Transcribing Audio with Your Own Key — Guide

Try it first — the first three minutes are on us

You don't need a key to find out whether transcription is any good on your recordings. Pick an audio file, and Comment Coach will transcribe its opening three minutes free, once per account. You'll get the real transcript, from the same model, so what you hear back is what you'd get for the whole file.

If that's useful, the rest of this page is how to make it work on recordings of any length.

Why this one feature needs your own key

Everything else Claude does in Comment Coach — coaching, ideas, translation, research — runs on our key and comes out of your monthly AI allowance. Audio transcription is different, and it's worth being straight about why.

Transcription is billed by the minute of audio, not by the request. A one-minute voice memo and a ninety-minute meeting are the same single action to you and roughly ninety times the cost to run. There's no honest allowance number that covers both, so instead of guessing one, we let you pay OpenAI directly at their rate — which is low — and we take nothing.

What it actually costs

You pay OpenAI, not us. At the time of writing:

Standard — $0.006 a minute. Best accuracy. A 45-minute talk is about 27¢.
Budget — $0.003 a minute. Half the price, slightly rougher on unusual names and accents.

For most people preparing comments, that's a few cents a week. OpenAI requires a minimum credit purchase to start — usually $5 — and at these rates that lasts a very long time. Set a spending limit anyway; step 4 below.

Turning your transcript into organised sections afterwards uses Claude, which is on us and on your normal allowance. Only the audio-to-text step needs your key.

Create an OpenAI account

Go to platform.openai.com and sign up. This is the developer platform, which is a different thing from a ChatGPT subscription — a ChatGPT Plus account does not include API access, and API credit does not give you ChatGPT Plus. If you already pay for ChatGPT, you still need to do this part.

Add a little credit

Under Settings → Billing, add a payment method and buy the minimum credit. Keys don't work without it — a brand new key on a zero balance returns an error, and it's the most common reason people think they've copied the key wrong.

Create the key

Go to API keys and choose Create new secret key. Name it something you'll recognise later, like "Comment Coach".

Copy it now. OpenAI shows a secret key exactly once. If you close the dialog without copying it, you can't retrieve it — delete it and make another. It starts with sk-.

Set a spending limit

Still on the OpenAI site, under Settings → Limits, set a monthly budget — $5 is plenty for ordinary use. This is your ceiling, and it's worth setting before you use the key anywhere, not after. A key with a limit can't surprise you.

Add it to Comment Coach

Open Settings → AI here, find OpenAI, paste the key, and save. Transcription unlocks straight away, with no length limit beyond the 25MB file size.

Where your key is kept

In your browser, on this device, and nowhere else. It is not stored in our database and not synced between your devices — if you use Comment Coach on a phone and a laptop, you'll add it in both places. When you transcribe, the key is sent with that one request so it can reach OpenAI, and it is not written down on our side afterwards.

That also means we can't see your usage or your bill. Check both on the OpenAI dashboard.

If something goes wrong

"Invalid API key" — usually a partial copy. The key is long; make sure you have all of it, starting at sk-, with no trailing space.
"Quota exceeded" or a billing error — the account has no credit, or has hit the limit you set in step 4. Both are on the OpenAI billing page.
It worked and now it doesn't — if you deleted and recreated the key on OpenAI's side, the old one stops working immediately. Paste the new one in Settings.
The file is rejected — 25MB is the ceiling. A long recording exported as MP3 rather than WAV is usually well under it.

Removing it

Clear the field in Settings → AI and it's gone from this device. To be thorough, also delete the key on the OpenAI site — that's the only place it can be revoked for good, and it's the right move if you ever think it has been exposed.