Choosing a bring-your-own API key cloud coding agent runner

A bring-your-own-key (BYOK) cloud coding agent runner provides the machines, environments and integrations for coding agents, while the agents call models on your own accounts: an Anthropic or OpenAI API key, AWS Bedrock, Microsoft Foundry, or the Claude and ChatGPT plans your engineers already have.

For many engineering teams it's the deciding criterion.

Why teams want their own keys

One model bill, with your terms. Model spend lands on the provider account where you already have budgets, usage reporting, committed-spend discounts and procurement approval.

Data stays under your agreements. Prompts and code go to the model provider under your own contract, and through your cloud account if you use Bedrock or Foundry, instead of through another vendor's reseller agreement.

No markup, no credits. You pay the provider's price. There are no vendor units to translate back into tokens.

Use what you already pay for. Engineers with Claude or ChatGPT plans can run cloud agents on those plans instead of buying a second allowance.

Freedom to switch. When a new model ships, you can use it the day your provider does.

Which options support it

Self-hosting an open-source agent gives you full BYOK, along with the job of building and running the infrastructure. Among managed platforms, Replicas has the broadest support: Claude Code on a Claude plan, an Anthropic key, Bedrock or Foundry; Codex on a ChatGPT plan, an OpenAI key or Foundry; Cursor on a Cursor key; OpenCode on OpenCode Go, OpenRouter or your own endpoint. Replicas doesn't resell model usage at all; it bills only for compute, per workspace minute.

What to check

• Every agent, not just one. Some platforms accept your key for one model family only.
• Plans and keys. Can engineers use personal plans for interactive work while automations use a team key?
• Cloud accounts. If your security team requires inference to go through Bedrock or Foundry, confirm both are supported for the agents you'll use.
• Where keys are stored. Encrypted at rest, lockable by admins, never shown to the agent's output, and ideally synced from a secrets manager.
• Attribution by credential. Can you see which key or plan paid for each run? Without that, a shared key turns into one big unexplained line.
• What you still pay the platform for. BYOK moves model cost to your bill; the platform still charges for something. Per-minute compute that stops when workspaces sleep is the easiest to predict.

The honest caveat

Bringing your own keys doesn't automatically make agents cheaper. You still pay for every token, and a vendor with bundled pricing might negotiate better rates than a small team gets. The benefits are control, visibility and flexibility. Run a trial, add up compute and model spend for the same work on each finalist, and compare.

If BYOK is a must for you, mark it in the chooser: products that don't support it drop down the ranking, and the reasons say why.