Freiberufler / Einzelunternehmen

Create a tax registration for a freelancer or sole proprietor. Generates the ELSTER FsE_EUn form.

POST https://api.beglaubigt.de/v1/tax-registration

The request for a Freiberufler or Einzelunternehmen (freelancer or sole proprietor). legal_form is einzelunternehmen, which maps to the ELSTER FsE_EUn form. There is no company entity: the taxpayer is the owner, and the client company is named after them.

Authorization

Include an Authorization header with a Bearer token:

Authorization: Bearer <token>

Example: Bearer sk-123e4567-e89b-12d3-a456-426614174000

Environment

The environment comes from the company your API key belongs to, not from the request. A sandbox company's key creates sandbox registrations, filed against the ELSTER test environment; a production company's key creates live ones. To test, use the API key of your sandbox company.

The example tax ID 09481663279 is ELSTER's test IdNr: the sandbox accepts it, and production rejects it with 400 VALIDATION_ERROR. A production registration needs each person's real tax ID.

Idempotency

To retry a request safely after a timeout or a 5xx, send an Idempotency-Key header and reuse the same key on every retry. A retry then gets the first response back instead of creating a second case. See Idempotency.

Idempotency-Key: 5b0c8e8a-7d2f-4d0e-9a51-1f0b6a4c2e11

Request

Core

company_idstring

The UUID of the client company the tax registration belongs to. A company holds at most one tax registration and one trade registration, so use the same company_id on both endpoints to keep a client's registrations together, in parallel or in any order.

A UUID that does not exist yet: the company is created under that id. You can choose the id yourself.
An existing company of yours: the registration is added to it. If it already has a tax registration, the request returns 409 COMPANY_ALREADY_REGISTERED. If it is in another environment than your API key's company (see Environment), it returns 409 ENVIRONMENT_MISMATCH.
A company created by another account: 404 COMPANY_NOT_FOUND.
Omitted: a new company is created and its id returned as company_id.

Example: 9b2e4c7a-1d3f-4a8b-9c6e-2f5a7b8c1d0e

business_addressobject

Billing address of the client company created for you. Only applies when company_id is omitted; it is rejected if sent together with company_id.

legal_formstringrequired

The legal form.
Possible values: einzelunternehmen

packagestringrequired

The service package the client selected.
Possible values: self or assisted (guided is still accepted as a deprecated alias of assisted)

signature_pathstringrequired

The client's signature as an SVG path string (the drawn signature).
Example: M 10 10 L 90 90 M 90 10 L 10 90

client_referencestring

A custom reference string for your own tracking.
Example: REF-2025-001

Business

purposestringrequired

Description of the business activity. Max 200 characters.
Example: Freiberufliche IT-Beratung

operational_activity_start_datestringrequired

The date the business begins operating. Format: YYYY-MM-DD.
Example: 2025-04-01

Owner & Address

ownerobjectrequired

The natural person behind the sole proprietorship (Inhaber).

address_same_as_homebooleanrequired

Whether the business address equals the owner's home address.
Possible values: true or false

addressobjectrequired

Business address, required when address_same_as_home is false (see the Address object).

Bank Account

ibanstring

The owner's business bank account IBAN. For a non-German IBAN you must also supply bic.
Example: DE89370400440532013000

bicstring

The bank identifier (BIC/SWIFT) for the account, 8 to 11 characters. Required for non-German IBANs.
Example: COBADEFFXXX

Revenue & Profit Estimates

financial_estimatesobjectrequired

Estimated revenue and taxable profit for the formation year and the following year. All amounts are whole euros.

formation_yearobjectrequired

Estimates for the formation year (the year the business starts operating).

following_yearobjectrequired

Estimates for the year after the formation year.

VAT

Freelancers (Freiberufler) are always taxed on a cash basis (Ist-Versteuerung, § 20 UStG), so vat.accounting_method does not apply to this form.

vatobjectrequired

The company's VAT setup.

regimestring

The VAT regime the company elects. small-business elects the small-business exemption (Kleinunternehmer, § 19 UStG); standard is the regular VAT regime (Regelbesteuerung). Required when the election is available (founding-year revenue ≤ €25,000; the following-year estimate does not affect it). Above €25,000 the business is on the regular VAT regime regardless: omit the field or send standard. small-business fails there with 400, because it rules out vat.estimated_balance_type and vat.estimated_balance_amount, which are then required.
Possible values: small-business or standard

estimated_balance_typestring

Whether you expect to owe VAT to the tax office (payable, Zahllast) or receive a refund (refundable, Überschuss). Required unless you are a small business (Kleinunternehmer): that is, when vat.regime is standard, or founding-year revenue is more than €25,000.
Possible values: payable or refundable

estimated_balance_amountnumber

Estimated net VAT amount for the year, either payable or refunded. Required with estimated_balance_type.
Example: 4000

return_frequencystring

How often VAT returns are filed. Required for an input-VAT surplus (Vorsteuerüberschuss, estimated_balance_type = refundable) greater than €9,000, where only monthly is valid; quarterly is the tax office's default.
Possible values: monthly or quarterly

request_vat_idboolean

Whether to request an EU VAT identification number (USt-IdNr), used for cross-border B2B trade.
Possible values: true or false

sells_via_online_marketplacesboolean

Whether you sell through online marketplaces such as Amazon or Etsy (§ 25e UStG record-keeping).
Possible values: true or false

request_reverse_charge_certificateboolean

Whether to apply for the reverse-charge certificate for construction and building-cleaning services (USt 1 TG, § 13b UStG). When true, reverse_charge_service_type is required.
Possible values: true or false

reverse_charge_service_typestring

The type of service the reverse-charge certificate covers. Required when request_reverse_charge_certificate is true.
Possible values: construction, building-cleaning or both

