Recently, I completed the development of an Opencart-based online store for a client. The project reached its conclusion, payment was received, and all functionalities are operational, leaving both parties satisfied. However, the client recently engaged a specialized store promotion expert, also known as an SEO specialist, requiring my assistance once again. It appears that the language changes on the website, facilitated by regular POST requests and cookies, only allow indexing of pages in the primary language. Consequently, this approach is unfavorable for search engine optimization (SEO).

Fortunately, I assured them that there is a viable solution. I proposed implementing a language format in the URL, such as "somesite.fr/en/index.php," while subtly indicating that it would come with additional costs. After successfully executing this solution, the desired outcome was achieved, meeting their expectations.

However, the client is hesitant to pay for this extra work, claiming it was already included in the initial agreement. As the developer, I firmly believe that since this aspect was not discussed during the ordering process, it should be considered as supplementary work and billed separately. It is crucial to note that the client's representative may not have foreseen the need for this feature.

Regrettably, we did not formalize our agreement through written dоcumentation.
How can I protect myself from such situations and how to most tactfully request money from the contractor for additional work?

In situations like these, it is important to have clear communication and agreements in place to avoid misunderstandings. Here are a few steps you can take to protect yourself and tactfully request payment for additional work:

1. dоcument the Scope: Clearly define the scope of work at the beginning of the project. This includes specifying the features, functionalities, and any potential additional work that may arise. It is crucial to have this dоcumented in writing, such as in a contract or statement of work.

2. Maintain Open Communication: Throughout the project, keep open lines of communication with your client. Regularly update them on the progress and any changes that may impact the scope of work. This way, they are aware of the additional effort required for certain tasks.

3. Communicate Additional Work: If new requirements or features arise during the project that go beyond the initial scope, promptly inform the client about the additional work and discuss how it will affect the timeline and cost. Providing clear explanations and justifications for the extra effort will help the client understand the need for additional payment.

4. Revisit the Agreement: If the client claims that the additional work was already included in the initial agreement, respectfully revisit the agreement and emphasize that it did not explicitly cover the specific task. Without written dоcumentation specifying the inclusion of the feature, it is reasonable to consider it as supplementary work.

5. Invoice for Additional Work: Create a separate invoice for the additional work, clearly detailing the tasks performed, the time invested, and the corresponding charges. Present the invoice politely and professionally, explaining the reasons for the additional cost and referring back to the discussions and agreements made throughout the project.

In addition to the steps mentioned earlier, here are a few more actions you can take to protect yourself and handle the situation tactfully:

1. Provide Evidence: If you have any dоcumentation or evidence that supports your claim for additional work and payment, share it with the client. This could include emails, chat logs, or any other correspondence where the scope of work was discussed or changes were requested.

2. Offer a Compromise: If the client is hesitant to pay for the additional work, consider offering a compromise. This could involve negotiating a reduced fee or offering to include the additional work as a part of future projects or maintenance tasks. Finding a middle ground can help maintain the working relationship while addressing the financial aspect.

3. Seek Legal Advice: If the client still refuses to pay for the additional work and you believe you are entitled to compensation, you may want to seek legal advice from a professional. They can help review the details of your situation and guide you on the best course of action based on applicable laws and regulations.

4. Learn from the Experience: Use this situation as a learning opportunity to improve your processes and protect yourself in future projects. Consider implementing written contracts or agreements for all projects, even if they are small, to ensure clarity and avoid any misunderstandings.

You are not a Seo specialist, so I believe it was fair to ask for an additional fee since this condition was not clearly stated from the beginning.

The customer agreed to pay extra but did not actually pay the extra fee.

In situations like this, it is important to request an advance payment. It is crucial to explain that the difference in implementation was not a mistake on your part, but rather two different interpretations of the same concept. Since there was no specific agreement on which option was required, the decision was made based on discretion.

You will not receive any payment in this specific case. If there are no dоcuments, there are no payment obligations.

To protect yourself, it is important to include in the contract for creating a website the number of hours that will be dedicated to additional site improvements if there is no clear Technical Order Request (TOR). For example, I typically allocate 70 hours for unspecified adjustments in the TOR. Clients usually feel comfortable signing such a contract because they understand that 70 hours is a substantial amount.

To avoid working for free in the future, it is crucial not to neglect bureaucratic tasks such as writing technical assignments, briefs, acceptance certificates, and contracts. While a contract does not offer a 100% guarantee, it is still better than relying solely on trust.

Regarding tact, it is not tactless to request payment if there was no prior discussion about changing the URL's cleanliness during the website creation process. The additional work required should be compensated for. Calculate the labor hours, multiply them by your hourly rate, and send an invoice to the client.

However, in this situation, it may be difficult to obtain payment. Resorting to unfavorable actions might be necessary, but considering the amount at stake, it is probably not worth behaving unprofessionally. It is better to maintain a positive attitude towards the client and communicate that you do not intend to work for free in the future.

The exact conditions under which additional payment is merited should be set out in the terms of the contract, however, generally, the contractor must be able to prove the following: The contract sum does not include the additional work. There was an express or implied promise to compensate the contractor for the work.

To shield your codebase from such scope creep, always insist on detailed wireframes, sprints, and version control in Git repos upfront.
For tactful billing, remind them via email about the extra middleware for multilingual URL routing, caching layers, and API endpoints not in the original backlog, proposing a fair patch fee. Use tools like Jira for tracking, and escrow payments to avoid disputes.