Use and abuse of e-commerce APIs by management systems: a warning from a systems engineer to a developer

Introduction

Today, e-commerce is an integral part of our daily lives. The convenience of purchasing products online has transformed the commercial landscape, pushing many companies to create digital sales platforms. Among the most popular solutions we find open source CMS such as WooCommerce, PrestaShop and Magento, as well as SaaS or PaaS platforms like Shopify.

Self-hosted solutions like WooCommerce and Magento are primarily based on technologies like PHP and MySQL (or forks like MariaDB and Percona Server). While these technologies have been optimized over time with tools like OpCache and JIT compilation, they remain synchronous systems that often wait for responses from the database. Despite these limitations, strategic use of caching has helped mask these inefficiencies, providing seamless and engaging user experiences.

However, a crucial problem that is not yet fully understood concerns the use of the APIs of these CMS by management software or middleware. These tools are designed to manage warehouses, synchronize inventory or process orders through e-commerce platform APIs. This article, therefore, aims to be a warning to developers of such solutions.

If you are reading this article, chances are you are a middleware or management software developer. There is something important I want to tell you, on behalf of all the system administrators who share the same frustrations: it is essential to better understand the impact of your applications on server infrastructures and find solutions that respect these limits.

1. PHP is slow and MySQL even slower

PHP and MySQL, while being mature and widely used technologies, have intrinsic architectural limitations that cannot be completely overcome. PHP is a synchronous language: each operation is executed in sequence, and the life cycle of a PHP process inevitably includes moments of waiting, often related to responses from the database. This means that, even with the use of tools such as OpCache or JIT compilation, PHP remains a technology with limited performance compared to more modern asynchronous approaches.

MySQL, on the other hand, is a robust and versatile relational database system, but it is designed to operate on a model that easily becomes a bottleneck in the presence of unoptimized queries or large datasets. Any complex, or worse, poorly structured, query can require significant resources to be processed, directly impacting the overall performance of the system.

When using CMS like WooCommerce, PrestaShop or Magento, the situation becomes even more complicated.. These tools are designed to offer maximum flexibility and functionality, but are rarely optimized “out of the box” for high-traffic or heavy-load environments. The use of plugins and additional modules, often necessary to customize and improve the platform's functionality, adds complexity to the system: they increase the number of queries executed, the interdependencies between processes and, inevitably, response times.

Every API request sent by a management system or middleware amplifies these problems. A single API call can generate dozens of SQL queries on the database, chaining operations that involve not only the main tables (such as products or orders), but also metadata, complex relationships and additional plugins. This additional load, if repeated massively or uncontrolled, can quickly lead to server overload, degrading the user experience and putting the stability of the entire system at risk.

2. APIs are not cacheable

Unlike web pages that can benefit from a full-page cache (e.g., with Varnish), APIs cannot be cached in the same way. Each API request must be processed in real time, involving numerous server-side processes. This cycle begins with parsing the request (request body), runs SQL queries against the database, and ends with generating the response in JSON format. Unlike static content, APIs serve dynamic data, often unique for each request, making traditional caching impossible.

The result is that each API call introduces significant computational load on both the web server and the database. The performance of the infrastructure therefore depends entirely on the power of the server and the quality of the application code. Even with high-performance hardware, inefficient application routines can nullify any optimization efforts. Poorly designed queries, lack of adequate indexes and unoptimized PHP code can generate high response times and compromise the user experience.

Furthermore, server-side tuning – no matter how advanced – cannot compensate for massive or unrationalized API requests. Poor API management becomes a structural problem, which has negative repercussions not only on the e-commerce in question, but also on any services shared on the same server.

3. Not all e-commerce have Dedicated Servers

One aspect that developers often overlook is that not all e-commerce sites operate on Dedicated Servers. The early stages of an online business often see owners opting for shared hosting or cheap VPS solutions, attracted by the low costs. While these plans may be optimized for standard use, they are not designed to handle intensive loads such as those generated by massive API requests.

