Ask API. GET https://whichemulator.wtf/ask answers questions from the same data as this page, and it is the only place the setup steps are published. It takes the question as q and, optionally, this page's path as page, and returns JSON with answer, sources and follow_ups, or Markdown with Accept: text/markdown. No key needed.

curl -G 'https://whichemulator.wtf/ask' --data-urlencode 'q=Which WonderSwan emulator should I use on a Mac?' --data-urlencode 'page=/wonderswan/'

Questions it answers:

Guide: /skill.md. This page as Markdown: /wonderswan.md

Best WonderSwan emulator: Mesen, the Gold Cartridge pick

Bandai WonderSwan / WonderSwan Color, Bandai, 1999. Japan-only, co-designed by Gunpei Yokoi's Koto Laboratory.

Recommended: Mesen

whichemulator.wtf calls its recommendation for each system the Gold Cartridge pick. For the WonderSwan, the Gold Cartridge pick is Mesen.

Mesen added WonderSwan and WonderSwan Color in 2025, and its accuracy is now on a level with ares and ahead of Mednafen. It handles vertical games well, runs without a boot ROM, and comes with a proper debugger. If you use Mesen for anything else, this is a free win.

Runs on Windows · Mac · Linux. Open source. Download: https://www.mesen.ca

Boot ROM optional: Games run without one. If you want the original boot screen in Mesen, dump the boot ROM from your own WonderSwan.

Alternatives

ares (Windows · Mac · Linux, open source): Just as accurate, with near-complete compatibility. Pick it if you already use ares for other systems.
Mednafen (Windows · Mac · Linux, open source): Older and a step behind on accuracy, but runs the library fine and is the basis of the main RetroArch core. Command line only.

RetroArch cores

Beetle Cygne: Mednafen's WonderSwan code. Solid, no BIOS needed.
Mesen: The MesenCE core also covers WonderSwan and Color.

Neither core needs a BIOS.

Hardware

Colours: 8 of 16 greys / 241 of 4,096 (Color)
Resolution: 224×144
Sound: 4-channel wavetable
Models: WonderSwan, Color, SwanCrystal
Library: 109 mono games, plus Color titles

Notes

Why Mesen

For a long time WonderSwan emulation meant Mednafen or old Windows-only programs. ares and then Mesen raised the bar, and Mesen is the easier of the two to use: load a game, pick horizontal or vertical, play.

The original Mesen repository was archived in 2026 and work continues as Mesen Community Edition. mesen.ca links to the new builds.

Japan-only, mostly

Bandai only sold the WonderSwan in Japan, so most of the library is in Japanese. Fan translations exist for a fair number of the better-known games, so check before you assume something is unplayable.

Support the developers

Reference: WEM-WONDERSWAN-H683