Bring Your Own Keys

The Problem with AI Subscriptions

Most AI apps charge $20-30 per month. Every month. Whether you use them heavily or barely at all.

Behind the scenes, they're making API calls to OpenAI or Anthropic that cost them pennies. The subscription model exists because it's profitable for them—not because it's fair to you.

You're paying for:

• Their server infrastructure
• Their profit margin
• Their other users who use more than you
• Features you might never touch

There's a better way.

What BYOK Actually Means

Bring Your Own Keys (BYOK) flips the traditional model. Instead of paying us to make API calls on your behalf, you connect directly to AI providers using your own account.

How it works:

1. Create a free account with an AI provider (OpenAI, Anthropic, Google, or xAI)
2. Generate an API key from their dashboard
3. Add that key to Postiller's settings
4. Your prompts go directly from your device to the provider

That's it. No middleman. No markup. No subscription.

The Real Cost of AI

Here's what AI actually costs at standard API rates:

Most personal users spend $1-5 per month on actual API usage. Compare that to $20-30 subscription fees.

The math doesn't lie: subscriptions are a 5-10x markup on actual costs.

Choose Your Provider

Different AI providers have different strengths. With BYOK, you're not locked into whoever we partnered with—you choose what works best for your content.

OpenAI (GPT-4o, GPT-4o-mini)

Best for: Nuanced writing, complex reasoning, following detailed instructions

GPT-4o produces polished, professional content. GPT-4o-mini is faster and cheaper for simpler tasks. Most users start here because they already have an OpenAI account.

Anthropic (Claude Sonnet, Claude Haiku)

Best for: Long-form content, maintaining consistent style, thoughtful analysis

Claude excels at following persona guidelines and producing content that sounds human. Haiku is extremely fast and cost-effective for quick drafts.

Google (Gemini Pro, Gemini Flash)

Best for: Speed, cost-efficiency, everyday content generation

Gemini Flash is one of the fastest models available. Great for iterating quickly on drafts without watching costs.

xAI (Grok)

Best for: Current events, unfiltered perspectives, conversational tone

Grok has real-time knowledge and a more casual, witty style. Good for content that references recent happenings.

Your Keys Stay Secure

API keys are sensitive. Here's how Postiller protects them:

Encrypted storage — Keys are stored in your device's secure keychain, encrypted at rest. They're never stored in plain text.

Direct transmission — When you generate content, your prompt goes directly from your device to the AI provider over HTTPS. It never touches our servers.

No server-side storage — We don't have a database of user API keys. We couldn't access them even if we wanted to.

You control access — You can revoke or rotate your keys anytime through the provider's dashboard. Postiller just uses whatever key you've provided.

Setting Up Your Keys

Getting started takes about 5 minutes per provider:

OpenAI

1. Go to platform.openai.com
2. Create an account or sign in
3. Navigate to API Keys in the sidebar
4. Click "Create new secret key"
5. Copy the key and paste it into Postiller's settings

You'll need to add a payment method, but you're only charged for what you use. Set a monthly limit if you want to cap spending.

Anthropic

1. Go to console.anthropic.com
2. Create an account or sign in
3. Navigate to API Keys
4. Create a new key
5. Add to Postiller

Google AI

1. Go to aistudio.google.com
2. Sign in with your Google account
3. Get an API key from the settings
4. Add to Postiller

xAI

1. Go to x.ai
2. Create an account
3. Generate an API key
4. Add to Postiller

Mix and Match

Here's something subscription apps can't offer: use different providers for different tasks.

Postiller lets you assign specific models to specific tasks:

• Learnings extraction → Use a fast, cheap model (Gemini Flash)
• Post generation → Use your favorite writing model (Claude Sonnet)
• Embeddings → Use on-device (free, no API key needed)

This isn't just about cost optimization—different models genuinely produce different results. Experimentation is cheap when you're paying per-use.

The Trust Equation

When you use a subscription AI app, you're trusting them with:

• Your content and ideas (sent through their servers)
• Your money (recurring charges whether you use it or not)
• Your access (they can change pricing or features anytime)

With BYOK, trust is distributed:

• Your content → Goes directly to the AI provider you chose
• Your money → Pay-as-you-go, only for actual usage
• Your access → You own the API key relationship

We're not asking you to trust us with your data or your wallet. We're giving you the tools to maintain control yourself.

Why We Built It This Way

We could make more money with subscriptions. But we'd rather build something we'd actually want to use ourselves.

Subscriptions create misaligned incentives: the app profits whether or not you get value. BYOK means you only pay when you're getting results.

It's a simpler relationship. You buy the app once. You pay AI providers for actual usage. Everyone's incentives are aligned.

That's the kind of software we want to exist in the world.