Open source from v0.1 · built in Switzerland

The billing framework for Swiss software

Subscriptions, invoices, shop and members – as a library that runs inside your app. QR-bill, TWINT, VAT and four languages are built in, and the data stays in your database. From club projects to SaaS, in TypeScript and PHP.

Get started See the roadmap

npx agentkit init

Invoice

subkit

Reference	Payable by	payment provider	Amount CHF
2026-0142	FC Seebach	TWINT	228.00
2026-0141	Chor Bern-Nord	QR-bill	1'240.00
2026-0140	Turnverein Wil	Mastercard	96.50
2026-0139	Club alpin Sion	QR-bill	1'900.00
2026-0138	Società ginnastica Lugano	Visa	340.00

Pick what your product needs.

Each kit works on its own, and they all share one adapter, one customer and one payment provider. Same kit, same behaviour, in every programming language we ship.

subkit

Preview

Subscriptions & invoices

Plans, trials, proration
Card, TWINT or QR-bill
Reminders & retries
VAT on every invoice
Entitlements & limits
Billing portal UI

npm i @agentkit/subkit

membershipkit

In progress

Members & renewals

Membership types & seasons
Households & families
Renewal campaigns
Signup forms & custom fields
Fee invoices via subkit
Member cards & export

npm i @agentkit/membershipkit

shopkit

planned

Commerce

Products & variants
Cart & checkout with TWINT
Orders & refunds
Stock & Swiss Post shipping
Discount codes
Gift vouchers

npm i @agentkit/shopkit

eventkit

Events, registrations, tickets, waitlists

bookingkit

Appointments, resources, reservations

invoicekit

One-off invoices with QR-bill, no subscription

mailkit

Newsletters, lists, double opt-in

Swiss by default

Not localised later. Swiss from the first line

Generic billing libraries think in Stripe, cents and one language. Swiss customers pay by QR-bill and TWINT, expect VAT on every invoice and read it in German, French or Italian. agentkit starts there.

Rechnung deFacture frFattura itInvoice en

Receipt

Account / Payable to

CH44 3199 9123 0008 8901 2
Acme AG
Bahnhofstrasse 1
8001 Zürich

Reference

21 00000 00003 13947 14300 09017

Payable by

FC Seebach
Dorfstrasse 12
8052 Zürich

Currency

CHF

Amount

228.00

Payment part

Currency

CHF

Amount

228.00

Account / Payable to

CH44 3199 9123 0008 8901 2
Acme AG
Bahnhofstrasse 1
8001 Zürich

Reference

21 00000 00003 13947 14300 09017

Additional information

Invoice 2026-0142 · Club Pro, annual plan
incl. 8.1 % VAT CHF 17.08 · CHE-123.456.789 VAT

Payable by

FC Seebach
Dorfstrasse 12
8052 Zürich

Generated by subkit: QR-IBAN with QR reference, VAT line, payer from your customer table. Sample data.

Swiss QR-bill

live

Payment part per SIX guidelines, QR-IBAN with QR reference or IBAN with RF creditor reference. CHF and EUR. Scan-to-pay in every Swiss banking app.

TWINT via zahls.ch

live

Payments through zahls.ch with TWINT and credit cards. Card data never touches your server. Other providers plug in through one interface.

VAT done right

live

Inclusive or exclusive prices, VAT line and CHE number on every invoice, integer Rappen instead of floats. Per-line rates (8.1 / 2.6 / 3.8 %) and 5-Rappen rounding are next.

de · fr · it · en

live

UI, emails and invoices in German, French, Italian and English, with Swiss formats: 15.10.2026, CHF 1’900.00, «guillemets», ss instead of ß.

Bank reconciliation

Import camt.054 / camt.053 from your bank, match QR references to open invoices and mark them paid. No more manual matching of bank statements.

Reminders, Swiss style

Today: payment terms, automatic retries and reminder emails. Next: 1st, 2nd and 3rd reminder with fees, reminder PDFs with a fresh QR-bill, export for debt collection.

revDSG friendly

by design

The kits run in your app and write to your database. No extra processor for your customer data – host it in a Swiss data centre if you like.

eBill

planned

Deliver invoices straight into the e-banking of your customers through the Swiss eBill network, with the QR-bill as fallback.

A library in your app. Not a service in front of it.

Your app

Next.js · Laravel · Symfony · Hono
<BillingPortal /> · <ak-cart>
your auth → authorize()

agentkit · in your process · TS or PHP

subkit · membershipkit · shopkit
core · schema · events · i18n
database adapter · payment provider

Yours

Your Postgres · MySQL · SQLite
zahls.ch · TWINT
Your bank · camt.054
Your mailer

One spec. Native in every stack.

Every kit is defined once – schema, rules, HTTP API, emails, translations – and implemented natively per programming language. A shared conformance suite runs the same billing scenarios against each implementation, so a renewal in PHP produces exactly the rows a renewal in TypeScript does. The React UI talks to both.

