> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mentraglass.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Storage

> Persistent key-value storage scoped to your miniapp.

`session.storage` is a phone-local key-value store. It's scoped to the user and
your miniapp, so your keys never collide with another miniapp's, and the data
survives restarts. Keys and values are both strings.

```typescript theme={null}
await session.storage.set("lastNote", "buy milk");
const note = await session.storage.get("lastNote"); // "buy milk"
```

Storage needs no permission and no hardware. Every method is async and
round-trips to the phone.

## Reading and writing

```typescript theme={null}
await session.storage.set("count", "3");
const count = await session.storage.get("count");  // "3", or null if unset
await session.storage.delete("count");
const exists = await session.storage.has("count"); // false
```

| Method            | Returns                   | Notes                              |
| ----------------- | ------------------------- | ---------------------------------- |
| `get(key)`        | `Promise<string \| null>` | `null` when the key isn't set.     |
| `set(key, value)` | `Promise<void>`           | Overwrites silently.               |
| `delete(key)`     | `Promise<void>`           | No-op if the key isn't set.        |
| `has(key)`        | `Promise<boolean>`        | Whether the key is set.            |
| `keys()`          | `Promise<string[]>`       | Every key in your namespace.       |
| `clear()`         | `Promise<void>`           | Drops every key in your namespace. |

## Bulk operations

For hydrating state on startup or saving several keys at once:

```typescript theme={null}
const all = await session.storage.getAll();          // { count: "3", lastNote: "…" }
await session.storage.setMultiple({ a: "1", b: "2" }); // one round-trip
```

| Method                | Returns                           | Notes                                |
| --------------------- | --------------------------------- | ------------------------------------ |
| `getAll()`            | `Promise<Record<string, string>>` | Every key/value pair.                |
| `setMultiple(values)` | `Promise<void>`                   | Writes many pairs in one round-trip. |

<Note>
  Keep the total stored payload small (think under \~1 MB). `getAll()` pulls
  everything across the bridge at once, and a large namespace will stall the
  background context while it resolves. For images, audio, or files, use
  [`session.blob`](/app-devs/core-concepts/blob) instead.
</Note>

## Storing objects

Values are strings, so serialize structured data yourself:

```typescript theme={null}
await session.storage.set("notes", JSON.stringify(notes));
const notes = JSON.parse((await session.storage.get("notes")) ?? "[]");
```