NONOX Connect API · v1.1.0

Build on Swedish bookkeeping that is open for real.

NONOX Connect is the API of NONOX: read the chart of accounts, create and post vouchers, attach documents and keep customers and suppliers in sync. Free, with no add-on fee, secured with OAuth 2.0 and passkeys, and documented down to every error code.

Get started in five minutes API reference openapi.yaml

Base URLhttps://nonox.app/api/v1

What the API covers

BookkeepingChart of accounts, VAT codes, fiscal years and voucher series: what a program needs to book correctly.

VouchersCreate drafts, post them with gapless numbers, correct posted vouchers and attach receipts and invoices.

RegistersCustomers and suppliers, with sync of everything that changed since last time.

StandardsOpenAPI 3.1, OAuth 2.0 with PKCE, RFC 9457 errors, idempotent writes and rate-limit headers.

Company The company the credential belongs to. 1 endpoints Bookkeeping Reference data for bookkeeping: chart of accounts, VAT codes, fiscal years and voucher series. 8 endpoints Vouchers Vouchers: drafts, posting, corrections and attachments (underlag). A posted voucher is immutable. 10 endpoints Customers The customer register. 4 endpoints Suppliers The supplier register. 4 endpoints Cost centres and projects Cost centres (SIE dimension 1) and projects (dimension 6). 8 endpoints Reports Trial balance, general ledger, balance sheet and income statement as JSON. 4 endpoints VAT VAT periods and the VAT return per period (read-only). 2 endpoints Articles The article register. 4 endpoints Customer invoices Customer invoices: drafts, issuing, e-mail, credit, payments and PDF. An issued invoice never changes. 9 endpoints Supplier invoices Supplier invoices: drafts, file, registering, approval with segregation of duties and payment. 9 endpoints Payments Incoming and outgoing payments, read-only. 2 endpoints

Free, with no add-on fee

Reaching your own figures from another program should not cost extra. This is how it works in NONOX.

No add-on feeThe API is a module in NONOX like every other. There is no price per call, per app or per integration.

Free when you run it yourselfNONOX is open source (AGPL-3.0). On your own server the API costs nothing, now or later.

Included when we run itThe hosted service includes every module, the API too. It is not a premium tier.

Your data, your way outAn open API is part of not being locked in, next to SIE4 and the archive package. Reading the code shows exactly what each call does.

Security, in plain words

Every token and key belongs to exactly one company. Another company's ids answer 404, so the API never reveals what exists.
An app gets in only when an owner or administrator approves it on a Swedish consent screen and confirms with a passkey.
Access tokens live at most 15 minutes. Refresh tokens change on every use, and one that comes back a second time revokes the whole connection.
A call may do what its scopes allow and what the person behind it may do in the company right now. A changed role counts on the next call.
API keys always expire, can be limited to IP addresses, are shown once and stored only as a SHA-256 fingerprint.
Every write, approval and revocation is in the company's audit trail. Personal numbers are never returned.
A posted voucher can never change. The API can post a draft or correct a voucher, just like the app.

The details: Authentication (OAuth), API keys, Scopes and the security page (Swedish).

Get started in five minutes

Turn on NONOX Connect

As owner or administrator of a company, open Inställningar → Moduler and turn on NONOX Connect. Use a company of your own for testing.
Create an API key

Under Anslutningar, create a key with the scopes vouchers:view, vouchers:create and vouchers:post and an expiry date. Confirm with your passkey and copy the key; it is shown once.
```
export NONOX_TOKEN="nnx_…"
```

Check which company the key belongs to

curl "https://nonox.app/api/v1/company" \
  -H "Authorization: Bearer $NONOX_TOKEN" \
  -H "Accept: application/json"

Create a voucher draft

Amounts are whole öre: 125000 is SEK 1,250.00. The Idempotency-Key makes a retry safe.

curl -X POST "https://nonox.app/api/v1/vouchers" \
  -H "Authorization: Bearer $NONOX_TOKEN" \
  -H "Accept: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
  "voucher_date": "2026-03-02",
  "description": "Kontantförsäljning",
  "series": "A",
  "rows": [
    {
      "account": 1930,
      "debit_ore": 125000
    },
    {
      "account": 3001,
      "credit_ore": 100000
    },
    {
      "account": 2611,
      "credit_ore": 25000
    }
  ]
}'

Post it

Use the id from the answer. The voucher gets the next number in its series, with no gaps, and can never change again, only be corrected.

curl -X POST "https://nonox.app/api/v1/vouchers/0b9f3c1e-6a2d-4f7b-9c8e-1d2a3b4c5d6e/post" \
  -H "Authorization: Bearer $NONOX_TOKEN" \
  -H "Accept: application/json" \
  -H "Idempotency-Key: $(uuidgen)"

The full getting-started guide, in PHP, JavaScript and Python too →

Guides

Getting startedFrom nothing to a posted voucher through the API in five minutes: module, key and the first calls. Authentication (OAuth)OAuth 2.0 authorization code with PKCE step by step, with real requests and responses, passkey consent and token rotation. API keysKeys for a company's own scripts and integrations: how they are created, what they may do and how they are revoked. ScopesEvery scope, which calls it opens and how it combines with the person's own role in the company. IdempotencyAn Idempotency-Key on every POST, so a retry after a network error never books anything twice. Pagination and syncCursor-paginated lists, and how a sync fetches only what changed with updated_since. ErrorsEvery error as problem+json (RFC 9457): the fields, every code and what a program should do. Rate limitsHow many calls per minute are allowed, the headers that show it and how to back off. WebhooksEvents sent to your server when something is booked, and how to verify the signature in PHP, JavaScript and Python. Self-hostingThe API on a NONOX you run yourself: addresses, signing keys, apps and limits.