USDC Top-Up to First Successful Call: Validating Your Key Before You Commit Balance

Why Smoke Test First

Topping up USDC before confirming your key works risks locking funds into a setup that may fail on first use. A smoke test—a series of minimal API calls—verifies authentication, endpoint reachability, and billing behavior without large expenditure. This is especially important in a prepaid, no-KYC environment where you control the balance.

Prerequisites

• A funded balance (start with a small USDC top-up on Base).
• Your API key from the dashboard.
• Access to a command-line tool like curl or an HTTP client.
• The list of supported models and their exact identifiers from the documentation.

Step 1: Top Up a Minimal Amount

Send a small USDC amount on Base to the provided deposit address. Wait for confirmation; your balance should reflect the top-up. This amount should cover several tiny calls across backends—enough to test without over-committing.

Step 2: Prepare a Minimal Request Payload

For each backend, craft a request with the smallest possible token count:

• Use a short prompt (e.g., "Hello").
• Set max_tokens to 1 (or the minimum allowed).
• Use the correct model identifier (e.g., claude-3-haiku, gpt-4o-mini, deepseek-chat, etc.).

Example curl for an OpenAI-compatible endpoint:

curl -X POST https://api.example.com/v1/chat/completions \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"gpt-4o-mini","messages":[{"role":"user","content":"Hello"}],"max_tokens":1}'

Step 3: Execute One Call per Backend

Run the minimal request against each backend you plan to use. Focus on:

• HTTP status code: Expect 200 OK. A 401 indicates an auth issue; 404 may mean a wrong endpoint or model; 429 suggests rate limiting (unlikely on first call).
• Response body: Ensure it contains a valid completion (even if truncated).
• Error messages: Check for clues if the call fails.

Record the status and any error details.

Step 4: Verify Billing Deduction

After each call, check your balance via the dashboard or API. The deduction should equal the official price × 1.3 for the tokens used. Because the call is tiny, the amount will be minimal—confirm it matches expectations. This validates that billing works and your balance is correctly decremented.

Step 5: Interpret Results and Adjust

• All calls succeed, billing correct: Your key is valid, and you can top up more USDC with confidence.
• Some calls fail: Check the model identifier, endpoint URL, and key permissions. Retry after fixing.
• Billing discrepancy: Contact support with the request IDs; do not proceed until resolved.

Step 6: Scale Up

Once the smoke test passes, increase your top-up and begin using the API in earnest. Remember that contributors earn credits at official price × 1.1 (or × 1.2 for premium models), which can offset costs if you share keys.

Best Practices

• Always test new backends with a minimal call before integrating.
• Keep a small buffer balance for smoke tests.
• Monitor status codes and billing regularly.
• Use environment variables for API keys to avoid exposure.

By following this sequence, you confirm your key works and billing is accurate before committing larger sums—ensuring a smooth start with the API aggregator.