How to get your own AI key

ContoTrip works on a bring-your-own-key basis: AI receipt recognition runs through an account that you set up yourself with one of the three AI providers. That is the only real hurdle when getting started – and this guide clears it out of the way. It takes about ten minutes and no programming knowledge at all.

This guide reflects the situation on 3 September 2026. The providers rebuild their websites regularly. The steps below therefore describe what you want to achieve, not how a button happens to be labelled today. If something is named differently on your screen: the order create an account → add a payment method → generate a key holds for all three.

What an API key is

An API key is a long, random string of characters that identifies you to a provider – a password for programs instead of for people. The abbreviation “API” stands for the interface through which two programs talk to each other.

Once you enter the key in ContoTrip, the app is allowed to talk to the provider on your behalf, and whatever that costs is billed to your account with them. You do not have to write any code: generate the key on the provider’s website, copy it, paste it into ContoTrip – done.

Why you need a key of your own

Because there is no ContoTrip backend. When you use an AI feature, the request goes straight from your iPhone to the provider you picked, and the answer comes back the same way. There is no stop in between where your receipt photo could be left behind.

A shared key for all users would rule that out: such an account would need a server between you and the provider passing every request along – and that server could read along. Your own key is the price of that place not existing. As a side effect you pay only for what you actually use, and nobody adds a margin on top.

The key itself is kept in the iOS keychain – the encrypted store of the system, the same place your passwords live. Not in the ordinary app settings, whose values can be read out, and it is never transmitted to us.

The app only ever talks to the address of the provider you chose:

• OpenAI: https://api.openai.com/v1
• Google Gemini: https://generativelanguage.googleapis.com/v1beta/openai
• Anthropic: https://api.anthropic.com/v1

The three providers compared

All three deliver good results for what ContoTrip asks of them. What differs is how much work it takes to get started and what it costs.

For a first key we recommend Google Gemini. Once you accept the terms of use, Google AI Studio sets up everything else for you according to Google’s own documentation – you have the key within minutes. For getting started there is a free tier there, and it asks for no payment method.

One point belongs with that recommendation: on the free tier Google reserves the right to use the content you send to improve its products – with ContoTrip that would be your receipt photos, including the merchant, the amounts and everything else printed on the slip. On the paid tier Google rules that use out; for it you add a payment method. Both are openly documented and both are a legitimate choice – you should simply know which one you are making.

If you scan a lot of receipts and watch the cost, OpenAI is the cheapest of the three; Anthropic Claude sits in between. You can switch at any time: in ContoTrip you simply replace provider and key in the settings, and nothing else changes.

Step by step: Google Gemini

1. Open aistudio.google.com/apikey and sign in with your Google account.
2. Accept the terms of use. Google AI Studio then automatically creates a Google Cloud project and a key for you – that part needs no attention from you.
3. Copy the key and keep it somewhere safe. Providers usually show a freshly created key in full exactly once.
4. Set up a budget alert in the Google Cloud console. Google recommends this itself, and it is the simplest brake against surprises.

Step by step: Anthropic Claude

1. Create an account at platform.claude.com. If you come across the older address console.anthropic.com somewhere: it redirects to the same place.
2. Add a payment method and top up some credit at platform.claude.com/settings/billing.
3. Generate a new key at platform.claude.com/settings/keys and copy it right away.
4. Take a look at platform.claude.com/settings/limits. Anthropic works with usage tiers; that page shows which spending limits apply to your account.

Step by step: OpenAI

We describe this route in general terms on purpose – the interface changes more often than a written guide can follow.

1. Create an account at platform.openai.com.
2. Add a payment method or top up credit in the billing area. Without that, a key you generate stays without effect.
3. Generate a new key in the API keys area and copy it right away.
4. Where your account offers spending limits, set a monthly one.

What it costs

As long as you do not use receipt recognition, the account costs nothing – billing is per request. Unlike a plain text request, ContoTrip sends an image: the receipt photo. All three providers count images considerably more heavily than a few lines of text, so a receipt costs more than a short text prompt.

As an order of magnitude, a single receipt on the cheap models of the three providers sits somewhere between fractions of a cent and a few cents. That is a rough guide, not a promise: prices and models change, a large, densely printed photo costs more than a small till receipt, and the exchange rate has a say as well. What counts is your provider's price list – and the billing happens there, not through ContoTrip and not through the App Store. The purchase price of ContoTrip Pro does not include any AI usage.

In practice: set a spending limit with your provider before you start. That gives you the ceiling without having to keep the price list in your head.

Entering the key in ContoTrip

1. Open the settings in ContoTrip.
2. Choose the provider you created the key with.
3. Paste the key.
4. Run the connection test.

If the test reports an error it is almost always one of three things: the provider selected belongs to a different key, a character was lost while copying, or the payment method with the provider is still missing. Once the test passes, AI receipt recognition is ready to go.

Without a key the whole rest of the app stays fully usable – tasks, categories, reminders, widget and sync need no AI at all.

Security: treat the key like a password

• Do not pass it on – not in a chat, not as a screenshot, not in a support request. We will never ask you for it either.
• Set a spending limit or a budget alert with the provider. That is the most effective precaution should a key ever go astray.
• Look into the usage overview of your account now and then. Consumption you cannot explain is the first warning sign.
• If in doubt: revoke the key with the provider, generate a new one and replace it in ContoTrip. A revoked key is worthless the moment you revoke it.
• If you no longer need the AI features, remove the key in the app settings and revoke it with the provider as well.

If any questions remain, our support page will help.