TypeScript

Next.js · Hono · SvelteKit · Nuxt · Express · Workers

Drizzle · Prisma · Kysely

reference

PHP

Laravel · Symfony · PHP 8.3+

Eloquent · Doctrine · PDO

Python

Django · FastAPI · Flask

Django ORM · SQLAlchemy

later

Everything around the money, done once.

Your database

The data never leaves your app.

Kits write to tables in your database through adapters. Join them, back them up, migrate away – no sync, no silo.

DrizzlePrismaEloquentDoctrinePDO

Any stack

TypeScript and PHP, one HTTP API.

Native libraries per language, mounted as a route in your framework. Every implementation speaks the same API, so the same UI works on top.

Next.jsHonoLaravelSymfonyOpenAPI

Host it anywhere

Your servers, your data centre.

Vercel, a Swiss cloud or the server in the basement: the kits go wherever your app goes. There is no agentkit backend to call home to.

InfomaniakExoscaleSwisscomVercelon-prem

UI included

Self-service out of the box.

Drop-in components for the boring screens – React, or a web component for Blade and Twig. Headless hooks when you want your own.

<BillingPortal />useBilling()<ak-cart>

Emails & documents

Every lifecycle email, ready.

Receipts, failed payments, reminders, renewals, order confirmations – in four languages, HTML and text, any mailer. Printable invoices with QR-bill.

ResendSMTPPostmarkPDF

Agent-native

Your coding agent can wire it in.

llms.txt, skills, an MCP server per kit and errors that link to the fix. One prompt from zero to a working checkout.

llms.txtMCPSkillsAGENTS.md

Correct by design

Money paths are boring on purpose.

Compare-and-set updates, idempotent webhooks, transactions where it matters. One conformance suite for every language and database.

CASIdempotencyTransactions

Composable

Kits that know each other.

One customer, one payment provider, one invoice system across kits. Membership fees and shop orders end up on the same QR-bill.

Shared customerTyped eventsPlugins

Open source

MIT. Every line readable – from v0.1.

The code goes public on GitHub with version 0.1. No per-transaction fee to us, no lock-in. A hosted dashboard and webhook relay will be optional, not required.

MITTypeScriptPHPTested

Declared in code. Reviewed in pull requests.

Kits describe their tables declaratively. The CLI turns that into a schema or migration for the ORM you already use – Drizzle, Prisma, Eloquent, Doctrine – and every adapter passes the same conformance suite.

import { agentkit } from '@agentkit/core';
import { drizzleAdapter } from '@agentkit/drizzle';
import { subkit } from '@agentkit/subkit';
import { shopkit } from '@agentkit/shopkit';
import { membershipkit } from '@agentkit/membershipkit';
import { zahls } from '@agentkit/zahls';

export const kit = agentkit({
  database: drizzleAdapter(db, { tablePrefix: 'ak_' }),
  payments: zahls({ instance: 'acme', apiKey: env.ZAHLS_KEY }),
  kits: [
    subkit({ plans, defaultPlanId: 'free' }),
    shopkit({ currency: 'CHF', vat: { rateBps: 810 } }),
    membershipkit({ seasons: 'yearly', invoiceWith: 'subkit' }),
  ],
});

kit.on('shop.order.paid', async ({ order }) => fulfil(order));

Extracted from production, one kit at a time.

Every kit comes from code that already runs in production and is pulled out once it has proven itself.

Q4 2026 · now
core + subkit
Adapter contract and test suite, Drizzle adapter, subkit 0.1 with QR-bill, VAT and zahls.ch/TWINT on npm. Docs in German and English.
Q1 2027
subkit for PHP
Conformance suite as language-neutral fixtures, PHP port with Eloquent, Doctrine and PDO adapters, Laravel and Symfony integration.
Q1 2027
membershipkit
Fee invoices through subkit. camt.054 bank reconciliation.
2027
shopkit & more
Catalogue, cart, TWINT checkout, Swiss Post shipping, vouchers. eBill, then eventkit and bookingkit.

Roll your own billing – in minutes, not months

Ship the product. Let the kits handle subscriptions, orders and members – Swiss-ready, in your database, under your control.

See the roadmap Designs

The billing framework for Swiss software

Pick what your product needs.

subkit

membershipkit

shopkit

Not localised later. Swiss from the first line

Swiss QR-bill

TWINT via zahls.ch

VAT done right

de · fr · it · en

Bank reconciliation

Reminders, Swiss style

revDSG friendly

eBill

A library in your app. Not a service in front of it.

One spec. Native in every stack.

Everything around the money, done once.

The data never leaves your app.

TypeScript and PHP, one HTTP API.

Your servers, your data centre.

Self-service out of the box.

Every lifecycle email, ready.

Your coding agent can wire it in.

Money paths are boring on purpose.

Kits that know each other.

MIT. Every line readable – from v0.1.

Declared in code. Reviewed in pull requests.

Extracted from production, one kit at a time.

core + subkit

subkit for PHP

membershipkit

shopkit & more

Roll your own billing – in minutes, not months