When a manager or middleware sends continuous streams of API calls, the entire server ecosystem can collapse. In shared environments, where multiple websites coexist on the same hardware, a single application that generates a high number of requests can monopolize resources, causing slowdowns or crashes for all other hosted sites. This not only negatively impacts the user experience of the e-commerce site involved, but can compromise the operation of other clients on the same server.

This situation can degenerate into a real DoS (Denial of Service) attack, even if involuntary., where the excessive number of API requests makes the server unable to respond adequately. End users experience errors, long loading times or service interruptions, while the system administrator is faced with a complex situation, with limited resources to intervene quickly.

Responsible API management is essential to avoid these problems. Developers and ERP owners must carefully consider hardware limitations and adopt solutions that minimize the impact of their applications on shared infrastructure.

The consequences of API misuse

API abuse has direct consequences for all parties involved:

1. End customers: they get a bad experience, with incomplete inventory updates or partially processed orders.
2. System administrators: they find themselves dealing with an unmanageable overload, with the added frustration of not being able to apply caching solutions.
3. Management developers: they receive complaints and requests for explanations, risking losing credibility and customers.

To avoid all this, it is essential to implement solutions that reduce the load generated by applications.

Practical advice for developers

To ensure effective and sustainable interaction between your management software and e-commerce platforms, it is essential to adopt methodologies that respect the limits of server infrastructures and optimize the use of resources. The following practical tips are designed to help you design more robust, efficient applications that guarantee an excellent user experience, minimizing the risk of overload or malfunction.

Implement a throttling system

Il throttling is a technique used to regulate the flow of requests sent to a server, limiting their frequency in a given time interval. This approach allows to avoid overloading the server, maintaining a balance between the processed load and the available resources. Throttling is particularly useful to prevent situations of excessive stress on server infrastructures, especially when using APIs that generate high computational loads.

For example, you can implement a throttling system by configuring a delay (e.g. via a command sleep) between requests, setting a maximum limit of one request per second. While your server may be able to handle more, maintaining a minimum interval of 0,5 or 1 second is a good practice to ensure stability and prevent unexpected overloads.

Furthermore, a well-designed throttling system does not have to be static, but dynamic and adaptive. This means that the request per second limit can be modulated based on the server's operating conditions. For example:

Low loads: When the server is underutilized, the system may slightly increase the number of allowed requests to optimize operations.

High loads: During times of increased server stress or slowness, throttling should automatically increase the delay between requests to lighten the load.

Integrating throttling into your applications not only improves server stability, but also ensures more fair and predictable resource usage. This is especially important in shared environments or when managing business-critical APIs.

Respect HTTP response codes

Respecting HTTP response codes is essential to ensure robust and stable operation of applications that interact with remote servers. When the server returns errors of type 500 (Internal Server Error), indicates that it is facing an internal problem or is under excessive load. These signals should be interpreted as critical by your application, which should react by implementing management strategies to prevent further overloads and improve the overall efficiency of the system.

Management strategies:

1. Resend failed requests
   Rather than immediately retrying a failed request, it is important to set a short wait interval before retrying. This approach, known as Retry Delay, allows the server to recover resources and reduces the risk of making the situation worse. The delay between retries can be:
   • Fixed: a constant time interval (for example, 5 seconds).
   • Incremental or exponential: The delay increases progressively with each subsequent attempt, for example 5 seconds for the first attempt, 10 for the second, and so on. This approach is useful for handling situations where the server requires more time to get back up and running.
2. Dynamically increase throttling
   If 500 errors persist, the system should automatically adapt the number of requests sent, increasing the delay between requests or reducing their frequency. This dynamic behavior ensures a more sustainable approach during load peaks, avoiding worsening the server conditions and still maintaining a minimum level of operation.

Benefits of adaptivity:

These strategies help manage system stress situations, such as:

• Promotions and traffic spikes: during special events that suddenly increase the number of users and requests.
• Bot or crawler attacks: situations where automatic access may generate unexpected loads.
• Random Loads: temporary overload conditions due to traffic fluctuations or limited resources.

By following these principles, your application will not only be more resilient, but it will improve the end-user experience, avoiding long outages and ensuring responsible use of server resources.

