Pokémon HOME is the strictest legality gate in the entire Switch Pokémon ecosystem. If a Pokémon deposits to HOME successfully, it has cleared a tougher check than any individual game runs on its own. This is a practical look at what HOME's validator actually cares about — and why most "is my Pokémon legal?" questions collapse into "does it pass HOME?"

Why HOME is the gate that matters

Each mainline game runs its own legality checks on the data it produces. HOME runs checks on everything coming in, from every game, all at once. That means HOME has to encode the encounter rules, move legality, form data, and hidden-value rules for six different games and enforce them consistently.

The upshot: if a Pokémon passes HOME, it's effectively certified as legal by the strictest common denominator. If it fails HOME, no amount of "it looks right in my game" matters — it can't move, it can't be stored, and it can't be transferred forward.

What HOME actually validates

1. Species / form / origin alignment

HOME knows which species and forms exist in which games. A Kantonian Meowth with a SV origin mark is fine; a Galarian Meowth with a BDSP origin mark is not. Regional forms, gigantamax states, and game-exclusive formes all map to specific origin games.

2. Move legality

Every move has an origin: where and how the Pokémon could legally learn it. HOME walks the move set and asks, "could this Pokémon have learned all of these moves in the games it claims to have come from?" A Charizard with Fire Blast is fine anywhere. A Charizard with a move it could only learn via a specific Move Tutor in a specific game has to have been in that game at some point, and HOME checks.

3. Ability legality

Abilities have slots (1, 2, Hidden), and each encounter type determines which slots are valid. HOME enforces the slot against the encounter. Hidden abilities from encounters that can't roll hidden fail.

4. Encounter marks, balls, and met data

Origin marks (the Game Freak icon shown in Pokémon's summary) have to match where the Pokémon was actually obtained. Balls have to match what the encounter allowed. Met-level can't be below the encounter minimum. Met-location has to be a real location in the origin game.

5. Hidden-value consistency

The Encryption Constant (EC), Personality ID (PID), Trainer ID, Secret ID, and Shiny flag all have mathematical relationships in each game's RNG. HOME verifies these relationships. A shiny whose PID/TID math doesn't work out fails. An EC-PID relationship that a real encounter could never have produced fails.

6. Ribbons and markings

A ribbon has to come from a game that gave that ribbon. Event ribbons have to come from specific events. Markings have to be reachable.

What HOME does not check

Just as important: HOME does not care whether a Pokémon was caught, bred, or generated. It cares whether the data matches what the games would have produced. The word "legal" in this context means "internally consistent with the game's own rules" — not "came from a specific source."

This is why a correctly-built genned Pokémon and a shiny caught through RNG abuse (a well-known legitimate technique) are treated identically by HOME. Same data patterns. Same validator decision.

Common reasons deposits fail

  • Moves from the wrong game. A SwSh move on an SV-origin Pokémon that never visited SwSh.
  • Impossible hidden abilities. Hidden ability on an encounter slot that couldn't roll it.
  • Wrong ball. Master Ball on a gift Pokémon; Apricorn balls on a species outside their origin game.
  • Mismatched Shiny math. Shiny flag set on a Pokémon whose PID/TID doesn't produce a shiny result when calculated through the game's algorithm.
  • Impossible met-level or location. Level-below-minimum, location that doesn't exist, location in a game that never had the species.

How this informs genning

If you're receiving a Pokémon from any service, the only meaningful question is: "will this pass HOME?" Not "does it look right in my game" — HOME will catch what the game's casual inspection doesn't.

At GenPKM, HOME compatibility is non-negotiable. Every Pokémon we trade passes a PKHeX legality check tuned to HOME's own rule set before it leaves our bot. That's the only standard that matters, and it's the one we build against.

For a broader look at the safety question, see Is Pokémon Genning Safe?.