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409 Conflict: What It Is And How To Fix It

When you try to view a website, you may see an error message displaying the “409 Conflict” which informs you that the server prevents your access. This situation highlights the data conflicts and may affect the user’s experience with the website.

This HTTP 409 Conflict post features the 409 error so we can learn its meaning, its causes & impacts, and find ways to solve the problem successfully.

Table of Contents

409 Conflict Status Code Meaning

409 Status Code indicates data conflicts between the request and the server, which cannot be successfully completed. The requested resource is unavailable, or the outcome of the requesting process would result in a conflict within the resource.

In simple words, if you upload an older version of this file than it already exists on the server, there will be data conflicts, and you may get an error message of 409 Conflict. If you don’t take action, it may cause your computer to freeze or crash, leading to malware infection.

HTTP 409 Conflict Status Code Error

The 409 Conflict is a client-side error that is under 4xx Status Response. To easily differentiate it, you can look at the 5 different encountered HTTP response Status Codes as followings:

  • 1xx Information Status Code: The request has been received, and the server is continuing the process.

  • 2xx Successful Status Code: The request is successful.

  • 3xx Redirection Status Code: Further action needs to be taken to complete the request.

  • 4xx Client Error Status Code: There was a client-side error.

  • 5xx Server Error Status Code: There was a server-side error.

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The Common Causes Of The 409 Conflict Error

The HTTP 409 Conflict Status Code demonstrates that the request cannot be comprehended owing to data conflicts between the current state of the target resource and the client’s request. There are some common causes that you should be aware of as followings:

  • Coexistent Modifications: The primary cause of the 409 error is when a number of multiple clients or processes access to change the same resource at the same time. The situation occurs when two or more attempt to update or change the resource’s state together, leading to data conflicts. As a result, the server may discover this conflict, and the 409 Status Code error message will display.

  • Versioning Conflicts: If a client’s request includes outdated or conflicting version information in the resource, there may be a versioning conflict. The server compares the client’s current version to that on the server and identifies a mismatch, resulting in 409 Conflict responses.

  • Issues Of Data Integrity: A 409 Conflict may occur if a client request breaches integrity requirements, or does not pass validation checks when trying to change the resource. This may happen if the data provided does not comply with the specified rules or limitations, such as specific key violations, incorrect information type mismatch, and referential integrity failure.

  • Rules Of Custom Business: The applications may have a custom business rule or domain-specific restrictions that can lead to conflict. These rules may determine the conditions or restrictions on a resource’s state and may lead to HTTP 409 Conflict error where requested amendments are not in accordance with those rules. Conflicts will arise when the client tries to make a reservation that has already been made available, such as in the case of a booking system that limits the number of reservations you can make once.

  • Optimistic Concurrency Control: This technique is used to control concurrent changes to resources. The HTTP 409 Conflict Status Code will arise if the server’s version differs from that of the client, indicating whether or not the resource has been modified since the client’s last retrieval.

  • Locking Mechanisms: This technique prevents concurrent changes to a resource. The HTTP 409 Conflict may occur if a client tries to modify a resource already locked by another client or process. In simple words, the requested operation cannot be completed owing to the locked resource.

Causes of the 409 Conflict error

The Common Impacts of The 409 Conflict Error

  • Impact User Experience: When a client receives a message about the 409 Conflict Status Code, which indicates that the requested action cannot be completed owing to conflicts with the resource’s current state. This can disrupt the user experience. Submission of forms, updating of data, performing transactions, etc., are the intended actions. The impact may cause frustration, confusion, and dissatisfaction for users.

  • Inconsistencies Of Data: As mentioned above, the 409 Conflict Status Code indicates the conflicts among data between the request of the client and one of the server’s current states. Thus, data inconsistency may occur if the problem cannot be resolved appropriately. Conflicting changes may result in mismatches, inconsistencies, or corruption of stored data which affect the integrity and reliability of the information provided by an application.

  • Increased Server Load: The server will have to deal with and solve the conflict when the HTTP 409 Conflict occurs. This may result in an increased workload on the server and resource consumption. To resolve the conflict, a server may require additional processing, conflict resolution mechanisms, and handling of errors. Recurrent or regular conflicts may negatively affect the server’s performance and scale.

  • Failures Of Transaction: The occurrence of a 409 Conflict may entail transaction failures in situations relating to transactions or critical operations. Conflicts may arise if several clients or processes attempt to change the same resources simultaneously, which can prevent the transaction from being completed successfully. This can result in financial consequences, disruption of business processes, and a loss of user confidence in the reliability of an application.

  • Delayed and Failed Updates: The HTTP 409 Conflict error may result in delays and the failure to update available resources. If there are conflicts, the requested modifications may not be applied until they have been resolved. Therefore, it may take a while to update the resource, leading to errors or obsolete information being made available to users. Conflicts may persist or continue to exist in some cases, leaving updates unable to be updated consistently until they have been resolved.

  • Influence on APIs and Integrations: The flow of data and the interaction between different services can be disrupted if 409 Conflict occurs in relation to API or integration with external systems. This can cause cascade problems and disruptions in service, affecting the functionality and reliability of dependent systems.

  • Negative User Perception: The reputation of an application or service may be damaged by frequent or unresolved conflicts 409 Conflicts error. The website can be regarded as unreliable, unstable, and inadequately maintained. Consequently, users may seek alternative solutions or platforms if they have negative experiences with the conflicts, leading to fewer users.

