I just want to thank Godnoken for this amazing app that works perfectly with the new visual novel The Quintessential Quintuplets. I’m so happy I found something that works this well ! At the same time, I want to share my experience using the ChatGPT API for AI-powered translation from Japanese to English (I personally use French for myself), so maybe it will help people who wants to do the same. At first, even with the AI I was making mistakes, but here are the options I found to work best.

Here’s the key info: you need to spend at least $5 to access the API (which is enough for a full run of a game, imo). I use GPT-5 mini. It’s more expensive than GPT-5 nano, but I find the nano doesn’t translate as well. I also limit tokens and reasoning effort so I don’t pay for unnecessary processing (you should really do so). Here’s what I put in the app:

Endpoint URL: https://api.openai.com/v1/chat/completions

Headers (JSON): 

{
    "Content-Type": "application/json",
    "Authorization": "Bearer [YOUR KEY HERE]"
}

Body (JSON): adjust the context for your game, but don’t include too many details or it will cost more. You can also change the model if you want so:

{
    "model": "gpt-5-mini",
    "reasoning_effort": "minimal",
    "max_completion_tokens": 150,
    "messages": [
        {
            "role": "system",
            "content": "Translate from Japanese to clear, natural English, like a real conversation. Context: The Quintessential Quintuplets in a magical universe. Correct any OCR mistakes, and only provide the final English dialogue."
        },
        {
            "role": "user",
            "content": "%text%"
        }
    ]
}

Text Output Path: choices[0].message.content

So with this phrase for example : うう…また呪文が失敗した…どうしていつも君がいるときに薬が爆発するの、五月？ I got in 2 or 3 seconds : Ugh… the spell failed again. Why does the potion always explode whenever you're around, Itsuki?

It’s great because in the game settings I make the text appear immediately, so by the time the character finishes speaking in Japanese, I already have the translation! I also recommend you to use the automatic mode and pause it, then use the OneShot button each time. For me, it’s a Switch game, so I capture it with a capture card and put the translation on OBS (and the game itself is on my second screen).

After a solid hour of gameplay, I’ve only spent €0.04 out of the €5 in my account.

Anyway, that’s it for my feedback on using the GPT API. Thanks again, Godnoken! Hope it will help people who are not too familiar with the API :)

Hey bentleys!

Thank you so much for the great feedback and guide! I'm very glad and proud that you're enjoying using my application.

I should have made at least a basic guide for the Custom API and Llama weeks ago, I'm sorry I haven't gotten to it.. I will pin this thread for now.

Cheers! 💙