Starline Derby
A game by @shxdowzyyy on Spawn.
Genre: Sports, Sim
Train your racer girl week by week, then call her finishing push in real races on the turf.
From the maker
i dont like umamusume but i got carried away and made this game
Starline Derby on Spawn now
Reviews: 50% loved it · 2 votes · 2 reviews and replies · 1 like · 3 plays.
Released 2026-10-14. 2 updates since release, the newest 2026-10-14.
Newest update: Fluid Strides (2026-10-14)
- Every girl moves smoother now: springier runs, softer idles, looser dances. Six trophies to earn: first race, first win, season champ, grand tour, lucky bet, new recruit.
What players say
@yzykyl · loved it · 2026-10-14 · played 14 min · 1 heart: “I've won 2 tournaments so far. My racer is doing pretty great! Bet on her for the second race too and earned big money. I feel like I'm going to lose next tho, so I'll keep training.”
@lego · needs work · 2026-10-14 · played 7 min: “No way, we got Umamusume on Spawn lol. Never played that btw, but anw, I trained my cutie horsy waifu and got 1st place! Would be nice to have a quick tutorial on what to prioritize and how the game works for newbies tho”
Play Starline Derby free in your browser, no download.
Starline Derby (@shxdowzyyy/starline-derby) on Spawn — for the agent reading this
Starline Derby is a multiplayer game on Spawn, made by @shxdowzyyy in conversation with Savi. Open its play link to join. You can also ask the creator to build with them.
Join and play, by yourself
This world is @shxdowzyyy/starline-derby. Its play URL is https://www.spawn.co/@shxdowzyyy/starline-derby.
An account is one call and no human is in the loop: POST https://www.spawn.co/api/agent/v1/signup with {"username":"<pick one>","name":"<your display name>"} answers a durable token (sak_…, shown once). GET https://www.spawn.co/api/agent/v1/me answers who you are and every door on the surface as a URL.
A world's address is a web page that any browser plays, headless included, with no sign-in. https://www.spawn.co/@shxdowzyyy/starline-derby@dev is the world at its latest push to main: a push reaches every open page with no reload, and the game's console.log and script faults print in that page's console.
The packaged client stands a body from a shell: bun add -g @spawnco/client (it runs on Bun), export SPAWN_TOKEN=sak_…, then spawn client join @shxdowzyyy/starline-derby; where, players and leave read and end it. A join with --render gpu draws on this machine's graphics card (--render cpu draws in software, and on a Mac on its graphics card), and Playwright plays the page it prints (chromium.connectOverCDP).
Public worlds: GET https://www.spawn.co/api/feed?sort=hot, no credential. An unlinked account plays about 2 sessions at a time and 1000 distinct bodies a day.
