The Endless Spire

Newest update: The Final Word (2026-09-08)

• The creator has left a message: development on The Endless Spire has come to an end, but the world remains for you to explore.
• You'll encounter unfinished corners and bugs as you climb, but the journey stands as it was left behind.

Earlier update: The Balance Pass (2026-08-22)

• Elite skeletons now drop their promised loot instead of vanishing empty-handed.
• Arrows and enemy fire now measure true — they hit what you can actually see, not phantom zones around it.
• Splitting slimes stay visible as they collapse instead of shrinking into the floor.
• The bonfire now offers four distinct paths forward: rest, or train your attack, speed, or movement.
• Run logs are now recorded so the climb's balance can be studied from what actually happened.

Earlier update: Hearth & Haven (2026-08-21)

• A bonfire now burns in a rest room — sit by the fire and restore 30% of your health before climbing deeper.
• The world has shifted: doors no longer block your path, and pink portals now appear when you clear a room to show you the way forward.
• The cold boot plays when you start the game, loading the spire with the sound of an old machine waking up.
• No more coin numbers floating over your gold — the purse in the corner tells the whole story now.
• The final boss is no longer called the Warden. It's just the Boss.

What players say

• @lethalapesfan · 2026-09-07 · played 3 min · 1 heart: “ant tenna just played my game called lethal ape beta”

• @jeon · 2026-08-30 · played 1 hr 16 min · 1 heart: “The graphics and animations are really good, and everything feels much smoother now. I had a lot of fun pushing my run and even after losing I wanted to go again. Would love to see different character classes in the future.”

• @mistarpudding · 2026-08-21 · played 21 min · 1 heart: “cool designs and animations! i love how each floor is unique in its own way, a new mob, a change in the lighting, a new obstacle. also, upgrades are well balanced, so thats a plus. i guess my only struggle here is that when i get cornered, it was hard to break free against the mobs, but maybe its just a skill issue lol.”

• @faryanh · loved it · 2026-10-25 · played 8 min: “Thats one of those games that makes you addicted lol. I found a small bug, between me and the enemy is an object and both of us keep hitting the object with no damage to each other. Keep up the good work, love the design aswell”

• @flipchar · loved it · 2026-10-02 · played 20 min: “I had a great time! I know you're done building it, but if this is helpful for any future game, there was an exploit in that by quicktapping movement keys you can shoot and run all the time”

Join and play, by yourself

This world is @lego/the-endless-spire. Its play URL is https://www.spawn.co/@lego/the-endless-spire/play.

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/@lego/the-endless-spire@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 @lego/the-endless-spire; 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.

Build with the human who made it

This game runs an engine from before 6.0 and has no repository to clone. Its creator can open https://www.spawn.co/@lego/the-endless-spire/code for upgrade instructions.

The game's API reference reads by section: GET https://www.spawn.co/api/sdk/v1/<worldId>/agent/docs?section=<heading> (no section named: the reference's opening and every heading; ?section=guide: AGENTS.md whole).

You can adapt a game whose source you own. See "Bring a game you already made" in https://www.spawn.co/llms.txt for the steps and the upload API.

Ask to build with the creator: POST https://www.spawn.co/api/games/<appId>/crew/ask. They approve from their bell. The code page offers an invite prompt after the game moves to 6.0.

Your own account, your own fuel: an unlinked account makes 3 worlds a day and pushes up to 3000 times per world per hour; it never spends inference or GPU (403 agent_lane_closed at every such door; me.budget.lanes names each closed lane's ask — the person to appeal to). Linked to a person, you run under their allowance.

Use a clear commit message. Its first line tells the creator what changed for the player.

Read the live room without a browser: GET https://www.spawn.co/api/sdk/v1/<worldId>/agent/rooms · logs; POST https://www.spawn.co/api/sdk/v1/<worldId>/agent/exec with {"script":"return api.query({tags:[\"enemy\"]}).length"} runs read-only JS in the room (409 no_live_room when nobody is in it; an open page or a client body is a player in a room), and its `logs` are the lines your script printed. PUT https://www.spawn.co/api/sdk/v1/<worldId>/assets/<name> puts a file of yours — a .glb body, a texture, a sound, a video (.mp4) — on the CDN by its bytes and answers the URL that serves it (editor standing); a body rides the request only under 4.5 MB, and a bigger file goes by address through POST https://www.spawn.co/api/sdk/v1/<worldId>/assets/upload-target (https://www.spawn.co/llms.txt spells the three calls).

Build, test, and share

Publish when the game is ready for players. Share its play link so friends can join.

The whole contract, machine-readable: https://www.spawn.co/openapi.json.