How do I add billing to my FastAPI app?

Install the Commet SDK, add your API key, and start billing. Follow the [FastAPI integration guide](/docs/integrate-with-fastapi) for a step-by-step walkthrough with code examples.

Commet

Add billing with
FastAPI

Start billing for free Read docs

Built for FastAPI

Billing that fits your stack

FastAPI's dependency injection makes billing clean. Inject entitlement checks as dependencies, validate request bodies with Pydantic, and handle webhooks with type safety.

routes/billing.py

from fastapi import APIRouter
from commet_client import commet

router = APIRouter()

@router.post("/subscribe")
async def subscribe(email: str, customer_id: str):
    commet.customers.create(
        email=email,
        id=customer_id,
    )

    subscription = commet.subscriptions.create(
        customer_id=customer_id,
        plan_code="pro",
    )

    return {"checkout_url": subscription.data["checkout_url"]}

from fastapi import APIRouter
from commet_client import commet

router = APIRouter()

@router.post("/subscribe")
async def subscribe(email: str, customer_id: str):
    commet.customers.create(
        email=email,
        id=customer_id,
    )

    subscription = commet.subscriptions.create(
        customer_id=customer_id,
        plan_code="pro",
    )

    return {"checkout_url": subscription.data["checkout_url"]}

Get started

Install in seconds

Add billing to your FastAPI app with the Commet SDK. Async-ready endpoints for subscriptions, usage tracking, and webhooks.

Get started Documentation

Terminal

pip install commet-sdk fastapi

pip install commet-sdk fastapi

Frequently Asked Questions

Install the Commet SDK, add your API key, and start billing. Follow the FastAPI integration guide for a step-by-step walkthrough with code examples.

Commet supports metered (pay for what you use), credits (block when exhausted), balance (spend across features), seats (per-user pricing), and boolean (feature gating). Learn more in the consumption models guide.

Yes. Call the usage tracking method whenever a billable event happens. Commet aggregates usage and bills it at the end of each billing period. Works for API calls, AI tokens, storage, or any custom metric. See the usage tracking guide for details.

Yes. Commet has a built-in AI model catalog with per-token pricing. You can track input, output, and cache tokens with configurable margins. See the AI token billing guide for setup instructions.

Yes. Commet is a Merchant of Record that handles taxes, compliance, refunds, and payouts. Stripe Tax is integrated for automatic tax calculation. Read more about the Merchant of Record model.

Commet has no setup fees and no monthly minimums. You only pay 4.5% + $0.40 per successful transaction. You can start building and testing for free using the sandbox environment. See pricing for details.

Start billing in minutes

No setup fees. No monthly minimums. 4.5% + $0.40 per successful transaction.

Start billing for free

from fastapi import APIRouter

from commet_client import commet

router = APIRouter()

@router.post("/subscribe")

async def subscribe(email: str, customer_id: str):

commet.customers.create(

email=email,

id=customer_id,

)

subscription = commet.subscriptions.create(

customer_id=customer_id,

plan_code="pro",

)

return {"checkout_url": subscription.data["checkout_url"]}

from fastapi import APIRouter

from commet_client import commet

router = APIRouter()

@router.post("/subscribe")

async def subscribe(email: str, customer_id: str):

commet.customers.create(

email=email,

id=customer_id,

)

subscription = commet.subscriptions.create(

customer_id=customer_id,

plan_code="pro",

)

return {"checkout_url": subscription.data["checkout_url"]}

Add billing withFastAPI

Billing that fits your stack

Install in seconds

Frequently Asked Questions

Start billing in minutes

Add billing withFastAPI

Billing that fits your stack

Install in seconds

Frequently Asked Questions

Start billing in minutes

Add billing with
FastAPI

Add billing with
FastAPI