The Hidden Costs of AI APIs Beyond the Listed Token Price

A developer who has built with AI APIs for two years reports a $1,400 weekly bill that far exceeded the advertised per-token rate. Much of the expense came from tokens being counted differently than expected, such as entire email threads and signatures being billed as input. Re-sending large amounts of unchanged context on every request also inflated costs, with one script using roughly 18 times more than necessary. Rate limits proved unpredictable and, when combined with naive retry logic, turned a short batch job into a multi-hour process. The author also found that data transfer charges between services in the same region added unexpected expenses.