POST /v1/messages/count_tokens

Counts input tokens without generating a response. This endpoint is free and does not consume the key RPM counter.

Request

curl https://api.model-gate.com/v1/messages/count_tokens \
  -H "x-api-key: mg_live_..." \
  -H "anthropic-version: 2023-06-01" \
  -H "content-type: application/json" \
  -d '{"model":"claude-opus-4.8","messages":[{"role":"user","content":"Hello"}]}'

Response

{"input_tokens":12}

Only input tokens can be estimated before generation. See Messages for the complete request body.