AI model performance vs price comparison tool. Scatter plot of Humanity's Last Exam scores against price per million tokens, with interactive filters.

Built with Fresh v2 — Deno's full-stack web framework.

Stack #

Layer	What
Runtime	Deno 2.9+
Framework	Fresh v2 (file-based routing, islands)
UI	Preact + `@preact/signals`
Chart	Chart.js v4 (canvas scatter)
CSS	Tailwind v4
Desktop	`deno desktop` (built-in, no install)
Test	Deno built-in test runner + `@std/expect`

Quick start #

deno task dev              # Vite dev server with HMR

Open http://localhost:5173 — redirects to /compare.

Commands #

Command	What
`deno task dev`	Vite dev server with HMR
`deno task build`	Production build to `_fresh/`
`deno task start`	Serve production build
`deno task check`	Format + lint + type-check
`deno task test`	Run all tests
`deno task desktop`	Build desktop binary (run `build` first)
`deno task desktop-dev`	Desktop app with HMR
`deno fmt`	Auto-format
`deno lint`	Lint
`just github-push`	Push to GitHub (triggers CF Worker deploy)

Data format #

Supply your own JSON array via Paste JSON button or drag-and-drop a .json file:

[
  {
    "name": "GPT-5.6 Sol",
    "provider": "OpenAI (US)",
    "performance": 43.1,
    "price_per_million_tokens_in_out": [5.00, 30.00],
    "category": "Frontier Flagship / Reasoning",
    "released": "2026-07-09"
  }
]

Field	Type	Description
`name`	string	Model name (shown on plot)
`provider`	string	Company name (colors the dot)
`performance`	number	Humanity's Last Exam score (%)
`price_per_million_tokens_in_out`	[number, number]	`[input_price, output_price]`
`category`	string	Model category / tier
`released`	string	Release date `YYYY-MM-DD`

A demo dataset is pre-loaded with 6 models.

Controls #

Models per provider — limits how many recent models each provider shows
Price (Input / Output) — toggles Y axis between input and output token pricing
Scale (Log / Linear) — toggles Y axis scale
Data (Paste JSON) — paste your own dataset

Desktop app #

Fresh 2.x is auto-detected by deno desktop (built into Deno 2.9+):

deno task build
deno task desktop          # production desktop binary
deno task desktop-dev      # dev mode with HMR

The binary bundles your code, the Deno runtime, and a webview renderer into a single executable. Output is in chartGPT/.

Cloudflare Workers #

Push to GitHub — Cloudflare picks it up, builds, and deploys:

just github-push

What Cloudflare runs on its end:

Build: npx deno install --allow-scripts=npm:sharp,npm:workerd && npx deno task build

Deploy: npx wrangler deploy

Key files:

server.js — Worker entry, imports _fresh/server/server-entry.mjs, exports { fetch: server.fetch }
wrangler.jsonc — Config with main: "./server.js", assets at _fresh/client

Gotchas:

Deno.readTextFile breaks in Workers — use import ... with { type: "json" } instead
@cloudflare/vite-plugin conflicts with Fresh SSR build order — wrangler direct is the working path

Tests #

deno task test

Tests cover: data integrity, price extraction, filtering logic (N-most-recent per provider), and entry validation — all pure functions in utils/compare.ts.

Architecture #

routes/
  compare.tsx      — chart page (loads demo data, renders island)
  index.tsx         — redirects to /compare
islands/
  CompareChart.tsx  — interactive chart island (Chart.js canvas)
components/
  Button.tsx        — shared UI primitives
utils/
  compare.ts        — shared types & pure functions
tests/
  compare_test.ts   — tests
assets/
  styles.css        — Tailwind v4 + Geist font import
static/
  demo-models.json  — default dataset

Clone this repository

ChartGPT #