Installation

Add to Cargo.toml

[dependencies]
layer-client = "0.4.5"
tokio        = { version = "1", features = ["full"] }

layer-client re-exports everything you need for both user clients and bots.

Getting API credentials

Every Telegram API call requires an api_id (integer) and api_hash (hex string) from your registered app.

Step-by-step:

1. Go to https://my.telegram.org and log in with your phone number
2. Click API development tools
3. Fill in any app name, short name, platform (Desktop), and URL (can be blank)
4. Click Create application
5. Copy App api_id and App api_hash

SECURITY: Never hardcode credentials in source code. Use environment variables or a secrets file that is in .gitignore.

#![allow(unused)]
fn main() {
// Good — from environment
let api_id:   i32    = std::env::var("TG_API_ID")?.parse()?;
let api_hash: String = std::env::var("TG_API_HASH")?;

// Bad — hardcoded in source
let api_id   = 12345;
let api_hash = "deadbeef..."; // ← never do this in a public repo
}

Bot token (bots only)

For bots, additionally get a bot token from @BotFather:

1. Open Telegram → search @BotFather → /start
2. Send /newbot
3. Choose a display name (e.g. “My Awesome Bot”)
4. Choose a username ending in bot (e.g. my_awesome_bot)
5. Copy the token: 1234567890:ABCdefGHIjklMNOpqrSTUvwxYZ

Optional features

SQLite session storage

layer-client = { version = "0.4.5", features = ["sqlite-session"] }

Stores session data in a SQLite database instead of a binary file. More robust for long-running servers.

LibSQL / Turso session storage — New in v0.4.5

layer-client = { version = "0.4.5", features = ["libsql-session"] }

Backed by libsql — supports local embedded databases and remote Turso cloud databases. Ideal for serverless or distributed deployments.

#![allow(unused)]
fn main() {
use layer_client::session_backend::LibSqlBackend;

// Local
let backend = LibSqlBackend::open_local("session.libsql").await?;

// Remote (Turso cloud)
let backend = LibSqlBackend::open_remote(
    "libsql://your-db.turso.io",
    "your-turso-auth-token",
).await?;
}

String session (portable, no extra deps) — New in v0.4.5

No feature flag needed. Encode a session as a base64 string and restore it anywhere:

#![allow(unused)]
fn main() {
// Export
let s = client.export_session_string().await?;

// Restore
let (client, _shutdown) = Client::with_string_session(
    &s, api_id, api_hash,
).await?;
}

See Session Backends for the full guide.

HTML entity parsing

# Built-in hand-rolled HTML parser (no extra deps)
layer-client = { version = "0.4.5", features = ["html"] }

# OR: spec-compliant html5ever tokenizer (overrides built-in)
layer-client = { version = "0.4.5", features = ["html5ever"] }

Raw type system features (layer-tl-types)

If you use layer-tl-types directly for raw API access:

layer-tl-types = { version = "0.4.5", features = [
    "tl-api",          # Telegram API types (required)
    "tl-mtproto",      # Low-level MTProto types
    "impl-debug",      # Debug trait on all types (default ON)
    "impl-from-type",  # From<types::T> for enums::E (default ON)
    "impl-from-enum",  # TryFrom<enums::E> for types::T (default ON)
    "name-for-id",     # name_for_id(u32) -> Option<&'static str>
    "impl-serde",      # serde::Serialize / Deserialize
] }

Verifying installation

use layer_tl_types::LAYER;

fn main() {
    println!("Using Telegram API Layer {}", LAYER);
    // → Using Telegram API Layer 224
}

Platform notes