js65 - Advanced 6502 assembler with patching support based on ca65 syntax

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Summary

js65 is an advanced 6502 assembler written in TypeScript, based on ca65 syntax, designed to simplify ROM patching for NES homebrew, romhacks, and randomizers.

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Cached at: 09/12/26, 08:41 PM

# js65 Source: [https://jsnesx.github.io/js65/](https://jsnesx.github.io/js65/) Advanced 6502 assembler with patching support based on`ca65`syntax [Get Started](https://jsnesx.github.io/js65/docs)[Download Now](https://jsnesx.github.io/js65/download) ## What is`js65`[https://jsnesx.github.io/js65/#what-is-js65](https://jsnesx.github.io/js65/#what-is-js65) Written in TypeScript,`js65`intends to be an almost fully compatible`ca65`\-style assembler, but with many new features to make patching roms a breeze\. Whether you are making a homebrew NES game, a romhack, or a randomizer,`js65`’s power additions on top of the baseline`ca65`features makes your life easier\. --- [For Homebrew Auto pack banks with cross bank placement](https://jsnesx.github.io/js65/#)[For Romhacks Assembler controlled linker placements](https://jsnesx.github.io/js65/#)[For Romhacks Free space tracking for squeezing patches everywhere possible](https://jsnesx.github.io/js65/#)[For Randomizers Use as a library to programatically configure the output](https://jsnesx.github.io/js65/#)

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