Count message tokens

Endpoint
POST/v1/messages/count_tokens

Compatible with the Anthropic count_tokens API. The request body matches Create a message without max_tokens; it only counts, generates no reply, and produces no output tokens.

Request

Same headers as Create a message: x-api-key (or Authorization: Bearer), anthropic-version: 2023-06-01, and content-type: application/json.

json
{
  "model": "claude-sonnet-5",
  "messages": [
    {"role": "user", "content": "Introduce yourself in one sentence"}
  ]
}

Parameters

Field Type Required Notes
model string Yes Claude model ID
messages array Yes The messages to count, in the same format as Create a message
system string or array No System prompt, included in the count

Response

json
{"input_tokens": 16}
Field Notes
input_tokens Tokens these messages occupy as input

Examples

bash
curl https://api.moyiapi.com/v1/messages/count_tokens \
  -H "x-api-key: sk-moyiapi-xxxxxx" \
  -H "anthropic-version: 2023-06-01" \
  -H "content-type: application/json" \
  -d '{
    "model": "claude-sonnet-5",
    "messages": [{"role": "user", "content": "Introduce yourself in one sentence"}]
  }'

Errors

HTTP status error.type When it happens
401 missing_auth_credential / invalid_api_key / invalid_bearer_token Authentication failed; see Authentication
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Count message tokens · Docs