GoBD-compliant invoicing + DATEV export + Elster integration with **English UI as primary**, German UI as secondary. Plus partial-payment tracking (which Accountable.de lacks). Built specifically for the expat freelancer profile, not a translated afterthought of a German product.

What we ship

**Core features (MVP)**

• English-first invoicing (with German legal text auto-injected per GoBD rules) — issue PDF + ZUGFeRD/XRechnung-compliant invoices in EN.
• Partial-payment tracking with EUR/USD/GBP support — log €1,200 invoice paid as €700 today + €500 next month, automatic reminder schedule.
• DATEV-compatible export (CSV + DTVF format) — hand off to your Steuerberater in one click, no formatting fights.
• Elster integration for quarterly Umsatzsteuer-Voranmeldung — pre-filled, one-click submission via the German tax-office API.
• Receipt OCR (Claude-powered): photo a receipt, get auto-categorized expense + GoBD-archived PDF in R2.

**Primary user flow**

1. Berlin-based developer searches "GoBD English freelance tool" or sees us in r/selbststaendig — lands on EN landing.

2. Sign up with email, pick country (DE/AT/CH), connect bank via SEPA / Open Banking — onboarding is 4 minutes, all in English.

3. Issues first invoice to a US client in USD, marks partial payment, exports DATEV file at month-end → sends to Steuerberater. Saves €100+ vs paying Steuerberater for the same task.

4. After 14-day free trial, €19/mo Solo via Stripe SEPA. Pro upgrade trigger: when they need ZUGFeRD for a B2B-government client.

**What it looks like**

• **Landing page**: bilingual hero — large EN headline "German tax compliance. In English. Finally." + small DE subtitle "GoBD-konform, DATEV-Export, Elster — auf Englisch." Hero visual: invoice screenshot with EN labels + a DATEV export button. Trust badges: "GoBD certified", "Elster verified", testimonials from Berlin/Munich expats. CTA: "Start 14-day free trial — no German required."
• **Main app screen**: invoice editor. Left column: client picker (with multi-currency), line items in EN with auto-translated DE legal footer toggleable. Right column: live PDF preview showing both EN and the legally-required German fields. Bottom action bar: Save / Send / Mark as paid / Record partial payment. Top nav: Dashboard | Invoices | Expenses | Reports | DATEV Export | Elster.
• **Notification / output format**: invoice PDFs with EN labels but German VAT-line, Steuernummer, and Kleinunternehmerregelung disclaimer in DE; DATEV export = .csv that drops directly into the Steuerberater's tooling; Elster confirmation = green banner + downloadable Bescheid PDF.

**MVP build plan (21 days)**

• Day 1-3: FastAPI + Postgres + Stripe SEPA on Railway, EUR-primary billing, multi-tenant auth.
• Day 4-7: invoice CRUD, multi-currency, partial payments, EN+DE legal-text engine, GoBD audit log (immutable).
• Day 8-11: ZUGFeRD/XRechnung XML-embed in PDF, ZUGFeRD validator, e-invoice send via email.
• Day 12-14: DATEV export (CSV + DTVF), expense module, R2 receipt storage, Claude OCR for receipts.
• Day 15-17: Elster API integration (Umsatzsteuer-Voranmeldung), test with sandbox certificates.
• Day 18-19: react-i18next setup (EN default, DE fallback), Cloudflare Pages landing, pricing.
• Day 20: Reddit launch posts, Berlin co-working partnership outreach, content draft for "GoBD compliance for English speakers".
• Day 21: end-to-end test (issue invoice → mark paid → export DATEV → submit Elster), ship.

Source signals

• `SIG-20260426-dach-micro-saas-utility-english-ui-de-accounting` — Reddit r/selbststaendig thread with B1-level expat asking about GoBD-compliant + EN UI tool; 4+ commenters confirmed same pain. Existing options are German-only or feature-gapped.

Reasoning

This is a regulatory moat product. GoBD compliance + DATEV export + ZUGFeRD/XRechnung + Elster API integration are non-trivial to implement. German native tools (Lexoffice, sevDesk) have it but English UX is afterthought. International tools (FreeAgent, FreshBooks) don't bother with German tax compliance.

The expat freelancer market is concentrated:

• Berlin: 24K English-speaking freelancers
• Munich: 12K (BMG estimate)
• Vienna: 8K
• Hamburg: 6K
• Zurich: 15K (Swiss freelancers + SwissDe)

Price elasticity: vs Steuerberater (€100-300/mo) at €19-29/mo we're a no-brainer for expats who don't yet have an annual €5K+ Steuerberater relationship.

Quick competitive read

• **Accountable.de** (~€10/mo) — closest competitor, English UI, but lacks partial payments + B2B invoicing edge cases per Reddit thread. Founded 2018.
• **Sorted** (~€8/mo) — international solo-freelancer tool with EN UI, DE+other markets. Less DE-specific (no DATEV depth).
• **Lexoffice** (€5.90/mo from), **sevDesk** (€10/mo) — German-only, won't pivot.
• **Qonto** (banking + invoicing) — French, sells in DE; invoicing is bolt-on.

Density: 2 direct competitors with feature gaps. Medium-low pressure. White-space: depth in expat-specific edge cases (partial payments, foreign-client EUR/USD handling, exit-from-DE workflows).

Initial pricing hypothesis

€19/mo Solo (single user, GoBD + DATEV export + Elster), €29/mo Pro (+ ZUGFeRD/XRechnung + multi-bank + Steuerberater portal access). Annual 20% off. 14-day free trial.

Distribution hypothesis

1. **Reddit r/selbststaendig + r/germany + r/Berlin** — answer expat-pain threads helpfully (build-in-public approach).

2. **Expat-focused content** — "GoBD compliance for English-speaking freelancers" SEO content.

3. **Co-working partnerships** — Mindspace, WeWork, Factory Berlin have ~80% expat freelancer mix.

4. **Steuerberater partnerships** — they hate doing low-margin freelancer work; we offload it; they get the upmarket cases.

5. **Diaspora communities** — r/IWantOut, /r/germany, expat Slack groups.