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Rechnungskit
Rechnungskit vs. FastBill

FastBill alternative for freelancers and small service businesses

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Rechnungskit creates invoices automatically from shop and payment events, locked from creation, with the date of supply from shipping and payment provider fees as finished DATEV bookings. FastBill is a well-rounded invoicing and preparatory bookkeeping tool for service businesses; in a shop setup, the invoice there usually only comes about through third-party tools.

Sources checked: July 28, 2026 · Updated: October 3, 2026 · No guarantee of accuracy · Sources below the table

The short version

Rechnungskit fits if …

your documents should come automatically from Shopify, Stripe, Mollie or your own software, without third-party apps, with GoBD locking from creation, OSS logic and fee bookings.

FastBill fits if …

you are a service provider or solopreneur who wants quotes, time tracking, banking and VAT return filing in one tool and writes invoices by hand or as recurring invoices.

FastBill is preparatory bookkeeping for service businesses, Rechnungskit is invoicing automation for sales channels: documents come from order, payment and shipping events and land with your tax advisor as finished bookings.

Rechnungskit and FastBill in detail

Every row is backed by a source. Where something couldn't be confirmed from public sources, the table says so.

Feature comparison of Rechnungskit and FastBill, as of July 28, 2026
Feature RechnungskitFastBill
E-invoicing
ZUGFeRD 2.x / Factur-X outgoing Yes ZUGFeRD 2.5 under EN 16931, every invoice Status: included Yes2 ZUGFeRD 2.3 in all plans; if mandatory fields are missing, a regular PDF is created, and the pre-check warns about it first Status: included, see footnote 2
XRechnung for public-sector buyers Yes XRechnung 3.0 automatically as soon as the customer has a Leitweg-ID (public-sector routing ID) on file Status: included Yes2 XRechnung 3.0; Leitweg-ID as a required field for all customers Status: included, see footnote 2
Validation before sending Mandatory fields under §14 UStG, tax rates, format rules Yes every invoice before sending (Mustang/EN 16931) Status: included Pre-check2 mandatory-field check; full EN 16931 validation not documented Status: limited, see footnote 2
Receive and process e-invoices No deliberately out of scope. Rechnungskit creates outgoing invoices Status: not available Yes2 ZUGFeRD is read automatically; XRechnung document data still manual according to the help center Status: included, see footnote 2
Shop automation
Native shop and payment integrations no third-party tools Yes Shopify, WooCommerce and Shopware natively, Stripe/Mollie/PayPal/Unzer, own checkout link for one-time purchases and subscriptions without a shop, own push API Status: included Via third-party tools3 Shopify via a third-party app (USD 14.99), Amazon/eBay via Billbee, WooCommerce plugin; Stripe only as a payment button, Mollie not available Status: limited, see footnote 3
Invoicing on the correct date of supply shipping date instead of payment date, automatically Yes from the shop's shipping event; for subscriptions, the service period comes from the billing period Status: included Manual3 preset "service period equals the invoice date"; no shipping event Status: limited, see footnote 3
Automatic cancellation invoices on refunds including partial refunds Yes to the cent, with its own correction document Status: included Manual3 cancellation invoice with one click; automatic only for Shopify cancellations via the third-party app Status: limited, see footnote 3
Payout reconciliation with fees Stripe, Mollie, PayPal and others as finished bookings Yes fees and payouts as bookings Status: included Not documented3 bank matching available; splitting payment provider payouts into revenue and fees not documented Status: no reliable source found, see footnote 3
Tax compliance
OSS / EU distance selling Yes destination-country rates, monitoring of the €10,000 threshold, export Status: included Basic2 EU destination-country tax rate configurable; no OSS filing and no monitoring of the €10,000 threshold documented Status: limited, see footnote 2
EU tax rates updated automatically Yes monthly from the EU database TEDB, with change alerts Status: included Not documented Status: no reliable source found
Qualified VAT ID (USt-IdNr.) check with evidence archive Yes qualified check with the BZSt (Federal Central Tax Office), response archived for 8 years Status: included Not documented no BZSt or VIES check found in the official documentation Status: no reliable source found
Single- and multi-purpose vouchers (§3 (13) to (15) UStG) Yes own voucher and store-credit register Status: included Not documented no voucher tax logic found in the documentation Status: no reliable source found
Deferred revenue (pRAP) / revenue recognition for subscriptions Yes pRAP for subscriptions and annual licenses Status: included Not documented no deferral feature publicly documented Status: no reliable source found
DATEV & archive
Finished DATEV booking records not just document images Yes EXTF for SKR03/SKR04, revenue + payments + fees; document images via Beleglink in the "Belegtransfer" package for Unternehmen online Status: included Yes4 DATEV format export without document images; invoice data service 1.0 with document images only from Pro Status: included, see footnote 4
GoBD archive with locking (Festschreibung) Yes WORM archive, SHA-256, locked from creation Status: included Manual4 locking is a separate step; invoices that are not locked can be set back to draft Status: limited, see footnote 4
Free access for your tax advisor Yes own tax advisor portal, documents read-only Status: included Yes1 from the Solo plan according to the pricing page; limited access (monthly report) Status: included, see footnote 1
Accounting & operations
VAT return (UStVA) / cash-basis accounts (EÜR) / direct ELSTER filing EC Sales List (ZM) import files are covered separately ZM data ZM import file yes; UStVA, EÜR and direct ELSTER filing stay with your tax advisor Status: limited Yes, a strength5 UStVA straight to the tax office, without your own ELSTER certificate, in all plans Status: included, see footnote 5
Entry price from €9 base fee + tiered price per document; free to test in sandbox mode Status: included from €91 Solo billed annually, no document limit stated; recurring invoices only from Pro (€27) Status: included, see footnote 1
API for your own systems Yes push API in every plan Status: included Yes6 public API from Solo; 50 to 1,000 calls per hour depending on the plan Status: included, see footnote 6

