If this is useful, a ❤️ helps others find it. Everything I keep looking up when building with Gemini — in one place. Model Context Best for gemini-2.5-flash-preview 1M tokens General use, thinking, fast gemini-2.5-pro-preview 1M tokens Complex reasoning, best quality gemini-1.5-flash 1M tokens Stable, production-ready gemini-1.5-pro 2M tokens Longest context gemini-2.0-flash-lite 1M tokens Lowest latency, highest volume For most use cases: gemini-2.5-flash-preview Model RPM TPM RPD Gemini 2.5 Flash Preview 10 250,000 500 Gemini 1.5 Flash 15 1,000,000 1,500 Gemini 1.5 Pro 2 32,000 50 Gemini 2.0 Flash Lite 30 1,000,000 1,500 RPM = requests per minute, TPM = tokens per minute, RPD = requests per day curl https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-preview:generateContent \ -H "Content-Type: application/json" \ -H "x-goog-api-key: YOUR_API_KEY" \ -d '{ "contents": [{"parts": [{"text": "Your prompt here"}]}] }' { "system_instruction": { "parts": [{"text": "You are a helpful assistant."}] }, "contents": [ {"role": "user", "parts": [{"text": "Your prompt here"}]} ] } curl https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-preview:streamGenerateContent \ -H "Content-Type: application/json" \ -H "x-goog-api-key: YOUR_API_KEY" \ -d '{"contents": [{"parts": [{"text": "Tell me a story"}]}]}' use reqwest::Client; use serde_json::json; pub async fn call_gemini(prompt: &str, api_key: &str) -> Result { let client = Client::new(); let url = format!( "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-preview:generateContent?key={}", api_key ); let body = json!({ "contents": [{"parts": [{"text": prompt}]}] }); let res = client.post(&url).json(&body).send().await?; let data: serde_json::Value = res.json().await?; let text = data["candidates"][0]["content"]["parts"][0]["text"] .as_str() .unwrap_or("") .to_string(); Ok(text) } Code Meaning Fix 400 Bad request / token limit Shorten prompt 403 Invalid API key Check key 429 Rate limit hit Wait and retry 500 Internal error Retry 503 Overloaded Wait 2s, retry once 1 token ≈ 4 characters in English 1 token ≈ 2–3 characters in Japanese 100 lines of logcat ≈ 3,000–5,000 tokens 1 page of PDF text ≈ 500–800 tokens Go to aistudio.google.com Sign in with Google Click "Get API Key" Done — no credit card required Hiyoko PDF Vault → https://hiyokoko.gumroad.com/l/HiyokoPDFVault @hiyoyok