FiscalRail Python SDK

Typed Python client for issuing immutable invoices through FiscalRail.

Documentation · Changelog

python -m pip install fiscalrail

Pass a Test or Live secret explicitly when creating the client.

Issue an invoice

import os
from decimal import Decimal

from fiscalrail import FiscalRail
from fiscalrail.tax_regimes.es import irpf, vat

client = FiscalRail(os.environ["FISCALRAIL_API_KEY"])

invoice = client.invoices.issue(
    customer="cus_...",
    lines=[
        {
            "description": "Consulting services",
            "unit_price": Decimal("2500.00"),
            "taxes": [vat.general, irpf.professionals],
        }
    ],
)

pdf = client.invoice_pdfs.render_content(invoice.id, locale="en")
pdf.write_to_file(f"{invoice.code}.pdf")

The API key is required. Your application may read it from an environment variable or secret manager, but the SDK never reads process configuration on its own. The key selects the Test or Live account; the SDK has no separate environment switch.

The client owns a pooled requests.Session by default. Applications that need custom proxy, TLS, adapter or observability configuration can inject one:

import os

import requests

from fiscalrail import FiscalRail

session = requests.Session()
client = FiscalRail(os.environ["FISCALRAIL_API_KEY"], session=session)

Injected sessions remain owned by the caller and are not closed by the SDK.

Invoice issuance automatically uses an idempotency key. Durable workflows can provide and persist their own:

invoice = client.invoices.issue(
    idempotency_key="a49b50f6-1571-4e06-a243-e258bda98e40",
    customer="cus_...",
    lines=[
        {
            "description": "Consulting services",
            "unit_price": "2500.00",
            "taxes": [vat.general],
        }
    ],
)

Payment instructions

Create reusable payment instructions, optionally make them account defaults, and set an invoice due date without sending bank details on every issuance:

from datetime import date

instruction = client.payment_instructions.create(
    label="Main EUR account",
    type="bank_transfer",
    bank_transfer={
        "beneficiary": "Example supplier",
        "iban": "ES91 2100 0418 4502 0005 1332",
        "bic": "CAIXESBBXXX",
    },
)

client.accounts.update(
    "acct_...",
    default_payment_instructions=[instruction.id],
)

invoice = client.invoices.issue(
    payment_terms={"due_date": date(2026, 9, 30)},
    lines=[
        {
            "description": "Consulting services",
            "unit_price": "2500.00",
            "taxes": [vat.general],
        }
    ],
)

Pass payment_terms={"options": [instruction.id]} to override the account defaults for a specific invoice. Pass an empty options list to render no payment instructions.

Typed request values

Calls are type checked directly. Exported TypedDict definitions also make larger payloads reusable without introducing runtime parameter wrappers:

from fiscalrail.params import InvoiceIssueParams

params = InvoiceIssueParams(
    customer="cus_...",
    lines=[
        {
            "description": "Consulting services",
            "unit_price": Decimal("2500.00"),
            "taxes": [vat.general, irpf.professionals],
        }
    ],
)

invoice = client.invoices.issue(**params)

Responses are dependency-free frozen dataclasses. Dates, timestamps and monetary amounts are parsed into date, datetime and Decimal values. Unknown response fields are retained in response.extra_fields for forward compatibility and remain available through attribute access.

The response dataclasses, request TypedDicts, enums and operation registry are generated from FiscalRail's OpenAPI contract. The public client and resource methods remain hand-written so they can expose domain verbs, pooling, idempotency and retry behavior instead of generator-shaped HTTP calls.

Resources

• client.accounts
• client.api_keys
• client.customers
• client.event_destinations
• client.events
• client.invoice_series
• client.invoices
• client.invoice_pdfs
• client.payment_instructions
• client.tax_ids
• client.tax_regimes

Invoices use the domain verbs issue and amend; they are never updated. Account resources expose list, retrieve, and update operations. Customer and series and payment-instruction resources expose ordinary create, retrieve, update, list and delete operations.

Verify webhooks

Verify the exact request body before parsing or processing it:

from fiscalrail.webhooks import construct_event

event = construct_event(raw_body, signature_header, signing_secret)

construct_event checks the HMAC in constant time, applies a five-minute timestamp tolerance, and raises WebhookSignatureError when verification fails.

Development

uv sync --all-groups
uv run python scripts/generate_contract.py
uv run python scripts/generate_contract.py --check
uv run pytest
uv run ty check
uv run ruff check .
uv build

Release maintainers should follow the release guide.