E-invoicing

ZUGFeRD 2.x / Factur-X outgoing
Rechnungskit Yes ZUGFeRD 2.5 under EN 16931, every invoice Status: included
FastBill Yes2 ZUGFeRD 2.3 in all plans; if mandatory fields are missing, a regular PDF is created, and the pre-check warns about it first Status: included, see footnote 2
XRechnung for public-sector buyers
Rechnungskit Yes XRechnung 3.0 automatically as soon as the customer has a Leitweg-ID (public-sector routing ID) on file Status: included
FastBill Yes2 XRechnung 3.0; Leitweg-ID as a required field for all customers Status: included, see footnote 2
Validation before sending
Mandatory fields under §14 UStG, tax rates, format rules
Rechnungskit Yes every invoice before sending (Mustang/EN 16931) Status: included
FastBill Pre-check2 mandatory-field check; full EN 16931 validation not documented Status: limited, see footnote 2
Receive and process e-invoices
Rechnungskit No deliberately out of scope. Rechnungskit creates outgoing invoices Status: not available
FastBill Yes2 ZUGFeRD is read automatically; XRechnung document data still manual according to the help center Status: included, see footnote 2

Shop automation

Native shop and payment integrations
no third-party tools
Rechnungskit Yes Shopify, WooCommerce and Shopware natively, Stripe/Mollie/PayPal/Unzer, own checkout link for one-time purchases and subscriptions without a shop, own push API Status: included
FastBill Via third-party tools3 Shopify via a third-party app (USD 14.99), Amazon/eBay via Billbee, WooCommerce plugin; Stripe only as a payment button, Mollie not available Status: limited, see footnote 3
Invoicing on the correct date of supply
shipping date instead of payment date, automatically
Rechnungskit Yes from the shop's shipping event; for subscriptions, the service period comes from the billing period Status: included
FastBill Manual3 preset "service period equals the invoice date"; no shipping event Status: limited, see footnote 3
Automatic cancellation invoices on refunds
including partial refunds
Rechnungskit Yes to the cent, with its own correction document Status: included
FastBill Manual3 cancellation invoice with one click; automatic only for Shopify cancellations via the third-party app Status: limited, see footnote 3
Payout reconciliation with fees
Stripe, Mollie, PayPal and others as finished bookings
Rechnungskit Yes fees and payouts as bookings Status: included
FastBill Not documented3 bank matching available; splitting payment provider payouts into revenue and fees not documented Status: no reliable source found, see footnote 3

Tax compliance

OSS / EU distance selling
Rechnungskit Yes destination-country rates, monitoring of the €10,000 threshold, export Status: included
FastBill Basic2 EU destination-country tax rate configurable; no OSS filing and no monitoring of the €10,000 threshold documented Status: limited, see footnote 2
EU tax rates updated automatically
Rechnungskit Yes monthly from the EU database TEDB, with change alerts Status: included
FastBill Not documented Status: no reliable source found
Qualified VAT ID (USt-IdNr.) check with evidence archive
Rechnungskit Yes qualified check with the BZSt (Federal Central Tax Office), response archived for 8 years Status: included
FastBill Not documented no BZSt or VIES check found in the official documentation Status: no reliable source found
Single- and multi-purpose vouchers (§3 (13) to (15) UStG)
Rechnungskit Yes own voucher and store-credit register Status: included
FastBill Not documented no voucher tax logic found in the documentation Status: no reliable source found
Deferred revenue (pRAP) / revenue recognition for subscriptions
Rechnungskit Yes pRAP for subscriptions and annual licenses Status: included
FastBill Not documented no deferral feature publicly documented Status: no reliable source found

