Know your team's type coverage before you take it into battle.
CoverDex is a free Pokémon team builder that shows you, instantly, what your team hits hard, what it's weak to, and where the holes are. Build a team, switch to the Analysis tab, and see the whole picture — no math, no spreadsheets, no guessing.
It's built for two kinds of trainers: competitive players who want to stress-test a team before committing to it, and ROM hack / nuzlocke players who need a tool that can handle custom typings and off-dex Pokémon, which most team builders simply can't.
No account, no ads, nothing sent to a server. CoverDex runs entirely on your device, works offline once it's loaded, and never asks for your data.
Open the web app → Also available as a native Android app — see Get CoverDex below.
- See the whole board at once. Every type your team covers offensively, every shared weakness, every uncovered type — one screen, updated live as you edit your team.
- Ability-aware coverage. Levitate, Flash Fire, Water Absorb and other coverage-relevant abilities are factored into the defensive math automatically, not just shown as a badge.
- Smart suggestions, not guesswork. CoverDex ranks which Pokémon would actually improve your team, weighing the new coverage they add against the weaknesses they'd introduce.
- "Surprise Me" generator. Don't want to start from scratch? Lock in a Pokémon or two, set a few constraints (starters, legendaries, mega evolutions...), and let CoverDex build a coverage-optimized team around them.
- First-class ROM hack support. Override any Pokémon's type on a per-slot basis for a randomizer or a hack with different typings — every calculation adapts to match, without touching the real data.
- Speaks Showdown. Import a team you already built on Pokémon Showdown, or export yours in the same format to share or battle with.
- Actually offline. Pokémon data downloads once, then CoverDex never needs the internet again — install it and take it anywhere.
| Web app | Open marcogn.github.io/CoverDex in any modern browser. Works on desktop and mobile, and can be installed as an app — see Installing as a PWA. |
| Android app | Download the latest APK from the Releases page and install it directly on your device. Not on the Play Store yet — see Android app for what that means in practice. |
Both versions have the same features, restyled to feel native on each platform. They're independent installs and don't share data with each other — a team built on the web app stays on the web app, and a team built on the Android app stays there.
- Multiple saved teams, six slots each, stored on your device.
- Full PokéAPI species search, including alternate forms, with instant results as you type.
- Per-slot type overrides for ROM hack typings, kept separate from the underlying species data.
- Ability picker with known coverage effects (immunities, multipliers) reflected directly in the analysis, plus free-text entry for anything a randomizer throws at you.
- Four move slots per Pokémon, from PokéAPI or entered as custom moves, with move-aware offensive coverage when you use them.
- A personal custom-Pokémon roster for anything that doesn't exist in the official Pokédex — build it once, reuse it across every team.
- Deep coverage analysis: per-Pokémon breakdown, an offensive grid, a defensive grid, shared team weaknesses, and a list of everything your team doesn't hit.
- Ranked suggestions for who to add or swap in, including your custom roster if you want it in the mix.
- "Surprise Me" team generator with seed Pokémon and fine-grained slot budgets for starters, legendaries/mythicals, mega evolutions, Dynamax/Gmax forms, and custom Pokémon.
- English and Italian, with more languages easy to add.
- Showdown-format import/export, via clipboard or
.txtfile. - Installable, offline-first PWA on desktop, iOS, and Android.
CoverDex doesn't require a Pokémon to exist in the official Pokédex to be usable:
- In any slot, choose Custom (or just type a name PokéAPI doesn't know) and set its types and moves by hand.
- Save it to your custom roster to reuse it across every team.
- Enable Include custom roster in the picker to bring saved custom Pokémon into a team, and into the suggestion engine.
- Rename or delete custom Pokémon any time from the Custom Roster panel.
Combined with per-slot type overrides, this covers the two things a "real" Pokédex team builder can't: Fakemon and re-typed movesets from a randomizer or ROM hack.
CoverDex reads and writes Pokémon Showdown-style
team text, so you can move a team in or out in seconds. On export it
also writes a # Types: ... comment per Pokémon, which is how a ROM
hack's type overrides survive the round trip — Showdown itself ignores
the comment, so the file still works normally there too. Unknown moves
on import are kept as flagged placeholders rather than silently dropped,
so you always know what still needs a closer look.
Desktop (Chrome, Edge, Brave) — open the web app, then click the install icon in the address bar (or the menu → Install CoverDex).
iOS (Safari) — open the web app, tap the share icon, then Add to Home Screen.
Android (Chrome) — open the web app, tap the menu, then Install app / Add to Home screen. (This installs the PWA; the native Android app from Get CoverDex above is a separate, independent option.)
On first launch, CoverDex downloads the full Pokémon dataset — this takes roughly 30–90 seconds depending on your connection, with a progress bar showing what's happening. After that, everything is cached on-device and every later launch is instant, fully offline included.
CoverDex also ships as a native Android app, wrapping the same web app in a lightweight native shell so it installs, launches, and feels like a normal Android app. It's currently sideload-only — there's no Play Store listing yet, so you install the APK from the Releases page the same way you would any APK from outside the Play Store (you'll need to allow installs from that source once).
Building it yourself only takes two commands once the prerequisites are in place:
npm run android:build # builds the Android bundle and syncs it into android/
npm run android:open # opens the project in Android StudioSee docs/android/BUILD.md for prerequisites,
signing a release build, and CI details.
npm install
npm run generate-icons # generate PWA icons (gitignored, not committed)
npm run dev # dev server at http://localhost:5173
npm run test# run the test suiteRequires Node.js 18+ (the Android tooling separately requires Node 22+,
see above). Full setup, environment variables, and the GitHub Pages
deployment process are in docs/DEVELOPMENT.md.
To understand how the app is put together before changing anything, read:
docs/ARCHITECTURE.md— how the app fits together: data flow, the two calculation engines, the web/Android split.docs/STATUS.md— current snapshot of what's done and what's still open.CLAUDE.md— rules and invariants for anyone (human or AI) changing the code, with pointers to the more detailed docs it summarizes.
Contributions are welcome — see
.github/CONTRIBUTING.md for the workflow
and house rules.
- No accounts and no cloud sync — a team lives only on the device (and the platform, web or Android) it was created on.
- The Pokémon dataset only refreshes when you ask it to, from Settings → Data → Redownload.
- Suggestions look at the top candidates by coverage gain, not an exhaustive search across every possible substitution.
- The Android app is sideload-only for now; there's no Play Store listing.
CoverDex is an independent fan project, built by marcogn in close collaboration with Claude, Anthropic's AI coding assistant — Claude wrote and reviewed most of the code, under direct human design and review at every step. Pokémon data comes from PokéAPI; team import/export follows the Pokémon Showdown format. Pokémon and all related media are trademarks of Nintendo, Game Freak, and The Pokémon Company — CoverDex is unofficial, non-commercial, fan-made software with no affiliation to any of them.