# Quaderno (slim)

> Sales tax, VAT and GST software for online businesses from Recrea Systems, a Visma company in Spain. Its REST API calculates tax for a sale, records sales and refunds, issues invoices and credit notes and exports tax reports.

- Full: https://www.anchorterminal.com/tools/quaderno.md (~7,000 tokens) · this version ~1,730 tokens · JSON https://www.anchorterminal.com/tools/quaderno.json · canonical https://www.anchorterminal.com/tools/quaderno
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-08

**C · 59.5/100 · rank #377 of 629 · #3 in Tax calculation & compliance · not agent-ready · confidence medium**


Assessment: A public OpenAPI 3.1 spec covers 92 operations, with a free sandbox and a status page showing no incident since July 2025. The API key has full account access, there are no idempotency keys, and the newest public API version is dated October 2024.

## Facts

- Kind: HTTP API · vendor: Recrea Systems, SL · category: Tax calculation & compliance · legal entity: Recrea Systems, SL · provenance 83/100
- Endpoint: `https://quadernoapp.com/api` (HTTP)
- Auth: OAuth or key · pricing: Paid · x402: no · licence: Proprietary service under Quaderno's terms of service. The Ruby library on GitHub is MIT
- Probe metrics: not measured yet (probes haven't run)
- API: REST over HTTPS at https://ACCOUNT_NAME.quadernoapp.com/api, 92 operations in an OpenAPI 3.1 spec. Groups are transactions, contacts, products, tax rates, tax IDs, jurisdictions, tax codes, evidence, invoices, receipts, credit notes, proformas, expenses, recurring documents, checkout sessions, coupons, Connect accounts, reporting and webhooks
- Credentials: API key as the Basic auth username, with the account's full access. OAuth 2.0 authorisation code for Connect apps, scopes read_only and read_write, access tokens valid 25 days
- Rate limits: 100 API calls per 15 seconds, with X-RateLimit-Limit, X-RateLimit-Remaining and X-RateLimit-Reset headers and 429 on excess. Monthly API calls are capped at ten times the plan's transactions
- Pagination: 25 objects by default, `limit` up to 100, cursor by `created_before`, with X-Pages-HasMore and X-Pages-NextPage headers
- Sandbox: https://sandbox-quadernoapp.com, free, separate credentials, 200-document cap, POST /purge to clear it. Tax ID DE111111111 tests an invalid ID and IE222222222 an unavailable validator
- Trial: 7 days, no card
- Versioning: Versions named by date, 20160602 to 20241028, chosen in account settings or per request with `Accept: application/json; api_version: 20241028`. A preview of 20260309 is in the docs. Sunsetting with at least one month's notice
- Reports: POST /reporting/requests builds a tax_summary, invoices_list or credits_list file for a date range, ready some minutes later at `report_url`
- Tax ID validation: GET /tax_ids/validate returns true, false or null when the external service is down. Covers the EU, United Kingdom, Switzerland, Quebec, Australia and New Zealand
- Webhooks: HMAC-SHA1 signature in X-Quaderno-Signature, hourly retries for up to 72 hours, threshold.warning, threshold.exceeded and threshold.eu.100k events for registration alerts
- SDKs: Ruby gem quaderno 3.0.1 (29 July 2024, MIT) and PHP quaderno/quaderno v2.1.4 (4 July 2026)
- SLA: 99.99 per cent monthly uptime for Quaderno Premium customers, with credits of ten times the hourly rate for a day with an outage over 5 minutes
- Hosting: DigitalOcean in the Netherlands and AWS in Ireland, per the Visma Trust Centre
- Filing: Registration and return filing are a done-for-you service booked through a call, not API operations
- Prices: Hobby plan, 25 transactions $29 per month (plan); Startup plan, 250 transactions $49 per month (plan); Business plan, 1,000 transactions $99 per month (plan); Growth plan, 2,500 transactions $149 per month (plan)

- Scores: Reliability 91, Performance pending, Schema & documentation 77, Agent ergonomics 56, Security & auth 39, Payments & pricing 30, Task success pending, Maintenance & community 28, Transparency & trust 76 · total over the 7 assessed categories
- Why: Reliability, Graded on the public REST API. · Schema & documentation, OpenAPI 3.1 spec for version 20241028 at developers.quaderno.io/redocusaurus/openapi-v20241028.yaml, 92 operations (25). · Agent ergonomics, No MCP server from the vendor, so this is the REST API. · Security & auth, An API key sent as the Basic auth username. · Payments & pricing, No x402, MPP or L402 (0). · Maintenance & community, The newest public API version is 20241028. The PHP library's v2.1.4 came out on 4 July 2026, 96 days before the check, and the OpenAPI files… · Transparency & trust, Closed service under terms updated on 15 September 2026 that name Recrea Systems, SL and Spanish law.
- Sources: 23, open questions: 6, both in the full twin
- Capabilities: tax.calculate, tax.transactions, tax.invoicing
- JSON: https://www.anchorterminal.com/api/v1/tools/quaderno.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/quaderno.svg` or a link to https://www.anchorterminal.com/tools/quaderno from a page on quaderno.io or one of its subdomains, or the README of github.com/quaderno/quaderno-ruby, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.

## Before you call it

1. Call GET https://quadernoapp.com/api/authorization first. Its `href` gives the account subdomain that every other call needs
2. Before retrying a failed POST /transactions, list invoices by `processor_id` to check whether the sale was recorded. There is no idempotency key
3. Treat GET /invoices/{id}/deliver as a write. It emails the invoice to the customer
4. Correct a final invoice with a credit note. DELETE on invoices returns 410 and PUT accepts only notes, tags, metadata and address fields
5. Read X-RateLimit-Remaining and X-RateLimit-Reset, and page with `created_before` and `limit` up to 100

## Connect

```bash
gem install quaderno
```

```bash
curl "https://ACCOUNT_NAME.quadernoapp.com/api/tax_rates/calculate?to_country=US&to_postal_code=10128" \
  -u YOUR_API_KEY:x
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/quaderno

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| Avalara AvaTax | B | 68.8 | tax.calculate, tax.transactions, tax.invoicing | https://www.anchorterminal.com/tools/avalara.min.md |
| Vertex O Series | C | 54.7 | tax.calculate, tax.transactions, tax.invoicing | https://www.anchorterminal.com/tools/vertex-tax.min.md |
| Anrok | C | 61.6 | tax.calculate, tax.transactions | https://www.anchorterminal.com/tools/anrok.min.md |
| TaxJar | C | 57.6 | tax.calculate, tax.transactions | https://www.anchorterminal.com/tools/taxjar.min.md |


## Panel reviews (0, desk reviews from public material, no calls made)