Data product · API — Design collaboration with DSL4 Digital, 2026
FestivosAPI
Every Spanish public holiday — national, all 17 comunidades, down to each town’s fiestas patronales — as one clean JSON API for developers, HR and payroll.
Every Spanish public holiday — national, all 17 comunidades, down to each town’s fiestas patronales — as one clean JSON API for developers, HR and payroll.
Spain has 8,132 municipios. Every one has its own holidays.
National holidays are easy. The hard part is that every Spanish town adds its own fiestas patronales, published across a patchwork of official gazettes — and payroll, rotas and delivery promises break on exactly those days. FestivosAPI is the feed we wished existed: national plus all 17 comunidades autónomas plus municipio-level local holidays, served as a clean, versioned JSON API.
DSL4 Digital engineers the dataset, official-source ingestion and API. Viva Grafix’s role was to turn the resulting coverage states, municipality-level precision and documentation into a product interface that developers and operations teams can trust quickly.
The product is deliberately dull to integrate — one key, one call, correct answers. The effort lives underneath.
National → 17 CCAA → 8,132 municipios in one API — the level of granularity Spanish payroll actually runs on.
An OpenAPI 3 spec, an llms.txt for AI agents, tiered rate limiting and API-key plans from €9–19/mo.
Unattended quarterly and annual refresh crons re-parse the gazettes, so next year’s data arrives without anyone remembering to fetch it.
DSL4 Digital turns gazette PDFs and provincial bulletins into deterministic JSON; our job was to make that precision easy to inspect and use.
Local-holiday listings are machine-parsed from official gazettes and joined to the INE municipal registry through an exact name-matcher — the step that turns messy bulletins into a database you can bill for.
The entire product is one Cloudflare Worker with no runtime dependencies — Stripe is integrated over raw WebCrypto rather than an SDK, and pages are self-contained SSR.
Tiered rate limiting, bilingual RGPD-correct legal pages, and 16 node test files guarding the parsers and the API surface.
FestivosAPI is a DSL4 Digital data product: difficult source reconciliation, made usable through clear interface and product presentation by Viva Grafix. The most complete Spanish holidays feed available, refreshed unattended and sold at a price a developer can expense without a meeting.