Billy API
Billy API: A low-cost REST API for invoices, ledger data and accounting workflows in Billy. Ranked #22 of 28 in Accounting APIs by our editors (7.0/10); pricing: Free plan · 30-day trial; best for low-cost invoice and ledger API access.
At a glance
- Editor score7.0 / 10
- PricingFree plan · 30-day trial
- Best forLow-cost invoice and ledger API access
- Free planYes
- Paid from160 DKK/mo
- Sync directionTwo_way
- Facts checked20 Sep 2026
Where it wins
- Free plan with invoice, ledger, payment and contact access
- Supports invoice CRUD, filtering, sorting and pagination
- Access tokens and HTTP Basic Auth support integration flexibility
Where it doesn't
- Focused on Billy rather than a broad accounting ecosystem
- Unlimited integrations begin with the Plus plan
- Phone and priority accounting support are limited to higher tiers
Our verdict on Billy API
Billy API connects external software with Billy, an online accounting platform for Danish small businesses and self-employed users. Its JSON-based REST API covers invoices, contacts, products, product prices, daybook transactions, transaction lines, postings, payments, accounts and tax data. Developers can read, create, update and delete many resources, while paging, filtering, sorting and multiple localization options support data workflows. Authentication is available through access tokens or HTTP Basic Auth, and the service is offered across web and API environments.
Pricing follows Billy’s accounting plans. Free costs 0 DKK per month and includes the accounting system, invoicing, VAT reporting, email and chat support, and receipt upload. Basic costs 160 DKK per month and adds no usage limits, ad-free invoices, accounting support, and accountant access. Plus costs 295 DKK per month and adds advanced AI accounting features, Copilot access, unlimited integrations, and phone support. Complete costs 595 DKK per month and adds quarterly accounting review and priority accounting support. A 30-day free trial is also available, with monthly prices displayed in DKK excluding VAT.
The main fit is for teams that already work in Billy and need direct access to invoice and ledger resources through a conventional REST interface. The API’s coverage suits synchronization, transaction access, payment associations and localized accounting workflows. Its narrower Billy-centered scope makes it less suitable for organizations seeking a neutral accounting API across multiple platforms. Buyers should also distinguish the accounting subscription tiers from the API’s technical surface: higher plans add operational accounting benefits such as unlimited integrations, Copilot and priority support, while the core API value is its access to Billy data and workflows.
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Billy API pricing
All 4 Billy API plans and prices →
Billy API fact sheet
| Free plan | Yes |
|---|---|
| Paid from | 160 DKK/mo |
| Included connections | Not verified |
| Invoice sync | Yes |
| Journal entries | Yes |
| Sync direction | Two_way |
| Webhooks | Not verified |
| Sandbox environment | Not verified |
| API authentication | Both |
| Free trial | 30 days |
| Deployment | Cloud |
| Platforms | Web |
| Support | Email, Live chat, Phone, Docs |
| Built for | Solo, Small business, Mid-market (editorial estimate) |
| Integrations | 80+ integrations See all → |
| Pricing | Free plan · 30-day trial (source) |
| Website | billy.dk |
| Facts checked | 20 Sep 2026 |
Alternatives to Billy API
- RutterA broad accounting API for bidirectional sync across 15 listed platforms.9.4
- MergeA developer-focused accounting API with normalized models, two-way sync, and sandbox support.9.3
- ApideckA mature unified accounting API for teams connecting multiple finance systems.9.1
See all Billy API alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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