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All tests run on an 8-year-old MacBook Air.
Waiting 5 seconds for an AI response with no feedback feels broken. Streaming fixes this — tokens appear as they’re generated, just like ChatGPT.
Here’s how to wire Gemini streaming into a Tauri app so the response appears word by word in your UI.
The API endpoint
Replace :generateContent with :streamGenerateContent:
POST /v1beta/models/gemini-2.5-flash-preview:streamGenerateContent?key=API_KEY
The response is a stream of JSON objects, one per token batch.
Rust: reading the stream
use reqwest::Client;
use futures_util::StreamExt;
use tauri::Emitter;
#[tauri::command]
pub async fn stream_gemini(
prompt: String,
api_key: String,
window: tauri::Window,
) -> Result<(), String> {
let client = Client::new();
let url = format!(
"https://generativelanguage.googleapis.com/v1beta/models/
gemini-2.5-flash-preview:streamGenerateContent?key={}",
api_key
);
let body = serde_json::json!({
"contents": [{"parts": [{"text": prompt}]}]
});
let mut stream = client
.post(&url)
.json(&body)
.send()
.await
.map_err(|e| e.to_string())?
.bytes_stream();
while let Some(chunk) = stream.next().await {
let bytes = chunk.map_err(|e| e.to_string())?;
let text = String::from_utf8_lossy(&bytes);
// Each chunk is a JSON object — extract the text
if let Ok(json) = serde_json::from_str::(&text) {
if let Some(token) = json["candidates"][0]["content"]["parts"][0]["text"].as_str() {
// Emit each token to the frontend
window.emit("ai-token", token).ok();
}
}
}
window.emit("ai-done", ()).ok();
Ok(())
}
React: receiving tokens
import { listen } from '@tauri-apps/api/event';
import { invoke } from '@tauri-apps/api/core';
import { useState, useEffect, useRef } from 'react';
export function StreamingDiagnosis() {
const [response, setResponse] = useState('');
const [isStreaming, setIsStreaming] = useState(false);
const unlistenRef = useRef<(() => void) | null>(null);
const startStream = async (prompt: string) => {
setResponse('');
setIsStreaming(true);
// Listen for tokens
unlistenRef.current = await listen('ai-token', (event) => {
setResponse(prev => prev + event.payload);
});
// Listen for completion
const unlistenDone = await listen('ai-done', () => {
setIsStreaming(false);
unlistenDone();
});
await invoke('stream_gemini', { prompt, apiKey: 'YOUR_KEY' });
};
// Cleanup on unmount
useEffect(() => {
return () => { unlistenRef.current?.(); };
}, []);
return (
{response}{isStreaming && ▊}
startStream('Analyze this error...')}>
Diagnose
);
}
The blinking cursor
A small CSS detail that makes streaming feel polished:
.cursor {
animation: blink 1s step-end infinite;
}
@keyframes blink {
0%, 100% { opacity: 1; }
50% { opacity: 0; }
}
Appears while streaming, disappears when ai-done fires.
Result
5-second wait with no feedback → tokens appearing immediately, word by word. Same content, completely different feel.
Hiyoko PDF Vault → https://hiyokoko.gumroad.com/l/HiyokoPDFVault
X → @hiyoyok
