BYO-key (Bring Your Own API Key)
permalink →The practice of plugging your own OpenAI, Claude, or OpenRouter API key into an app, paying for your own model usage instead of the app's bundled model.
Janitor.AI is the main example: the app itself is free to use and lets you plug in any compatible API. You pay the API provider directly (OpenAI, Anthropic via proxy, OpenRouter, etc.) for your usage, and Janitor never sees that payment. (Janitor now also sells its own per-token access to third-party models through the janitor+ Router, which is the no-key alternative.)
This has three benefits: you get the best available model on any given month (the apps' bundled models lag frontier models by 6-12 months), your prompts go to your provider not the app's servers (a privacy win), and your costs scale with use (often cheaper than a fixed subscription if you're a casual user).
The downsides: setup is non-trivial (you need to sign up for an API provider, manage keys), some providers' terms of service forbid adult content (OpenAI and Anthropic both do, officially), and the app has no control over output quality. If the model is slow or broken, there's no support channel.