Employees & Payroll

has_employeesboolean

Whether there are employees. Enables the payroll block. When true, the fields below are all required.
Possible values: true or false

employee_countnumber

Number of employees. Required when has_employees = true.
Example: 3

payroll_start_datestring

Start of wage payments. Must not be before operational_activity_start_date. Required when has_employees = true. Format: YYYY-MM-DD.
Example: 2025-06-01

estimated_annual_wage_taxnumber

Estimated annual wage tax (Lohnsteuer). Required when has_employees = true.
Example: 6000

Shared Objects

Addressobject

Response

A self registration is filed with ELSTER within the request. A request that fails validation, or that ELSTER refuses, is an error and creates nothing. An assisted one is reviewed by a lawyer before it is filed.

resultstring

Outcome of the request.
Possible values: success or error

messagestring

Human-readable outcome message.
Example: Tax registration filed with ELSTER.

company_idstring

UUID of the client company the case belongs to: the company_id you sent, or the one created for you when you omitted it. Pass it as company_id to the trade registration endpoint to register the same company there.
Example: 9b2e4c7a-1d3f-4a8b-9c6e-2f5a7b8c1d0e

tax_registration_idstring

UUID of the tax registration case. Use it with the GET endpoint.
Example: 450506c1-d1a7-46e2-aca6-41a816805595

statusstring

How far the registration got.
Possible values:

submitted: filed with ELSTER. transfer_ticket and documents are set.
validated: an assisted registration, waiting for the lawyer's review before it is filed.
blocked: rare. The filing failed in a way that may have reached ELSTER, so the case is kept and our team checks it with ELSTER and finishes it; the tax-registration.completed webhook and the GET endpoint report the result. Nothing to resend.

tax_officeobject

The tax office (Finanzamt) the registration is filed with, resolved from the address.

transfer_ticketstring

ELSTER's receipt for the filing, present when status is submitted.
Example: et1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d

documentsobject

Download links for the filing's PDFs, present when status is submitted. Each link is valid for 24 hours; the GET endpoint returns fresh ones.

timestampstring

ISO 8601 timestamp of the response.
Example: 2025-02-01T07:19:30.443Z

Errors

Status	`error_code`	When	Created
`400`	`VALIDATION_ERROR`	A field is missing or invalid. `details` lists each field with its problem.	Nothing
`401`	(none)	The API key is missing or invalid. The body is `{ "error": "Unauthorized: Missing or invalid token" }`.	Nothing
`404`	`COMPANY_NOT_FOUND`	The `company_id` you passed belongs to another account.	Nothing
`409`	`COMPANY_ALREADY_REGISTERED`	The `company_id` you passed already has a tax registration.	Nothing
`409`	`ENVIRONMENT_MISMATCH`	The `company_id` you passed belongs to a different environment than your API key.	Nothing
`422`	`FINANZAMT_NOT_FOUND` / `VALIDATION_ERROR`	No tax office matches the address, or the dates are out of order.	Nothing
`409`	`IDEMPOTENCY_REQUEST_IN_PROGRESS`	A request with the same `Idempotency-Key` is still running. Retry with the same key.	Nothing
`422`	`IDEMPOTENCY_KEY_REUSED`	The `Idempotency-Key` was already used with a different request body.	Nothing
`422`	`ELSTER_PLAUSIBILITY_ERROR`	ELSTER refuses the registration. `details` names each field to fix and what ELSTER needs.	Nothing
`500`	`PROCESSING_ERROR`	An error on our side. Contact support with the `timestamp`.	Nothing

Example

Request

{
  "legal_form": "einzelunternehmen",
  "package": "self",
  "signature_path": "M 10 10 L 90 90 M 90 10 L 10 90",
  "purpose": "Freiberufliche IT-Beratung",
  "operational_activity_start_date": "2025-04-01",
  "owner": {
    "first_name": "Max",
    "last_name": "Mustermann",
    "dob": "1985-07-10",
    "profession": "IT-Berater",
    "tax_identification_number": "09481663279",
    "religion": "11",
    "address": {
      "street": "Schweizer Strasse 8",
      "street_second_line": "2. Etage",
      "zip": "60594",
      "city": "Frankfurt am Main",
      "country": "de"
    }
  },
  "address_same_as_home": true,
  "vat": {
    "regime": "small-business"
  },
  "financial_estimates": {
    "formation_year": { "revenue_amount": 20000, "profit_amount": 18000 },
    "following_year": { "revenue_amount": 35000, "profit_amount": 30000 }
  }
}

Response

{
  "response": {
    "result": "success",
    "message": "Tax registration filed with ELSTER.",
    "company_id": "9b2e4c7a-1d3f-4a8b-9c6e-2f5a7b8c1d0e",
    "tax_registration_id": "450506c1-d1a7-46e2-aca6-41a816805595",
    "status": "submitted",
    "tax_office": { "number": "2614", "name": "Frankfurt am Main" },
    "transfer_ticket": "et1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d",
    "documents": {
      "questionnaire_url": "https://app.beglaubigt.de/download?bucket=company-documents&id=3f1c2b9e-7d4a-4c1e-9b2f-5a8d6e7f9c0b&token=a1H...To5",
      "confirmation_url": "https://app.beglaubigt.de/download?bucket=company-documents&id=8a2d4e6f-1b3c-4d5e-8f9a-0b1c2d3e4f5a&token=b2J...Up6"
    },
    "timestamp": "2025-02-01T07:19:30.443Z"
  }
}

Freiberufler / Einzelunternehmen

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