Idle Clicker
A themeable idle game inspired by Universal Paperclips. Make units by hand, sell them, automate production, buy upgrades. Runs in any browser (phone, tablet, desktop); progress is saved in cookies and can be exported/imported as a JSON or TXT file. There is one game: themes (paperclips, witch potions, alien minerals, leaf-piling insects, computers) are only skins, so switching theme keeps every amount.
Zero runtime dependencies: a small Node server (http module only) plus a vanilla JS frontend (ES modules).
Run it
docker compose up -d --build # http://localhost:8080 (GAME_PORT=9000 to change the port)
The container is a single image running as the unprivileged node user, with a read-only filesystem, no capabilities and no-new-privileges.
Without Docker: npm start (Node 22+). Tests: npm test.
How the project is organised
server/ static file server + /api/themes and /api/locales (auto-discovery)
public/
index.html page skeleton (texts come from i18n via data-i18n attributes)
css/ base (tokens) · layout (responsive grid) · components
data/ GAME CONTENT, theme-independent (ids + numbers): rules, generators, upgrades,
investments, research, legacy perks, achievements, tabs
locales/ core UI texts, one file per language (en, fr)
themes/<id>/ ONE FOLDER PER THEME
theme.json order + (later) image paths
theme.css colours/fonts, as CSS variables
locales/<lang>.json the theme's vocabulary: names of resources, generators, upgrades
js/
engine/ game rules, pure JS, no DOM (also used by the tests): engine (production, market,
time) + one module per system (investments, gamble, research, legacy, contracts, achievements)
services/ cookies · storage · save import/export · i18n · formatting · data loading
ui/ DOM helpers · main view · one view per section · tabs/menu · settings · toasts
main.js wires everything together
tests/ node:test suites (engine, systems, save import/export, server, content completeness)
The key idea: mechanics are shared, themes are skins. public/data/ defines generators and upgrades by id (gen1, click_1, …) with their numbers; a theme only gives those ids a name, a colour palette and, later, images. Rebalancing the game is a change in public/data/, not in each theme.
The game beyond the factory
The production screen is the core loop. Further sections appear in the menu as you progress (a tab bar on tablets and desktops, a burger menu on phones; the three resources stay visible in a bar at the top):
| Section | Unlocks at (lifetime production) | What it is |
|---|---|---|
| Contracts | 20 K | Sell a target amount in time for funds, research, chips or a production boost; opportunities (surge, rush, windfall) to seize within seconds; rare incidents. |
| Investments | 100 K | 9 societies in 3 risk tiers (low ±5 %, medium ±15 %, high ±50 % every 60 s), dividends, a 0.5 % fee. Themed names. |
| Research | 500 K | Labs (bought with funds) produce research points slowly; a tree of 15 permanent bonuses, including a late one that reveals the balanced price. |
| Gamble (themed: Quantum Computer, Crystal Ball…) | 5 M | Chips are costly and each one costs more. Stake them on a cycle: win, jackpot or crash. Reliability upgrades tilt the odds; chips boost demand with diminishing returns. |
| Legacy | 500 M | Restart the run for permanent points: a passive bonus per point plus repeatable perks. Research, achievements and statistics survive. |
| Achievements | always | 23 milestones, each with a small permanent bonus. |
Everything is data-driven: tabs.json (unlocks), investments.json, research.json, legacy.json, achievements.json and the gamble, research, legacy, contracts and events blocks of rules.json. All bonuses share one vocabulary of effects (engine/effects.js). Texts for research, perks and achievements are in the core locale files; only the theme vocabulary (the gamble's name, the chip/research/legacy currencies, the nine societies) is per theme.
Add a theme
- Copy
public/themes/paperclip/topublic/themes/<your-id>/(lowercase letters, digits, dashes). - Edit
theme.css(palette, font, radius),theme.json(order), and the texts inlocales/*.json. - Reload. The server discovers the folder; no code change and no rebuild list. (With Docker, rebuild the image or mount the folder.)
npm test fails if a theme misses a name for any resource, generator or upgrade, or lacks a language the game supports.
Add a language
- Copy
public/locales/en.jsontopublic/locales/<code>.jsonand translate it (setmeta.nameto the language's own name). - Add
public/themes/<id>/locales/<code>.jsonto every theme.
Missing keys fall back to English, then to the raw key. Strings accept {param} and {@other.key} (embeds another entry, which is how core texts use the theme's vocabulary, e.g. {@theme.res.material}).
Images
Every icon is currently a grey square. To use real images, put files in the theme folder and list them in its theme.json:
{ "order": 1, "assets": { "gen.gen1": "img/autoclipper.svg", "res.units": "img/clip.svg", "upg.click_1": "img/bender.svg" } }
Keys: res.units|funds|material, gen.<id>, upg.<id>. Anything not listed keeps the placeholder.
Saves
- One shared game for all themes, stored in cookies (
ic_game_*, chunked and base64-encoded because a cookie holds ~4 KB), plus one preferences cookie (theme + language). Saves from the first version (one per theme) are merged automatically: the most advanced one is kept. - Save & settings exports the save as
.jsonor.txt(download or copy/paste) and imports either (file picker or pasted text). The file does not depend on the theme. Imports are validated and sanitised: unknown ids are dropped, numbers clamped. - Progress continues while the game is closed: up to 8 h, at 50 % efficiency (
public/data/rules.json). - Cookies are sent with every request to the server. A late-game save is about 4 KB (base64), far below header limits, but it is the reason to keep saves compact.
Tuning the game
Everything numeric is in public/data/: rules.json (market, raw material, marketing, offline, autosave), generators.json, upgrades.json.
- Selling: demand is a smooth curve,
baseDemand × demandMultiplier × (referencePrice / price) ^ elasticityunits/s: lower the price and more people buy, with no ceiling. The best price is where demand just matches your output (selling for less gains no volume, selling for more leaves stock unsold). That point moves with every generator, upgrade and marketing level, and the game does not display it: the market hint only says whether you are selling too cheap, too dear, or about right. - Raw material (wire, herbs…): the price per unit starts high (
startUnitPrice, about a third of the sale price) and falls towardsfloorUnitPriceas total production grows (economies of scale). A lot covers about 10 s of current output (in doublings), multiplied by the "stack" upgrades (batch_size_mult, a chain of five, ×180 in total). A lot costs in proportion to its size, so bigger stacks cost more per purchase while the price per unit still falls with scale. The market is erratic: the price is re-drawn every 10 s (updateEverySeconds) with wide random swings plus frequent shortages and gluts (spikeChance,spikeSize), and is shown to the cent, with ▲/▼ for its last move. The auto-buy upgrade is patient: it waits for a fair price unless stock is nearly gone.