What “Claude credits” usually means
Claude credits is a search phrase, not a single Anthropic product. On paid Claude plans it often means extra usage credits you can buy after the included usage limit. In Claude Code it can mean plan usage, extra usage, or a Console API key. On the Claude API / Workbench it means prepaid API credits billed in dollars against token usage. Promotional or startup credits are a fourth path with their own eligibility.
If you mix those wallets, extra usage on claude.ai will not refill an API key, and an API prepaid balance will not raise your chat plan limit. Pick the product first, then follow the official Settings or Console page for that product.