ELSTER integration
as internal middleware
Let your team submit German tax declarations via a clean REST API — without maintaining ERiC, threading, or XML compliance yourself. Built for ERP, tax, and payroll software vendors.
We solved ERiC so you don't have to
ERiC is a low-level C client, single-threaded by design, with XML schemas that change every year. Elmar.tax packages the hard parts so your team can focus on product.
Three layers. Use what you need.
Most teams start with the REST layer. Java teams with deeper requirements can embed the lower layers directly.
Elmar REST
Deploy ELSTER as middleware inside your stack. Accepts JSON or XML payloads. Transfer tickets for tracking. Docker-first. Works from any language that speaks HTTP.
elster-databinding
Type-safe Java models generated from official ELSTER XSDs. Uniform factory pattern across form types and years. Makes version differences visible and manageable.
eric-wrapper-sdk
Modern Java wrapper around ERiC using Project Panama (Foreign Function & Memory API). No JNI. Concurrency-safe. Cross-platform (Linux + macOS).
Supported tax forms
Each form is exposed as a dedicated REST endpoint. New forms and years are added as modules.
UStVA
Umsatzsteuer-Voranmeldung (VAT advance return) — 2025, 2026
USt
Umsatzsteuer-Erklärung (annual VAT return) — 2025
GewSt
Gewerbesteuer-Erklärung (trade tax) — 2024
KSt
Körperschaftsteuer-Erklärung (corporate income tax) — 2024
FSE KapG
Feststellungserklärung KapG (determination of taxable income) — 2023
More coming
ESt, balance sheet forms, and new tax years are on the roadmap.
Built for software vendors, not end users
This is for you if…
You build ERP, tax, or payroll software and need reliable ELSTER integration inside your product. Your team wants a clear HTTP boundary instead of embedding a C library.
This is not for you if…
You're looking for a hosted SaaS portal, a user-facing tax filing app, or a turnkey cloud solution. Elmar.tax is infrastructure — it runs inside your stack, not ours.
Why not SaaS?
ERiC's licensing terms prohibit operating it as a SaaS or portal solution. Elmar.tax is designed around this constraint — turning it into a compliance advantage.
The regulatory reality
The ELSTER ERiC library explicitly prohibits SaaS/portal usage (Portallösung). Any hosted ELSTER service operates outside these terms or uses a different integration path.
Our approach
Elmar.tax runs inside your infrastructure. Your certificates stay with you, no data leaves your network (except to ELSTER), and you maintain full operational control.
Built because we had to ship it ourselves
Elmar.tax started from real integration work. It is already running in production, including with early adopter getmika. The project is maintained by practitioners who understand both ERiC and the realities of enterprise Java.