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Using Your Own OpenAI API Key in an iOS App (PensionBud Guide)

PensionBud includes a lightweight AI helper to explain pension scenarios in plain English.

However, AI services like OpenAI come with usage costs — and rather than limiting users completely, PensionBud gives you the option to use your own OpenAI API key.

This gives you full control over usage, cost, and access.

Why PensionBud offers this option

Running AI services at scale can be expensive. Instead of restricting features entirely, PensionBud uses a hybrid approach:

• A small shared AI allowance for basic use
• The option to connect your own OpenAI API key for extended usage

What is an OpenAI API key?

An API key is a secure token that allows your app to communicate with OpenAI’s services.

It identifies your account and tracks usage for billing.

You can create one via the OpenAI platform:

Create an OpenAI API key →

How PensionBud uses OpenAI

PensionBud sends structured prompts to OpenAI to:

• Explain pension scenarios
• Break down trade-offs (e.g. drawdown vs annuity)
• Answer follow-up questions in plain English

Importantly:

• No personal data is required to use the app
• You control what information you choose to enter

Example API request (simplified)

Here’s a simplified example of how an app might call OpenAI:

POST https://api.openai.com/v1/chat/completions

Headers:
Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

Body:
{
  "model": "gpt-4.1-mini",
  "messages": [
    {"role": "system", "content": "Explain pension scenarios clearly."},
    {"role": "user", "content": "Can I retire at 57 with £750k?"}
  ]
}

The response is then displayed inside the app.

How to use your API key in PensionBud

The process is simple:

1. Create an API key via OpenAI
2. Copy the key
3. Paste it into PensionBud’s AI settings

Once added, your requests are routed through your own OpenAI account.

Cost control and transparency

Using your own API key means:

• You pay OpenAI directly for usage
• You can monitor usage in your OpenAI dashboard
• You can stop usage at any time

This avoids hidden subscriptions or bundled costs.

Security best practices

API keys should always be treated like passwords.

Best practices include:

• Do not share your key publicly
• Rotate keys if you believe they are compromised
• Use usage limits within OpenAI where possible

Why this approach matters

Many apps either:

• Hide AI costs behind subscriptions
• Limit usage heavily

PensionBud takes a different approach:

• Give users a small amount of AI access
• Let power users bring their own API access

This keeps the app accessible while still offering flexibility.

Final thought

AI is a powerful tool — but it works best when users understand how it’s being used.

By allowing you to connect your own OpenAI API key, PensionBud keeps things simple, transparent, and in your control.

This article is for general information only. OpenAI services are subject to their own pricing and terms.