DATEV & archive

Finished DATEV booking records
not just document images
Rechnungskit Yes EXTF for SKR03/SKR04, revenue + payments + fees; document images via Beleglink in the "Belegtransfer" package for Unternehmen online Status: included
FastBill Yes4 DATEV format export without document images; invoice data service 1.0 with document images only from Pro Status: included, see footnote 4
GoBD archive with locking (Festschreibung)
Rechnungskit Yes WORM archive, SHA-256, locked from creation Status: included
FastBill Manual4 locking is a separate step; invoices that are not locked can be set back to draft Status: limited, see footnote 4
Free access for your tax advisor
Rechnungskit Yes own tax advisor portal, documents read-only Status: included
FastBill Yes1 from the Solo plan according to the pricing page; limited access (monthly report) Status: included, see footnote 1

Accounting & operations

VAT return (UStVA) / cash-basis accounts (EÜR) / direct ELSTER filing
EC Sales List (ZM) import files are covered separately
Rechnungskit ZM data ZM import file yes; UStVA, EÜR and direct ELSTER filing stay with your tax advisor Status: limited
FastBill Yes, a strength5 UStVA straight to the tax office, without your own ELSTER certificate, in all plans Status: included, see footnote 5
Entry price
Rechnungskit from €9 base fee + tiered price per document; free to test in sandbox mode Status: included
FastBill from €91 Solo billed annually, no document limit stated; recurring invoices only from Pro (€27) Status: included, see footnote 1
API for your own systems
Rechnungskit Yes push API in every plan Status: included
FastBill Yes6 public API from Solo; 50 to 1,000 calls per hour depending on the plan Status: included, see footnote 6
Sources & footnotes
  1. 1. fastbill.com (pricing, banking), retrieved July 2026; prices net, billed annually.
  2. 2. support.fastbill.com: e-invoice setup (ZUGFeRD 2.3, XRechnung 3.0, pre-check), receiving and reading e-invoices, OSS procedure, VAT ID on the invoice, retrieved July 2026.
  3. 3. support.fastbill.com: Shopify interface (third-party app), Billbee connection, creating a cancellation invoice, invoice form (service period), banking, retrieved July 2026.
  4. 4. support.fastbill.com: DATEV export in DATEV format ("nur Buchungsdaten, keine Belegbilder", i.e. booking data only, no document images), DATEV invoice data service 1.0, locking invoices, editing invoices/setting them back to draft, retrieved July 2026.
  5. 5. fastbill.com/umsatzsteuervoranmeldung, retrieved July 2026.
  6. 6. apidocs.fastbill.com, retrieved July 2026.
  7. Information from the provider's website (pricing, feature and help pages), last checked on July 28, 2026; prices net of VAT.
  8. Rows marked "Not documented" mean we found no reliable public source, not that the feature is missing.
  9. Rechnungskit information reflects the current product; items marked "Planned" are not available yet.
  10. Legal basis for the rows and sections (German law): mandatory invoice details § 14 (4) UStG, e-invoicing § 14 (1) and (2) UStG with the transition rules in § 27 (38) UStG, small-amount invoices § 33 UStDV, vouchers § 3 (13) to (15) UStG, OSS threshold § 3c (4) UStG and filing § 18j UStG, VAT ID confirmation § 18e UStG, intra-EU supply § 6a UStG, tax arising in the filing period of the supply § 13 (1) no. 1 (a) UStG, retention § 14b (1) UStG and § 147 (3) AO, deferred revenue § 250 (2) HGB, archive GoBD, BMF letter of 28.11.2019.

All information from publicly available sources, checked July 28, 2026. Providers' features and prices can change. Please report mistakes to support@rechnungskit.de. How we rate is explained in How we compare.

When is FastBill the better choice?

Rechnungskit doesn't do everything. In these cases, FastBill is the more honest recommendation.

You want to file the VAT return from the tool

FastBill sends the VAT return (UStVA) straight to the tax office, without your own ELSTER certificate. Rechnungskit deliberately leaves filings to your tax advisor.

The full document cycle for service businesses

Quotes, order confirmations, delivery notes, time tracking and project billing: that's what FastBill is built for, not Rechnungskit.

Preparatory bookkeeping with banking and receipts

Multibanking with more than 4,000 banks, a receipt scanning app and dunning cover the complete preparatory bookkeeping.

Flat price with no stated document limit

The public pricing page shows no per-document metering. For lots of manual invoices that can be attractive.

What Rechnungskit does differently

Invoicing

Invoicing on the correct date of supply

Shipped goods are invoiced on the shipping date, not the payment date. It sounds like a detail, but it decides which period the revenue lands in.

