Count tokens
Count the number of input tokens an Anthropic-format Messages request would consume, without generating a message.
POST /messages/count_tokens
Count input tokens for an Anthropic-compatible Messages request.
Parameters
Header parameters
| Field | Type | Required | Description |
|---|---|---|---|
anthropic-version | string | No | Anthropic API version header. Accepted for SDK compatibility. |
x-api-key | string | No | API key header used by Anthropic SDKs. Authorization: Bearer is also accepted. |
Request body
Content Type: application/json
Response
HTTP 200: Success
Content Type: application/json
python
import os
from anthropic import Anthropic
client = Anthropic(
base_url="https://api.meta.ai",
auth_token=os.environ["MODEL_API_KEY"],
)
message = client.messages.count_tokens(
model="muse-spark-1.3",
messages=[
{
"role": "user",
"content": "What is the capital of France?",
},
],
)
print(message.model_dump_json(indent=2))import json
import os
import requests
response = requests.post(
"https://api.meta.ai/v1/messages/count_tokens",
headers={
"Authorization": f"Bearer {os.environ['MODEL_API_KEY']}",
"Content-Type": "application/json",
},
json={
"model": "muse-spark-1.3",
"messages": [
{
"role": "user",
"content": "What is the capital of France?",
},
],
},
)
response.raise_for_status()
print(json.dumps(response.json(), indent=2))curl -X POST "https://api.meta.ai/v1/messages/count_tokens" \
-H "Authorization: Bearer $MODEL_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "muse-spark-1.3",
"messages": [
{
"role": "user",
"content": "What is the capital of France?"
}
]
}'For usage examples and rate-limit guidance that applies to the shared inference pipeline, see the Responses feature page.
Mirrored from dev.meta.ai/docs/api-reference/messages/count-tokens (synced Oct 30, 2026). Text and examples © Meta. Live demos run on Muse Muse's key.