Few high-leverage plays for a dev looking to build income streams:
1. **Micro-SaaS for a niche you know** - Don't build generic tools. Find a specific industry pain point (real estate agents, dentists, local gyms) and solve one thing really well. Charge monthly. The niche players mentioned here like wedding sites are valid - but pick something you won't hate working on for years.
2. **Internal tools for SMBs** - Small businesses constantly need custom dashboards, inventory trackers, booking systems. Not sexy but recurring revenue. One local business paying you /month for maintenance is worth more than chasing viral traffic.
3. **Programmatic SEO plays** - As a dev you can build sites that auto-generate pages at scale. Think directory sites, comparison tools, aggregators. Traffic compounds if you pick the right keywords. Monetize with ads or affiliate.
4. **Browser extensions** - Underrated. Low competition, easy to rank in Chrome store, can charge subscriptions or do freemium with ads. Find an annoying workflow in any SaaS tool and fix it.
The wedding/event space someone mentioned is solid but crowded. I'd look at B2B niches where people actually pay for software - not consumer stuff where everyone expects free.