Aaron Ellman
Python backend dev, shipped SaaS billing & automation.
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Bank Statement Analyser: Turns raw PDF bank statements into structured spending data
Built a CLI tool that parses FNB PDF bank statements, extracts every transaction, and stores them in a local SQLite database, automatically categorizing spending across 50+ built-in merchant mappings so patterns are visible by category and month instead of buried in a PDF. Implemented SHA-256 file hashing so re-imported statements are automatically skipped rather than duplicated.
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Market Simulator: Simulated financial exchange with a full matching engine
Built a simulated exchange to explore how real trading systems work under the hood. A limit order book with price-time priority matching, supporting multiple instruments each with their own independent book. Implemented partial fill support in the matching engine and a configurable bot framework to stress-test it at scale, with PostgreSQL persisting every trade.
Exposed the whole thing through a REST API (FastAPI) for placing and cancelling orders, querying the live order book, and retrieving trade history; designed and tested like a real production system, not a script.
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Schedufast: Automated timetable-to-calendar sync for students
Students lose hours each term manually copying class schedules into their calendars. Schedufast parses a student's timetable and automatically populates their Google Calendar, cutting a task that used to take up to two hours down to a few clicks.
Built as a live SaaS product with subscription billing via the Paystack SDK, including webhook handling for real-time payment events. Handled the full stack: parsing logic, Google Calendar API integration, and a production billing pipeline serving real paying users.
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