Handle HTTP 429 “Too Many Requests” Code Correctly

The HTTP code 429 “Too Many Requests” is a standard response used by servers to indicate that the client has exceeded the limit of requests allowed in a given time interval. This code, introduced in the HTTP/1.1 specification, is widely used in systems that implement security policies rate limiting to prevent overloading or abuse of server resources.

What does HTTP code 429 technically mean?

When a client (for example, an application using an API) sends too many requests in a short period of time, the server temporarily blocks further requests by returning code 429. The server's response may include:

• Header Retry-After: specifies the amount of time (in seconds or as a timestamp) the client should wait before retrying. This header is optional, but highly recommended to clearly communicate rate limiting rules to the client.
• Error message: a response body that explains the reason for the block or provides details about the restriction policies applied.

How to Handle HTTP Code 429 Correctly

1. Retry the request after the indicated interval
   When the server returns a 429 code with the header Retry-After, your application must meet the specified waiting period. This means:
   • Analyze the header Retry-After: read the value provided by the server to calculate the waiting interval.
   • Implement a waiting queue: pause the request until the indicated time expires, avoiding sending further requests that would be rejected.

   If the header Retry-After is not present, it is good practice to adopt a default delay (for example, 30 or 60 seconds) to ensure responsible and respectful behavior of the server resources.

2. Dynamically modulate throttling
   In response to a 429, your application should automatically adjust its request rate to meet the limits imposed by the server. This can be accomplished by:
   • Reducing the number of requests per second: dynamically adjusting the pace of requests to avoid further errors.
   • Exponential Backoff Algorithms: progressively increase the interval between successive requests. For example:
     • 1 second for the first attempt.
     • 2 seconds for the second attempt.
     • 4 seconds for the third attempt, and so on.
       This approach allows the server to recover resources and reduces the risk of continuous overloads.
3. Monitor and log 429 occurrences
   Integrating a logging system to track received 429 responses helps you identify problem patterns and optimize your application's behavior. For example:
   • Threshold Analysis: detect when and why limit exceedances occur.
   • Automatic alerts: send notifications to technical managers when the number of 429s exceeds a critical threshold, enabling rapid intervention.

Benefits of proper management

Proper handling of HTTP 429 code offers numerous benefits:

• Avoid server overload: respecting the imposed limits guarantees the stability and efficiency of the system.
• Improve user experience: Smooth, predictable communication between client and server reduces downtime and failures.
• Optimize operational efficiency: By dynamically adapting the behavior of your application, you can maximize resource usage without exceeding limits.

A well-designed application not only recognizes and responds to HTTP 429 codes, but uses this information as feedback to improve real-time request handling, resulting in greater reliability and overall system performance.

Conclusion

Addressing the issues of API abuse and server infrastructure limitations is not only possible, but can become an opportunity to improve the entire digital ecosystem, adopting targeted strategies and well-designed technical solutions. Implementing techniques such as dynamic throttling, HTTP response code honoring, and intelligent request limit management not only improves system stability but also optimizes overall performance by reducing downtime and overload issues. These approaches ensure responsible management of resources and a smooth, predictable user experience, which is essential for the success of modern e-commerce.

However, the key to truly excellent results lies in a synergic collaboration between developers and the hosting and systems department. Developers, knowing the potential and limits of the infrastructure, can design software solutions that respect the server's capabilities, avoiding excessive requests or critical inefficiencies. At the same time, systems engineers can provide valuable feedback on real performance and suggest configurations and optimizations that further improve the behavior of the applications.

This cooperation is not only technical, but strategic: allows you to anticipate problems, solve them with scalable approaches and guarantee a higher level of service to the end customer. The customer, who is at the center of the entire process, benefits from a stable, fast and reliable e-commerce, essential elements for user satisfaction and commercial success.

Ultimately, only a collaborative approach between developers and system administrators can transform the limitations of infrastructures into opportunities to create a more solid and rewarding ecosystem. It is this synergy that allows us to offer significant added value to the end customer, ensuring not only the well-being of e-commerce, but also its lasting success in an increasingly competitive market. Together, we can build an experience that not only meets, but exceeds expectations, enhancing every aspect of the infrastructure and the software that supports it.