Count tokens in a message

Counts the input tokens a Messages request would consume, without calling a model.

Also served at /v1/anthropic/v1/messages/count_tokens; both paths accept the same requests.

AuthorizationBearer

Your production key sent as a bearer token.

This endpoint expects an object.

modelstringRequired

messageslist of objectsRequired

systemstring or list of objects or nullOptional

toolslist of objects or nullOptional

Successful Response

input_tokensinteger

422

Unprocessable Entity Error

$	curl -X POST https://api-gateway.merge.dev/v1/messages/count_tokens \
>	-H "Authorization: Bearer <token>" \
>	-H "Content-Type: application/json" \
>	-d '{
>	"model": "anthropic/claude-sonnet-5",
>	"messages": [
>	{
>	"role": "user",
>	"content": "What is the capital of France?"
>	}
>	]
>	}'