Resimbinator

A web-app simulator for Path of Exile 1's Unpredictable Recombination. Paste two items from the game (or hit "Random pair"), mark the mods you want, and see the chance — broken down by which base wins, with the math behind it.

Live: https://resimbinator.vercel.app

What it does

• Paste from PoE (Ctrl+C in-game). Parses the clipboard format with or without "Show Modifier Type Hints"
• Or generate a random pair if you don't want to grab items by hand — picks two bases of the same item class, samples real mods (~70% regular / 25% NNN / 5% exclusive) so the chip variety is visible
• Tick desired mods → chance % updates instantly, plus a per-base split (base ← item 1 / base ← item 2) that exposes the NNN ladder mechanic
• Show breakdown dialog — walks through the math: the 50/50 base pick, the combined mod pool with per-base eligibility (✓/✗ with reasons like "requires evasion on the base"), the Table 1 row for affix counts, and the weighted-sum formula
• Inline editing — × any mod to delete, "+ Add prefix/suffix" to search the mod-DB and insert one (filtered by what's eligible for the host base)
• Recombine once → modal with the rolled item; Run 1000× → histogram of prefix/suffix counts + hit rate + expected attempts
• Cost calculator → enter a divine-per-try cost, total expected cost shows up next to the chance
• Library dialog with five tabs:
  • Examples — preset scenarios that demonstrate each rule (NNN_Defence, NNN_Influenced, exclusive collision, fractured-host)
  • My saved — name and store scenarios in localStorage
  • Compare — pick saved scenarios, see chance / per-base split / expected tries / cost in a table
  • Plan — chain saved scenarios as sequential steps with cumulative cost
  • Workflow — wire stages into a DAG (multi-step crafts like the NNN-ladder method); cost rolls up the tree
• Help dialog with the full mod-category reference (NNN, Fractured, Exclusive, edge cases not modelled)
• Auto-save to localStorage; share a scenario via URL

Tech

• SvelteKit 2 (Svelte 5 runes) + TypeScript + Tailwind, static-adapter SPA
• Pure-TS recombinator engine — no Svelte deps, fully unit-tested
• RePoE-derived mod database (~12k entries) built via bun run update-mod-db
• Bun for install / build / test
• Vercel for hosting (vercel.json included)

Run locally

bun install
bun run dev

Open http://localhost:5173, paste an item or hit "Generate random pair".

bun run build && bun run preview   # production build + local preview
bun run test                       # vitest suite
bun run check                      # svelte-check + tsc

Mod database

The UI ships with a tiny dev fixture (static/mod-db-fixture.json) that's enough for the categorizer's rule tests. To populate the full RePoE-derived database (~3 MB, one-time, requires network):

bun run update-mod-db

This writes static/mod-db.json. The UI prefers mod-db.json and falls back to the fixture.

Project layout

src/lib/recombinator/    pure-TS math engine (Table 1 sampler, eligibility, exact + Monte Carlo, explain)
src/lib/poe-clipboard/   clipboard parser
src/lib/mods/            mod database, categorizer, translator
src/lib/ui/              UI state, persist, URL share, generate, presets, analyze
src/components/          Svelte components (panels, dialogs, mod rows)
src/routes/              SvelteKit pages
src/cli/                 stdin/stdout CLI (probability/simulate/parse/translate)
scripts/                 build-mod-db.ts
tests/                   unit + integration + snapshot tests
docs/                    design notes, NNN-ladder workflow reference

Validation

bun run test runs the full suite — currently 146 tests across 26 files:

• Engine unit + integration tests, guide §6 (grasping mail breach) and §7 (wand counterweight ≈ 35%) examples, cross-check property test against Monte Carlo
• Parser unit tests + fixture snapshots for ~10 clipboard variations
• Categorizer rule coverage + translator round-trips
• UI: state helpers, localStorage round-trip, URL encode/decode
• CLI integration tests

Caveats / not modelled

• Legacy IIQ mod (permanent leagues only)
• Has Abyssal Socket + base-at-max-sockets interaction
• Workflow tab assumes one successful donor per stage — variance from batched parallel attempts isn't modelled
• Generated stat texts are humanized RePoE stat IDs (additional_strength → "+47 to Strength"), not the exact PoE wording

Disclaimer

Not affiliated with or endorsed by Grinding Gear Games. Path of Exile is © Grinding Gear Games. Mod data sourced from the open-source RePoE project. Recombinator mechanics are based on the community guide and the PoE Wiki.

License

MIT.