Show HN: Marginal – See which customers and features drive your AI API costs

Show HN: Marginal – See which customers and features drive your AI API costs Demo account (shared, please be nice): https://marginalhq.com/login - email jithinlalk25+demo@gmail.com, password marginal-demo-2026. It's a seeded workspace for a fictional company; poke around Overview/Insights/Explorer. Or sign up and send real events.