Java SDK

Send one chat.completions request from Java with openai-java, then reuse the same client shape in your application code.

Minimum working example

Add the SDK:

implementation("com.openai:openai-java:4.29.0")

Then run one chat.completions request:

import com.openai.client.OpenAIClient;
import com.openai.client.okhttp.OpenAIOkHttpClient;
import com.openai.models.chat.completions.ChatCompletion;
import com.openai.models.chat.completions.ChatCompletionCreateParams;

public class BasicUsage {
    public static void main(String[] args) {
        String apiKey = System.getenv("GONKAGATE_API_KEY");
        if (apiKey == null || apiKey.isBlank()) {
            throw new IllegalStateException("missing GONKAGATE_API_KEY");
        }

        OpenAIClient client = OpenAIOkHttpClient.builder()
            .apiKey(apiKey)
            .baseUrl("https://api.gonkagate.com/v1")
            .build();

        ChatCompletionCreateParams params = ChatCompletionCreateParams.builder()
            .addUserMessage("Say hello from GonkaGate in one sentence.")
            .model("qwen/qwen3-235b-a22b-instruct-2507-fp8")
            .build();

        ChatCompletion completion = client.chat().completions().create(params);

        completion.choices().forEach(choice ->
            choice.message().content().ifPresent(System.out::println)
        );
    }
}

Expected result: if this prints text, your Java client is wired correctly.

Use a current model ID from GET /v1/models. The example value above is only illustrative.

What you need before you run it

• Java 8+, because that is the minimum version required by openai-java
• A gp-... API key stored in GONKAGATE_API_KEY
• Enough available balance for the request
• A current GonkaGate model ID
• If you use Maven instead of Gradle, use the same coordinates: com.openai:openai-java:4.29.0

Java-specific notes

• Set .baseUrl("https://api.gonkagate.com/v1") before you build the client.
• Reuse one client per application where possible. The SDK maintains connection pools and thread pools internally.
• The default client is synchronous. If you need CompletableFuture-based execution, switch to client.async() or create an OpenAIOkHttpClientAsync.
• If you copy older snippets, update the dependency version together with the rest of the example.

Common errors and limits

• If you forget .baseUrl("https://api.gonkagate.com/v1"), the client still points at the default OpenAI endpoint.
• 401 invalid_api_key usually means the key is missing, malformed, revoked, or tied to an unavailable account state.
• 404 model_not_found means the model ID is no longer available. Refresh it from GET /v1/models.
• 429 insufficient_quota means the available prepaid USD balance is too low for the request.

See also

• OpenAI SDK compatibility for the shared base URL, key format, model-selection rules, and additive usage fields across runtimes.
• Authentication and API Keys for key creation, secure storage, and rotation.
• GonkaGate API Reference Overview when the first Java request works and you need exact request fields, streaming behavior, and failure policy.
• GET /v1/models for the current machine-readable model IDs.
• OpenAI to GonkaGate Migration Guide if you are switching already-working OpenAI code instead of starting from zero.