Costa Rica Developer Says Anthropic Console Charged $504 Instead of $5.04 After Decimal Input Bug

The post, dated Oct. 16, 2026, described the sequence. The platform prompted him for a payment. Because he is in a Spanish-speaking region where localized systems and keyboards handle dots and commas differently, he typed 5.04. He said the system neither rejected nor converted the input. Instead, it silently removed the decimal internally and instantly charged $504.00 USD. There was no confirmation modal or review screen summarizing the final amount before processing, he said, making it a single-click, instantaneous overcharge.

He said he filed an official complaint on the same day, minutes after the charge. He was not met by a human, he said, but was blocked by an automated support bot. The bot repeatedly denied the refund, he wrote, closing the ticket by citing generic policies without a human ever reviewing the fact that the overcharge was caused by a technical bug in the platform.

He also said he has initiated a chargeback with his bank in Costa Rica. Banking processes there are slow and can take up to 120 days to resolve, he said. In the meantime, the $504.00 has already been deducted and charged to his credit card statement, forcing him to pay for the error out of pocket now.

The post anticipated skepticism. He argued that users are not the QA team. In financial software, he said, a system is never supposed to guess or automatically manipulate a numerical input without explicit validation. If an input is ambiguous because of locale differences, he wrote, the application must reject it or ask for clarification rather than execute a 100x overcharge.

He warned that the problem could scale. The $504.00 charge is an unfair burden for independent developers, he said, but because the payment pipeline lacks a confirmation screen and basic input sanitization, the same bug could affect someone typing 50.00 and result in an instant charge of $5,000.00 or more. He called it a systemic financial risk.

He addressed what he described as the chargeback illusion. He acknowledged that he has already initiated a chargeback, but said delays in the banking process leave him covering Anthropic's engineering mistake. As developers, we build systems that process people's money, he wrote. Omitting a confirmation screen on a financial transaction, failing to sanitize localized numerical inputs, and then hiding behind unyielding AI support bots to keep money that does not belong to the company is unacceptable, he said.

He asked anyone from Anthropic's billing or engineering team to look into the bug and review his case. He said it is a critical flaw that is actively harming international developers who are trying to build on the ecosystem. He ended the post with the phrase Pura vida. The Hacker News post had 27 points and 2 comments at the time of the material, which did not include a response from Anthropic or independent documentation of the charge.