BYOK or hosted credits: which Mathend agent should you use?

There are two ways to run the Mathend agent, and the right one depends on a single question: do you already have an API key you are happy paying for?

Bring your own key

Paste a key from Anthropic, OpenAI, Google, Zhipu, DeepSeek, xAI, Mistral, Groq or OpenRouter — or connect GitHub Copilot through its device flow — and the agent talks to that provider directly from your machine. No Mathend account, no balance, no middleman. You are billed by the provider at their rates, and we never see the traffic.

This is the cheapest option if you already pay for a model, and the only option if your organisation requires that requests go to a provider you have a contract with.

Hosted agent credits

If you do not want to manage a key, buy credits instead. Requests go through our gateway, which bills you the model’s cost plus a small per-model margin and deducts it from a prepaid balance. Packs are $5, $10 and $25. There is no subscription and no seat count, and unused credits never expire.

Fourteen models are available in three tiers, from cheap edit-and-format work up to the frontier models worth paying for on a hard derivation. The pricing page publishes the exact per-million-token rate for each one, generated from the same catalogue the gateway bills from.

Which to pick

Already paying for Claude or ChatGPT’s API? Bring your own key. Want to try the agent in the next sixty seconds without creating an account anywhere else? Buy $5 of credits. Either way the editor itself stays free.