RESEARCH INTEGRITY / AGENT TOOLS Released · MIT
RefExists
Citation verification for researchers and AI agents. RefExists checks scholarly records, matches titles and authors, and explains the evidence behind each result.
INDEPENDENT SOFTWARE & AI COMPANY
We build and operate
software products.
From neural speech to tools that rescue your work.
We design, develop and own digital products —
and the technology that makes them work.
DSL4 DIGITAL · CANARY ISLANDS, SPAINPRODUCTS / PLATFORMS / R&D
01 / SELECTED PRODUCTS
Software with a purpose.
AI / LANGUAGE LEARNING Released
Versos
Versos turns poetry into a language-learning platform: read real poems, hear them in native voices, reveal translations line by line and return with spaced repetition.
BROWSER / DATA RECOVERY Released · MIT
Mendery
Recover readable content from damaged documents and SQLite files directly in the browser, without uploading the file.
DEVELOPER TOOLS / COMMERCE Released
Papertill
A compact digital-download checkout that brings payments, licence keys and expiring delivery links into one Cloudflare Worker.
AI AGENTS / INTERACTIVE 3D R&D / Beta
BotBalls
A persistent virtual sphere where humans and AI agents participate through an interactive 3D interface and agent tooling.
LEGAL TECH / EVIDENTIARY PIPELINES In development
ThreadCase
A privacy-first evidence pipeline and case-pack compiler: ingest multi-source records, establish cryptographic provenance, and extract chronological event threads without third-party data leakage.
DATA PRODUCTS / CLOUDFLARE WORKERS + D1
ConvenioAlert
A monitoring platform for Spanish collective labour agreements, connecting official records, sector classification, salary-table extraction and targeted alerts.↗Subvenio
Public-grant discovery built around relevant opportunities: official-source ingestion, regional and sector filters, translated information and deadline reminders.↗FestivosAPI
Spanish national, regional and municipal holiday data through a JSON API, built for payroll, scheduling and applications that need to understand local working days.↗02 / UNDER THE SURFACE
The product is only
part of the build.
A learning platform, spoken aloud.
Versos connects a growing poetry library to GPU speech generation, cached audio and repeatable practice — a foundation for more languages, voices and learning paths.
Small systems. Real work.
Papertill handles payment and digital delivery in one Worker. Mendery recovers document content inside the browser.
Built for traceability.
Newsroom records content provenance. ThreadCase and BotBalls explore verifiable protocols and cryptographic proof.
03 / INDEPENDENT BY DESIGN
Built in the Canary Islands.
Made for the web, and your devices.
DSL4 Digital, S.L.U. is an independent software and AI company based in Spain. Our work spans language learning, developer tools, automation and experimental digital platforms.
About DSL4 ↗