Struct ClientBuilder 

pub struct ClientBuilder<K = NoApiKey, P = NoProvider> { /* private fields */ }

Type-state builder for DefaultClient.

The two type parameters K and P track whether the required fields have been supplied:

• K is NoApiKey until api_key is called, then WithApiKey.
• P is NoProvider until provider is called, then WithProvider.

build is only available when both are WithApiKey and WithProvider. Attempting to call it in any other state is a compile error.

All optional knobs (base_url, timeout, transport, …) are available at any point in the chain and do not affect the type-state.

Examples

use liter_llm::ClientBuilder;

let client = ClientBuilder::new()
    .api_key("sk-…")
    .provider("openai")
    .timeout(std::time::Duration::from_secs(30))
    .build()?;

Implementations

impl ClientBuilder<NoApiKey, NoProvider>

pub fn new() -> Self

Create a new builder with no key and no provider set.

Call api_key and provider to advance the type state, then call [build] when both are set.

impl<K, P> ClientBuilder<K, P>

pub fn api_key(self, key: impl Into<String>) -> ClientBuilder<WithApiKey, P>

Set the API key for authentication.

Accepts any value that converts into a SecretString (including &str and String). The secret is zeroed on drop.

Calling this method transitions the K type parameter from NoApiKey to WithApiKey.

pub fn provider( self, provider_name: impl Into<String>, ) -> ClientBuilder<K, WithProvider>

Set the provider by name or model-hint string.

The string is forwarded to provider auto-detection in the same way that the model_hint argument to DefaultClient::new works. Use a slash-prefixed name (e.g. "openai", "groq/llama3-70b", "anthropic") or a bare model name.

Calling this method transitions the P type parameter from NoProvider to WithProvider.

pub fn base_url(self, url: impl Into<String>) -> Self

Override the provider base URL for all requests.

Trailing slashes are trimmed automatically. When set, provider auto-detection is bypassed and all requests go to this URL.

pub fn timeout(self, timeout: Duration) -> Self

Set the per-request timeout (default: 60 s).

pub fn max_retries(self, retries: u32) -> Self

Set the maximum number of retries on 429 / 5xx responses (default: 3).

pub fn max_response_bytes(self, limit: usize) -> Result<Self>

Limit retained HTTP bodies; successful streams keep their existing frame bounds.

Errors

Returns an error when the limit is zero.

pub fn transport(self, config: TransportConfig) -> Self

Set HTTP connection pooling, TCP keepalive, DNS caching, and version selection.

pub fn load_env(self, enabled: bool) -> Self

Enable or disable automatic API key loading from environment variables.

When true, the client will attempt to read the provider’s designated environment variable (e.g. OPENAI_API_KEY) if no key was set via api_key. Defaults to false in ClientBuilder (unlike ClientConfigBuilder which defaults to true) because the type-state design signals that the key should be provided explicitly.

pub fn credential_provider(self, provider: Arc<dyn CredentialProvider>) -> Self

Set a dynamic credential provider for token-based or refreshable auth.

When configured, the client calls resolve() before each request instead of using the static API key for authentication.

impl ClientBuilder<WithApiKey, WithProvider>

pub fn build(self) -> Result<DefaultClient>

Consume the builder and construct a DefaultClient.

This method is only available when both api_key and provider have been called. The compiler enforces this at the type level.

Errors

Returns LiterLlmError::Authentication if the provider requires an environment variable that is unset (only relevant when the API key supplied via [api_key] is an empty string and load_env is true).

Returns LiterLlmError::Http if the underlying HTTP client cannot be constructed.

Trait Implementations

impl Default for ClientBuilder<NoApiKey, NoProvider>

fn default() -> Self

Returns the “default value” for a type.