resemble transactional messages. This includes formats like OTPs, login codes, balance information, or other typical traffic your service handles. By mirroring real traffic, test results are more likely to reflect actual performance under live conditions.

An example of how not to test an SMS
A big no-no in SMS testing

Don’t: Avoid using words like “testing,” “test,” or their translations in your test messages. Such terminology might signal to vendors that you are conducting quality checks, leading to potential whitelisting of your content and skewing the test results. Imagine yourself an SMS provider. Would you send a fake DLR to the sender of this text: “Test message”?
Pro Tip: We’ve created a special feature to make tests from our platform look more natural. It’s called Dynamic Sender ID and it allows you to place test ID anywhere in the message and even choose it’s format from numeric, alphanumeric, alpha and WhatsApp code.

2. Configure SMPP Connection Properly

Do: Create an SMPP bind between the client and TelQ, not directly between TelQ and vendors. This approach makes it less likely for the vendor to recognize that quality checks are being performed. The routing should be managed on the client’s side, keeping the TelQ SMS testing platform concealed.

Pro Tip: Diversify the timing of your testing campaigns. Avoid scheduling them at the same hour every day, as this makes your testing traffic less noticeable.

3. Never Escalate Test Numbers

Do: If a problem is detected on a route, choose a number from your live traffic to escalate instead of the test number itself. This helps in maintaining the integrity of your test numbers.

Don’t: Avoid escalating test numbers directly to the vendor. Doing so can lead to the whitelisting of these numbers, which compromises the authenticity of your test results. TelQ aims to keep the pool of test numbers healthy to ensure reliable testing outcomes.

4. Set Up Alerts to Detect Fake Delivery

Do: Set up scheduled tasks and email alerts to notify you in case of fake delivery or changes in SMS features, such as manipulated sender IDs and content. Customize rules for these alerts in various combinations and direct them to multiple email addresses. This practice helps you stay informed about any irregularities on the tested routes.

By adhering to these do’s and don’ts, you can conduct SMS testing more effectively, ensuring that your messaging services are reliable and accurately reflect real-world performance. These practices are key to identifying and addressing issues proactively, thus maintaining the quality and trustworthiness of your SMS communications.

The Conclusion

In summary, every SMS matters. For airlines, e-commerce, banks and many more industries accurate SMS delivery is key.

At TelQ, we understand this and we strive to help every SMS find a way to its intended recipient. Our approach to SMS testing goes beyond technical needs. It’s about uninterrupted, trustworthy communication. We tackle challenges like fake delivery reports, split routing, message trashing and more, setting new industry standards.

If you are interested in TelQ services, register for a free trial of our platform. Our team of testing professionals will be happy to help you start your journey of route verification and messaging excellence. After the registration we’ll be in touch with you for scheduling product demo and discussing how TelQ can fit your specific needs.

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