Building a reliable AI bank statement converter: why independent validation beats better prompts
Original: I built an AI-first bank statement converter. The one rule that stopped it lying to me.
Short summary
The author built StatementDecoder, an AI-first bank statement converter, and discovered that the real challenge wasn't extraction but verification. Feeding statements to an LLM for structured JSON worked well but silently failed on individual rows. The fix was an independent validation layer using bank statements' built-in consistency checks (opening balance + transactions = closing balance) rather than trusting the LLM to self-verify. Edge cases with Wise, Revolut, UK, and Australian bank formats taught the broader lesson: AI doesn't need to be perfect, just independently verifiable.
- •LLM-based bank statement extraction works well but silently fails on individual rows
- •Independent validation using balance reconciliation catches errors before user export
- •Key insight: AI output needs independent verification, not self-verification
Generated with AI, which can make mistakes.
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