Bring your own AI key

1. Open aistudio.google.com/apikey and sign in.
2. Accept the terms if you’re asked. A Google Cloud project and a first API key are created for you, so there’s nothing to configure on that side.
3. Select Create API key (the section is called Get API key), then copy the key.
4. In FairThen, go to Settings → Advanced, tap Google AI Studio, paste the key, then Test connection and Save.

Worth knowing

• Make a fresh key rather than reusing an old one. Google has been retiring its older Standard keys through 2026, unrestricted ones first, and issues a different kind now. FairThen doesn’t care what a key looks like, but an old one may already be refused by Google.
• The free tier is the one that learns from you. Google may use what you send on it to improve its products, and reviewers can see it. It doesn’t apply if you’re in the UK, the EEA or Switzerland, and moving to a paid tier stops it. Their API terms spell out both.
• It has to be a key you can copy out of AI Studio. A service-account JSON file or a gcloud credential isn’t something you can paste into the key field.

Official pages

• Get a key
• Google’s own walkthrough
• Your rate limits
• How Google uses your data

1. Sign in at dash.cloudflare.com. The free Workers plan is enough and no card is needed.
2. Open Workers AI, then select Use REST API.
3. Select Create a Workers AI API Token, then Create API Token, then Copy API Token. It’s shown once.
4. On the same screen, copy your Account ID. It’s 32 hex characters, so 0 to 9 and a to f.
5. In FairThen, go to Settings → Advanced, tap Cloudflare Workers AI, paste the token and the Account ID, then Test connection and Save.

Worth knowing

• Tapping Get a key in the app opens Cloudflare’s general API Tokens page rather than the Workers AI screen above, so those three buttons won’t be there. That page works too: Create Token, give the token both Workers AI · Read and Workers AI · Edit, and pick the Account ID up separately.
• To find the Account ID on its own, press Ctrl+K in the dashboard (Cmd+K on a Mac) and search for “Copy account ID”, or look under Workers & Pages → Account Details.
• The Account ID is not the Zone ID sitting next to it on a domain’s page, and it isn’t the token’s own id either. Those are the two things people paste by mistake.

Official pages

• Token and Account ID walkthrough
• Finding your Account ID
• Free allocation and pricing
• What Cloudflare does with your data

What you fill in

• Endpoint URL. The base, usually ending in /v1/. FairThen adds chat/completions itself, and adds the trailing slash if you forget.
• Default model. The exact model id your endpoint expects. It’s the fallback: a tool that has its own model picked uses that one instead.
• API key. Whatever that endpoint authenticates with.

What FairThen sends

One POST to {your endpoint}chat/completions with your key as a bearer token, carrying a system message with the instructions and a user message with the text plus, where the feature needs one, an image as an inline base64 data: URI. It asks for a JSON schema first, and if the endpoint answers 400 to say it doesn’t understand that, it retries in plain JSON mode.

What the endpoint has to do

• https, no exceptions. An http:// endpoint is refused outright, because your key would cross the network in the clear.
• No query string, no fragment, and no username or password in the URL. Any of the three is rejected before a request goes out.
• Answer on that exact URL. Redirects aren’t followed, on purpose, so your key can’t be bounced somewhere you didn’t agree to. An endpoint that 301s or 302s elsewhere will never work.
• For Receipt scan, accept an image inline as base64. Some endpoints only take a public image URL, and those won’t work here.
• Answer inside the budget. Receipt scan allows roughly a minute per attempt and three tries, and stops at about two and a half minutes overall. Very slow local hardware may not make it.

We can’t test or support an endpoint we’ve never seen, so this option really is at your own risk. Test connection sends a tiny text prompt, which proves the key and the URL work. Whether a model can actually read an image is checked separately, when you pick a model for Receipt scan.

Two lists, in this order: Providers is where a key lives, and AI tools is where Receipt scan picks which provider and model to run on.

1. Open Settings → Advanced.
2. Under Providers, tap the one you want and fill in its fields. Google needs a key, Cloudflare also wants your Account ID, and Custom wants an endpoint URL and a default model.
3. Test connection. A tiny text prompt goes to that provider using your key, so passing means the key and the endpoint work. Whether a model can read an image is a separate question, answered in step 5.
4. Save. It stays locked until a test passes on exactly the values on screen, which is deliberate: a saved key that has never worked would fail at the worst possible moment. The row then reads Working.
5. Under AI tools, open Receipt scan and give it a provider and a model. Test this model is worth using here: on a scan it runs a real test receipt and tells you how many items it read back, which is the only thing that proves the model can actually see. Unlike the key sheet, this one won’t stop you saving an untested choice.
6. Turn on Use my own AI key. It sits at the top of the screen, above both lists, but it stays greyed out until at least one provider tests as working, which is why it is the last thing you do rather than the first.

A provider row tells you where it stands: Not set, Untested, Working or Failed, and once it works, which tools are pointed at it. A tool row shows its provider and model underneath, or Not set up if it has neither yet.

• The test fails and mentions 401 or 403. The key is wrong, expired, or restricted to something else. Make a new one and paste it again. Google AI Studio is the odd one out and answers a bad key with a 400, which the app spells out for you.
• A brand new Google key is refused straight away. Google changed the kind of key AI Studio issues during 2026, and the changeover has been bumpy. Check Google’s AI Developer Forum before assuming you did something wrong, and try one of the other providers meanwhile.
• 429, or anything about rate limits. You’ve reached the free allowance. Wait it out, or go back to Settings → Advanced, open Receipt scan, and point it at another provider you’ve set up. Nothing switches provider on its own.
• Cloudflare says the Account ID looks wrong. It’s 32 hex characters, 0 to 9 and a to f. The Zone ID and the token’s own id are different values.
• A custom endpoint keeps returning 400. If the endpoint says the problem is the response format, FairThen retries in plain JSON mode by itself. Any other 400 is final, so the model most likely can’t return structured JSON, or, on Receipt scan, can’t read images at all.
• It worked yesterday and doesn’t today. Providers retire models. When that happens the provider is marked Failed and stops being used, rather than quietly falling back to something that can’t work. Worth knowing: if the provider that broke is the one behind Receipt scan, then Use my own AI key switches itself off. Sort the key out or point Receipt scan at another provider, then switch it back on. We can point the app at a replacement model without an app update, though it only looks for one about once a week, so reopen the tool, choose a model again and Test this model, or use Custom with a model id you choose yourself.
• Still stuck. Email support@fairthen.com. We can’t see anything that happened on the provider’s side, but we can usually tell you whether the app is doing its part.