Looking for Part-Time C#/.NET Web Developer - Long-Term Retainer

We are looking for an experienced WordPress/web developer to provide ongoing technical support for an established online marketplace business and a network of approximately 15–25 dealer websites. The primary responsibility will be maintaining and troubleshooting relatively simple WordPress websites used by our dealers. These sites receive inventory data from our main platform and/or third-party inventory providers, so we need someone who is comfortable working beyond the WordPress admin panel and can diagnose technical issues involving data feeds and integrations. A major part of the role will be troubleshooting inventory feed problems. Our inventory may come from third-party systems and feeds using APIs, XML, JSON, CSV, or similar methods. When inventory stops updating, listings are missing, images are incorrect, or data is not mapping properly, we need someone who can investigate the issue, determine where the failure is occurring, and either fix it or clearly identify the problem for escalation. The WordPress work itself will include routine maintenance, plugin and theme updates, backups, security, hosting/DNS troubleshooting, minor layout changes, content updates, forms, basic performance optimization, and occasional creation or modification of dealer websites. We would also like this person to have solid front-end development skills, particularly HTML, CSS and JavaScript. Experience with PHP and WordPress development is important. Some graphic/design ability for basic website graphics, banners and similar marketing assets would be helpful but is not the primary focus of the position. Our primary marketplace is a custom application rather than WordPress. Most of its backend is C#, with Razor Pages and vanilla JavaScript on the frontend. We already have a developer responsible for the more complex application development. You do NOT need to be our primary C#/.NET developer, but familiarity with .NET/C#, Razor, SQL, APIs, or general full-stack development would be a significant advantage. Ideally, you should be technically capable enough to investigate an issue, understand which system is causing it, and communicate effectively with our primary developer when something needs to be escalated. We are specifically looking for a technically strong, versatile developer rather than primarily a WordPress designer. Troubleshooting ability is extremely important. We want someone who is comfortable opening logs, inspecting API responses, examining feed data, debugging integrations, and figuring out why something isn't working instead of simply saying that the problem is outside WordPress. This is intended to be an ongoing relationship rather than a one-time project. We anticipate approximately 10–20 hours of work per month, although workload may vary. We would prefer to develop a long-term relationship with one developer who becomes familiar with our websites, inventory systems and business. We're a small family company, that deals in the equine/western world. The core values of our business and ease of someone to work with are worth the extra cost to us. Important skills: WordPress, PHP, HTML/CSS, JavaScript, REST APIs, XML/JSON/CSV data feeds, integration troubleshooting, hosting/DNS, website maintenance and debugging. Experience with C#, .NET, Razor Pages, SQL, Git/GitHub, Cloudflare or inventory/e-commerce/marketplace systems is a plus. When responding, please tell us about your experience troubleshooting API or inventory/data-feed integrations, not just building WordPress websites. Examples of situations where you diagnosed and fixed a third-party integration problem would be particularly helpful.