specification: API Commons Rate Limits
specificationVersion: '0.1'
schema: https://raw.githubusercontent.com/api-evangelist/interface-research/main/schema/api-commons.yml#/$defs/RateLimits
provider: Quaderno
providerId: quaderno
created: '2026-07-03'
modified: '2026-07-03'
reconciled: false
tags:
- Tax Compliance
- Sales Tax
- VAT
- Invoicing
- Rate Limiting
- Quotas
description: >-
  Quaderno documents a fixed rate limit on its REST API: 100 requests per 15
  seconds per account. Exceeding the limit returns HTTP 429 (Too Many Requests).
  Quaderno notes it may tune the limit but keeps it high enough for a
  well-behaving interactive app. The rate limit is separate from a plan's
  monthly transaction allowance, which meters billed documents rather than API
  calls. The /ping endpoint can be used to check availability and remaining
  allowance without consuming rate limit.
notes: >-
  An older generation of the API documented a per-day request cap with
  X-RateLimit-Limit / X-RateLimit-Remaining headers; the current documented
  limit is 100 requests per 15 seconds returning 429 on excess. Verify current
  numbers and any per-endpoint nuances on https://developers.quaderno.io/api/
  during reconciliation. Tax calculation and validation calls count toward the
  same limit.
sources:
- https://developers.quaderno.io/api/
- https://developers.quaderno.io/
responseCodes:
  throttled: 429
limits:
- name: API Requests
  scope: account
  metric: requests
  limit: 100 per 15 seconds
  notes: Documented account-wide REST API rate limit; excess returns HTTP 429.
- name: Ping
  scope: account
  metric: requests
  limit: no rate-limit cost
  notes: The /ping endpoint checks availability and remaining allowance without consuming rate limit.
- name: Monthly Transactions
  scope: account
  metric: transactions
  limit: per plan
  notes: Not a request-rate limit - a billing allowance of processed documents per plan tier.
policies:
- name: Throttling Response
  description: Requests beyond 100 per 15 seconds receive HTTP 429 (Too Many Requests).
- name: Backoff Strategy
  description: Clients should implement exponential backoff with jitter and retry 429 responses after a short delay.
- name: Server Error Retry
  description: 5xx responses (500, 502, 503, 504) are transient and should be retried later by the client.
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com