  • Impact On SEO: If the 409 error occurs frequently and hurts the usability or accessibility of your website or web app, it can be considered potentially detrimental to the SEO. Consequently, problems may arise that can harm the user’s experience, such as defective links, lost or incorrect information, and other issues. If the problem continues to persist, it may result in decreased user engagement and eventually lead to a negative effect on SEO

Impacts of the 409 Conflict error

Distinguish 409 Conflict From Other Status Codes

In the 4xx Status Response category, all errors are issues with client requests but serve different purposes. For easily understandable, you can refer to the comparison below to differentiate 409 Conflict from other Status Codes:

Differentiate The HTTP 409 Conflict And The 400 Bad Request

If there is a conflict between client requests and the current resource state, in many cases related to concurrent updating or versioning conflicts, the 409 Conflict Status Code will be used.

Meanwhile, if the server cannot understand or respond to a client request because of incorrect syntax and invalid parameters, the HTTP 400 Bad Request Status Code will be applied.

  • 409 Conflict: The Status Code indicates that the client’s request is not being fulfilled owing to an issue with the current state of the resource on the server. It is most frequently caused by multiple clients or processes trying to modify the same resource at the same time, or when versions are conflicting.

  • 400 Bad Request: The Status Code indicates a server cannot understand or process the client’s request since it contains incorrect syntax and no required parameters. The issue typically arises due to an error in a request’s structure and content, such as missing or incorrectly formatted headers, instructionally garbled JSON data, or methods not supported by the application.

Differentiate The HTTP 409 Conflict And The 412 Precondition Failed

The HTTP 409 Conflict Status Code indicates a conflict between the client’s request and the resource’s current state on the server, and the conflict related to the resource status is identified in the 409 error.

By contrast, the HTTP 412 Precondition Failed Status Code indicates that the server cannot fulfill the request since the preconditions determined in the request headers are not encountered. In addition, the 412 error is focused on conditions imposed by the client for a server’s operation.

  • 409 Conflict: The 409 Status Code demonstrates data conflicts between the client’s request and the state of the resource on the server. This usually happens when several clients or processes try to change the same resource altogether, or there is a versioning conflict. However, the server determines the conflict but does not provide any particular details on its nature in response.

  • 412 Precondition Failed: This Status Code indicates that the server does not fulfill the client’s request since the preconditions determined in the client’s request headers cannot be fulfilled. The conditions set by the client for the server to perform the requested operation are preconditions. You may receive a message of 412 Status Code if the server finds that the preconditions are not met. The conditions such as ‘Etag’, ‘If-Match’, or ‘Un-Modified Headers Since’ can be included.

How To Resolve The 409 Conflict: 7 Ways To Fix

There are several ways in which clients can resolve a dispute if they encounter such a 409 Conflict Status Code error. Possible solutions are as follows:

Understand the Conflict

Information about the cause of the conflict should be provided in an error message sent with a 409 Status Code. The client should look at the message to ascertain why the conflict occurred.

Examine the error messages, server logs, and any pertinent information given to obtain a detailed view of the nature of the conflict. Determine the nature of the conflict, whether it is a simultaneous modification, versioning conflict, or data integrity issue.

Check Requested URL

Sometimes, the URL may need to be entered on your own; check if it’s spelled correctly. You may receive a Status Code 409 when the web address is incorrect.

Send The Request Again

After considering the conflict, one option could be a restatement of the request. The server’s response, including other information or guidance on resolving conflicts, should be reviewed by clients before retrying. To resolve the conflict, clients may modify the request parameters or payload and then send it again.

Contact and Discuss With Other Parties

The client may communicate with other parties involved in coordinating their actions under scenarios involving collaborative systems or concurrent modifications. The client can reach an agreement with another user or system on how to solve a conflict and prevent the future one through discussions of the changes.

Contact and discuss the 409 Conflict error with other parties

Merge The Versions’ Changes

You can try reconciling the conflicting changes when a 409 Conflict error arises due to concurrent modifications. That process aims to retrieve the latest version of the resource, analyze differences within incompatible changes and use a merge strategy to combine this change with another. After that, the merged version will be sent as an update request to the server.

Use Conditional Requests

To keep the resource updated on the most recent version, you can use conditional requests that contain relevant headers such as E-tag or If-Match. The client can indicate when their update should occur by including these headers in the request to ensure that the resource’s state corresponds to what they expect it to be. Moreover, you may also retrieve the latest version and try to update it if they do not comply with these conditions.

Review Versioning and The Strategies To Resolve The Conflict

You should review the server’s versioning mechanisms or conflict resolution strategies when conflicts arise due to a modification or custom business rules. In order to avoid future conflict, the client may be able to adapt requests and behavior accordingly by understanding the server’s rules and guidelines.

Try a Different Browser

You can also get a 409 Status Code if you have any problems with your web browser. If so, you can switch to another browser. To access a website, you just need to enter its address in another browser and press the “Enter” key.


The 409 Conflict error is an HTTP Status Code under the 4xx Status Response category that indicates the uncompleted request due to data conflicts between the client’s request and the server.

To maintain data integrity and ensure that clients and servers communicate consistently, it is essential to know the causes and impacts of the 409 Conflict error and implement adequate solutions.

You can effectively deal with conflicts and improve the user experience by providing informative error reports, automatically retry mechanisms, using conditional requests, and implementing conflict resolution strategies. In order to resolve conflicts effectively, it is essential to adopt these practices, which will allow seamless interaction with web resources.

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Hello, I'm the Chief Technology Officer of Mageplaza, and I am thrilled to share my story with you. My deep love and passion for technology have fueled my journey as a professional coder and an ultra-marathon runner. Over the past decade, I have accumulated extensive experience and honed my expertise in PHP development.
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