Mathura has a very long Jain history. In ancient times it was one of the early centers where Jains worshiped and where Jain stupas and ayagapatras (tablet votives) were built, showing a well-established Jain sangh in the city. The famous Kankali Tila find (a Jain stupa and related tablets) near Mathura dates to the early centuries CE and indicates a thriving Jain presence and patronage in the area. This points to a community that was active in religious and social life from a very early period. ( en.wikipedia.org)

As for which occupations Jain followers tended to have in Mathura, traditional Jain communities across many regions were often linked to commerce and skilled crafts. Specifically in historical Mathura, Jains were known to be involved in mercantile activities, trade and money-related professions, as well as crafts and artisan work that supported temple and stupa activities and the broader Jain sangh. This mercantile and artisanal presence reflects a common pattern in many Jain communities where lay Jains contributed through business, trade, craftsmanship and related services. However, exact occupational breakdowns by caste or neighborhood for ancient Mathura are not recorded in a single comprehensive source; the available archaeological and textual materials mainly attest to the overall prominence of Jains in religious and social life of the city. ( en.wikipedia.org)

In short, Mathura was an important Jain center long ago, evidenced by stupas and votive tablets from the period, and the Jain lay community there historically included merchants, traders and craftspeople who supported and sustained Jain institutions. If you’d like, I can share more about specific Jain sites in Mathura (like the Kankali Tila stupa) or explain how Digambara and Śvetāmbara traditions are represented in Mathura, with references.