An organiser could sell through a dedicated website or app, using its own branding and customer journey. That also means deciding how people discover events and where they go for support; a private sales page does not automatically provide a marketplace audience.
The essential workflow includes capacity, checkout, payment confirmation, ticket delivery and admission checks. Before development, review whether an existing booking service with suitable branding options would meet the need. Bespoke development is most relevant where the workflow requires something those options cannot provide.
Pilot a straightforward event and measure completed purchases and support issues. Test refunds and reissued tickets before launch. Compare the full operating responsibilities, rather than assuming that removing a marketplace removes every transaction cost or administrative task.
Related reading: Events Business Software Solutions.