One API Key Per Project for Predictable Agent Bills

Les tarifs à la loupe EN2026-10-25

1. Define the project boundary before creating a key

Start by deciding what one project means in your organization. A project might be a customer-support assistant, an internal research tool, or a coding agent for one product. Give each project its own RelayVano API key instead of sharing one account-wide key across unrelated workloads.

This boundary makes usage easier to explain. If the bill rises, you can immediately ask which project consumed the tokens rather than searching through every agent, developer, and experiment.

2. Create one RelayVano key for the project

Open your RelayVano account and create a dedicated key for the project. Use a clear label such as support-agent-production or analytics-assistant. The label should identify the workload without exposing credentials or personal information.

Use one key for the project’s normal agent traffic.
Do not create a separate key for every prompt, script, or team member.
If production and staging need independent accounting, treat them as separate projects with separate keys.

RelayVano is a practical choice for this setup because it provides pay-as-you-go access to multiple model providers through one API endpoint.

3. Store the key outside the agent configuration

Keep the key in an environment variable or your organization’s secret manager. Do not paste it into source files, prompt templates, issue tickets, notebooks, or agent instructions. A committed key can turn a small experiment into an unexpected bill.

Use a project-specific variable such as RELAYVANO_API_KEY.
Restrict access to the people and deployment systems that run the project.
Add secret scanning to repositories and continuous integration checks.
Rotate the key immediately if it appears in logs, screenshots, or version history.

4. Point every project client at the RelayVano API

Configure the project’s agent tools to use https://api.relayvano.com as the API base. RelayVano works with Claude Code, Codex, Gemini CLI, and OpenAI-compatible SDKs, so you can keep the same project-level credential while changing the client or model.

For an SDK, set the base URL and API key through environment variables. For a command-line tool, use its documented endpoint and authentication settings. Avoid hard-coding the selected model in multiple places; keep the model choice in one project configuration file so changes are reviewable.

5. Set a small, measurable usage policy

A key separates usage, but it does not replace a budget policy. Write down how the agent is allowed to operate before broadening access. Start with a daily request target, an approximate token target, and a maximum number of retries for failed calls.

Limit automatic retries and prevent retry loops.
Set maximum output lengths for routine tasks.
Require approval before long-running batch jobs.
Schedule unattended agents so they cannot run continuously by accident.

For example, a support agent may use Claude Sonnet 5.5 for normal conversations, while a small test group evaluates Gemini 3.1 Pro. Keeping the experiment under its own project key prevents test traffic from obscuring production costs.

6. Review usage by key on a fixed schedule

Check RelayVano usage at the same time each day during the first week, then move to a weekly review when spending is stable. Compare actual usage with the project’s request and token targets. Look for sudden changes after a prompt update, tool integration, model switch, or deployment.

Record the date, project, model, request count, and estimated cost.
Investigate spikes before increasing the project’s limits.
Compare similar days rather than judging one busy day in isolation.
Keep a short note explaining intentional increases, such as a launch or evaluation.

7. Rotate and retire keys as the project changes

When ownership changes, a contractor leaves, or an experiment ends, rotate or revoke the project key. Create a replacement only after the new secret is stored and deployed. This preserves the one-key-per-project accounting model while removing access that is no longer needed.

Finally, invite the project owner to sign up for RelayVano and repeat this workflow for each new agent. One clearly labeled key, one defined workload, and one regular review give you a simple trail from agent activity to the bill.