Date of supply (Leistungsdatum) from the shop's shipping event
Small-amount invoices automatically under §33 UStDV
Handover to DATEV in the right period
Tax compliance

VAT ID check with evidence archive

Qualified check with the BZSt (Federal Central Tax Office) including company name, city, postcode and street. The response is archived unchanged for eight years and linked to the individual invoice.

Qualified BZSt check instead of a simple format check
Response linked to the invoice and delivery date
No tax-exempt invoice without a usable check
Accounting

DATEV bookings with linked documents

Your tax advisor gets finished EXTF booking records, not just a folder of PDFs. Revenue, payments, fees and payouts are already matched, and every invoice booking carries a Beleglink to its document image in the "Belegtransfer" package for Unternehmen online.

EXTF bookings for SKR03 and SKR04
Document image attached to the booking via Beleglink
Fees and payouts already matched
Your tax advisor downloads them directly

Price comparison

List prices net per month, as of July 28, 2026. Discounts and promotions are not included.

Rechnungskit List price
from €9 / month net + tiered price per document
Free to test in sandbox mode; billing starts at go-live
After that, a €9 base fee plus €0.15 to €0.03 per document
OSS, ZM, DATEV, GoBD archive and every feature always included
Self-service signup with no waiting list, up and running in minutes
Cancel monthly, no setup fee
FastBill List price
from €9 / month net, billed annually
Solo €9, Plus €14, Pro €27, Premium from €53
No document limit stated; recurring invoices only from Pro
Shopify third-party app by Make It Easy!: USD 14.99/month
Source: fastbill.com/preise, as of July 2026
Worked example
Shop with 500 orders a month: FastBill would need Billbee in front of it or the Shopify third-party app; the date of supply and payment provider fees remain manual work.
Rechnungskit
€68.00
FastBill
from €9 plus third-party tools

Switching in three steps

1
Bring your data over

Orders and payments from your connected sources are pulled in, and your invoice number sequence continues. Old documents stay available in your previous system; Rechnungskit doesn't import invoices created elsewhere.

2
Test in parallel

Both systems run side by side for one billing period. You compare documents and bookings before anything goes live.

3
Switch over

Sending is switched over and your tax advisor gets the new export access. The old system stays in place as an archive.

FAQ

No. Rechnungskit creates legally compliant invoices from your transactions and hands finished bookings to DATEV. Full accounting with cash-basis accounts (EÜR) and VAT returns (UStVA) stays with your accounting tool or your tax advisor.

Yes, and that's the usual way to switch. You run both systems in parallel for one billing period and compare documents and bookings before you switch over.

They stay where they are. Rechnungskit doesn't import or archive invoices created elsewhere; you keep meeting your retention duty for old documents (eight years under § 14b (1) UStG and § 147 (3) AO) in your previous system. What Rechnungskit can pull in are past orders and payments from your connected shops and payment providers, which then become new, validated invoices. For the number sequence, you set the number Rechnungskit continues from, so nothing overlaps with your old documents.

Documents are stored tamper-proof and unchangeable for eight years for as long as your account exists (WORM archive with checksums). Eight years is the retention period for invoices and accounting records (§ 14b (1) UStG, § 147 (3) AO); the requirements for the archive are set out in the GoBD. You can export them at any time, and for 90 days free of charge after you cancel. The final assessment of your process documentation (Verfahrensdokumentation) is up to your tax advisor.

FreshBooks acquired FastBill in 2021, and in 2024 founder René Maudrich and co-CEO Benjamin Kirschner bought it back in a management buyout. Since then it has been an independent German GmbH again, based in Frankfurt. This comparison was checked on July 28, 2026.

At FastBill, according to the support help, not in the DATEV format export ("nur Buchungsdaten, keine Belegbilder", booking data only, no document images); document images go along via the DATEV invoice data service 1.0, which is only available from Pro. Rechnungskit adds a "Belegtransfer" package for DATEV Unternehmen online to every revenue export, and every invoice booking carries the matching Beleglink; that is included in every plan.

From the providers' publicly available sources, checked on July 28, 2026, with footnotes for each row. Where we found no reliable source, the table says "Not documented". If you spot a mistake, write to support@rechnungskit.de and we'll correct it and re-date the page.

More comparisons

Rechnungskit is not a tax advisory or law firm. This article explains general principles and does not replace advice from a tax advisor (Steuerberater, § 5 StBerG) or a lawyer (§ 3 RDG). Rechnungskit is built for businesses based in Germany and prepares documents, tax rates and bookings automatically. How your specific case is treated remains your decision, ideally together with your tax advisor or a lawyer.

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