When buying direct is cheaper
If you only use one lab's models, buying prepaid credits from that lab costs face value, with no top-up fee. On $1,000 of usage, that's $55 less than OpenRouter by card. You also get the lab's own features first (batch APIs, caching options, new models on day one).
When OpenRouter is worth it
If you switch between Claude, GPT, Gemini and open models, one key and one balance save you from managing several accounts, rate limits and invoices. Provider fallback keeps requests going when a host is down.
If you want the convenience without the fee, discount credit books (smaaart, Orbio) resell OpenRouter usage below face value, within their depth. See the main comparison.
Want the whole field? See the live comparison or estimate your bill with the cost calculator.