YandexGPT Integration for Mobile Apps: AI Assistant Turnkey

Integrating an AI assistant based on YandexGPT into a mobile app for the Russian market costs from $2,000 and achieves up to 30% savings compared to in-house development. Our team has over five years of experience and has integrated YandexGPT into more than 15 projects, from fintech to e-commerce. We guarantee compliance with App Store Review Guidelines, secure key handling via a server proxy, and full support at all stages. For a typical e-commerce app with 10,000 monthly active users, the monthly API cost is approximately $80 for Lite. Get a consultation to assess your project.

Integrating an AI Assistant with Voice Control

For voice input/output in a Russian app, Yandex SpeechKit offers the best quality of Russian speech among available services. 90% of our clients choose Lite over Pro for their mobile assistants. SDKs for iOS and Android are available via CocoaPods and Maven respectively. STT via WebSocket: wss://stt.api.cloud.yandex.net/speech/v3/stt:streamingRecognize — streaming recognition with partial results. TTS via REST with voice selection (alena, filipp, jane — SSML is supported). For a voice assistant, we recommend combining SpeechKit with YandexGPT: recognition → response generation → synthesis.

A Server Proxy Is Critical for YandexGPT

The IAM token lives for 12 hours and must not be stored in the app. Direct use of the IAM token violates Section 5.1 of the App Store Review Guidelines (Privacy). A server proxy also allows caching responses and managing limits. We use a server proxy: the app sends requests to your backend, which signs them with a service account. This prevents key leakage and gives you control over load.

Yandex Foundation Models API

YandexGPT is available via the Yandex Cloud Foundation Models API. Base URL: https://llm.api.cloud.yandex.net/foundationModels/v1/completion. Authentication uses an IAM token (for user apps) or a service account API key (for server proxy). The IAM token lives for 12 hours and requires refreshing — it is not used directly on the mobile client.

Request structure:

struct YandexGPTRequest: Encodable { let modelUri: String // "gpt://{folder_id}/yandexgpt/latest" let completionOptions: CompletionOptions let messages: [YandexMessage] } struct CompletionOptions: Encodable { let stream: Bool let temperature: Double // 0..1 let maxTokens: String // string, not number — API quirk } 

Important quirk: maxTokens is passed as a string, not a number. This violates the principle of least astonishment and periodically breaks automatically generated clients. modelUri is built as gpt://{folder_id}/{model_name}/{version}. folder_id is the Yandex Cloud folder identifier, it must be stored on the server, not in the app.

How YandexGPT Streaming Works in a Mobile App

To display responses in real time, streaming mode is needed (stream: true in the sync request). In this mode, the server returns chunked responses with partial results. Each chunk is a full JSON with accumulated text (not a delta, but the full text at each step). This is important: when rendering, you must replace the previous text with the new one, not append the delta as in OpenAI.

// Each chunk contains FULL text, not a delta // Correct rendering: func handleChunk(_ response: YandexCompletionResponse) { let fullText = response.result.alternatives.first?.message.text ?? "" DispatchQueue.main.async { self.currentMessage = fullText // replace, not append } } 

YandexGPT supports synchronous mode (/completion) with a 60-second timeout and asynchronous mode (/completionAsync), where you first get an operation_id then poll for the result. Streaming is only available in synchronous mode.

Choosing Between YandexGPT Lite and Pro