Calculate tax for a source — TaxMaxi Sources API

Once a source has a completed sync, you can calculate its tax liability for any year and jurisdiction. TaxMaxi applies FIFO (first-in, first-out) accounting to your normalized transaction records and returns a breakdown of gains, losses, and income. The calculation runs on demand each time you call the endpoint, so you can re-run it after a replay or for different years without any additional setup. Required header: Authorization: Bearer <token>

TaxMaxi provides tax calculation results for informational purposes only. The output of this API is not tax advice. You should consult a qualified tax professional before filing any tax return.

Calculate tax

Calculates jurisdiction-specific tax figures from normalized FIFO and income data for the specified source.

POST /v1/sources/:sourceId/tax

The source must have a sync with status: "completed" before you call this endpoint. If the source has never been synced or the most recent sync failed, the API returns a 404.

Path parameters

string

required

The ID of the source to calculate tax for.

Request body

integer

required

The tax year to calculate. Must be between 1970 and the current year (inclusive).

string

required

The tax jurisdiction to apply. Currently supported: "germany".

Response fields

number

required

The tax year the calculation applies to.

string

required

The base currency in which all monetary values are expressed (e.g. "EUR").

number

required

Net gains from crypto assets held for less than one year. These are subject to income tax in Germany.

number

required

Net losses from crypto assets held for less than one year. These can offset taxable gains.

number

required

Gains from crypto assets held for more than one year. Under German tax law, these gains are tax-free.

number

required

Total income from non-trade events such as staking rewards, airdrops, and other income-classified transactions.

Errors

Status	Code	Description
`400`	`SourceBadRequestError`	The request body is missing required fields or contains invalid values.
`404`	`SourceNotFoundError`	No source was found for the given ID, or the source has not completed a sync.
`500`	`InternalServerError`	An unexpected server error occurred.

Example

curl --request POST \
  https://api.taxmaxi.com/v1/sources/src_01hzqe3kj8t2v5n6b7d9f0gx/tax \
  --header "Authorization: Bearer <token>" \
  --header "Content-Type: application/json" \
  --data '{
    "year": 2024,
    "jurisdiction": "germany"
  }'

Response

{
  "year": 2024,
  "currency": "EUR",
  "taxableGains": 4250.80,
  "taxableLosses": 310.50,
  "taxFreeGains": 12000.00,
  "incomeTotal": 875.25
}

Understanding the response

Field	Description
`taxableGains`	Gains from selling or swapping crypto held for less than 12 months. In Germany, these are taxed as income.
`taxableLosses`	Losses from assets held less than 12 months. You can offset these against taxable gains in the same year.
`taxFreeGains`	Gains from assets held for more than 12 months. German tax law exempts these from taxation.
`incomeTotal`	The total value received from staking rewards, airdrops, and similar income events at the time of receipt.

All values are in the base currency returned in the currency field.

​Calculate tax

​Path parameters

​Request body

​Response fields

​Errors

​Example

​Understanding the response

Calculate tax

Path parameters

Request body

Response fields

Errors

Example

Understanding the response