HeroForge was a community-built electronic character sheet for Dungeons & Dragons 3.5 Edition. The product received regular updates, particularly as new errata, updates, and source books were released for the game. The product was released as an XLS and, later, XLSX workbook for Microsoft Excel. Versions were also released for Open Office. Although the product never supported every source book released, it supported most material dealing with character creation. Numerous calculations and programmatic operations were used to heavily automate character creation and spreadsheet calculations.
Because the spreadsheet required extensive data derived from the copyrighted books it was considered by some to be controversial for infringement of intellectual property. The developers and promoters believed the product was compliant with the open game license, however.
Some effort was made to convert the product to the D&D 4th Edition, but several of the key developers departed the community to work on a commercial replacement project. The final version released under the community development effort was 188.8.131.52.