Local-First Offline Computation and the Swiss Ephemeris WASM Architecture
Your birth data stays in your own browser's local storage: it's never uploaded to a server, and closing the tab erases it.
Written and reviewed in house by the AstroStarCheck research team. Astronomical positions come from the Swiss Ephemeris; interpretive rules are checked against the classical texts listed under Sources.
The Sensitivity of Natal Telemetry: High-Precision Space-Time Digital Fingerprints
In the contemporary digital ecosystem, an individual's exact year, month, day, minute-level birth timestamp, and geographic coordinates constitute a uniquely identifying biometric fingerprint. Combined with personal relationship dossiers, synastry charts, and confidential reflective journals, this telemetry represents exceptionally sensitive personal data. If transmitted to centralized cloud servers, it risks becoming raw material for commercial tracking, identity profiling, or malicious data breaches. Most conventional astrology platforms rely on a centralized client-server model (input on client, compute on cloud, return output) to minimize engineering complexity, inadvertently depriving users of sovereignty over their most private personal history.
The Local-First Paradigm: Returning Computational Sovereignty to the Edge Device
AstroStarCheck was engineered from its inception around the foundational philosophy of Local-First computing. Under this architectural paradigm, the user's local device (whether a personal computer, tablet, or smartphone) functions as an autonomous, self-contained computational engine. The entire analytical pipeline (including birth timestamp conversion, orbital calculation of ecliptic coordinates, house cusp geometry, and multi-layered predictive timing matrices) executes entirely within the browser's local sandbox. From the moment data is entered, it never leaves the physical confines of the client device, permanently eliminating the vulnerability vectors inherent in cloud database storage and public network transmission.
Swiss Ephemeris and WebAssembly: Bringing High-Performance Astrophysics to the Browser
Executing sub-arcsecond planetary orbital calculations directly inside a web client was made possible by compiling the Swiss Ephemeris to WebAssembly (WASM). Developed by Astrodienst, the Swiss Ephemeris is the gold standard C library for planetary and lunar ephemerides based on JPL numerical integrations. By optimizing and compiling this extensive C codebase into a compact WASM binary module via Emscripten, AstroStarCheck delivers near-native computational execution speed within the browser engine. The client computes high-precision planetary coordinates, house cusps, and astronomical stations in milliseconds, completely bypassing the need for cloud-hosted calculation APIs.
Zero-Transmission Network Isolation: Verifiable Air-Gapped Operational Capacity
The definitive proof of authentic privacy engineering is complete offline functionality. AstroStarCheck operates as a modern Progressive Web App (PWA) with deterministic static asset caching. Once the initial HTML, CSS, JavaScript, and compiled WASM binary modules are loaded via HTTPS, the platform requires no further network connection. Users can disconnect their internet connection, enable airplane mode, and continue entering charts, shifting house systems, and generating secondary progressions or solar arcs without interruption. Inspecting the browser's Network Panel verifies that zero HTTP requests are transmitted during chart calculation, confirming absolute network isolation.
Sandboxed Local Storage and Cryptographic Data Sovereignty
To enable users to save and organize multiple chart profiles and personal case notes without cloud vulnerability, AstroStarCheck utilizes browser-native IndexedDB and LocalStorage technologies. All profile records are stored strictly within the secure client sandbox governed by the Same-Origin Policy. The application contains no covert cloud telemetry, requires no invasive phone or social logins, and executes no cross-site tracking. Users retain absolute custody over their archives, with the ability to export complete JSON backups at any time or execute a single-click purge to permanently erase all local records.
LLM Dialogue Privacy Sanitization: Feature Abstraction and PII Stripping
When users opt to utilize AI-assisted interpretative features, the application processes the chart data through an automated client-side sanitization pipeline. Before any prompt is sent to an external language model API, the local engine systematically strips away all Personally Identifiable Information (PII), including names, exact birth dates, precise timestamps, and geographic coordinates. The system abstracts the chart into mathematical and symbolic configurations (such as 'Sun in Aries at 15 degrees in House 10, square Saturn in Capricorn'). This edge-computed sanitization ensures that users benefit from advanced AI synthesis without exposing sensitive biographical data to third-party providers.
Verifiable Transparency and Open Architecture: Ethics in the Digital Era
In modern software design, genuine privacy cannot rest upon unverified corporate assurances; it must be demonstrably built into system architecture and open to technical inspection. AstroStarCheck welcomes independent verification of its network activity and execution pipelines. In an era dominated by data monetization and commercial profiling, empowering individuals with absolute digital sovereignty is not merely a technical accomplishment, but an ethical obligation. Client-side offline computation ensures that the ancient pursuit of self-understanding remains safe, dignified, and entirely private.
FAQ
Why does compiling the Swiss Ephemeris to WebAssembly guarantee data privacy?
The Swiss Ephemeris is a high-performance C library. Compiling it to WebAssembly allows it to run directly on your device's CPU inside the browser. Because calculations occur locally, your birth data never needs to travel to a cloud server to obtain astrological coordinates, eliminating the risk of data interception.
Can I use AstroStarCheck when completely disconnected from the internet?
Yes. After the initial page load, all calculation engines (charts, house systems, progressions, solar arcs, Firdaria) execute entirely on your device. You can use all core features seamlessly while in airplane mode or with your network disconnected.
Does AstroStarCheck transmit my geographic coordinates or birth records to any analytics server?
No. Your birth timestamp, location coordinates, and saved profiles remain strictly within your browser's local IndexedDB and LocalStorage sandbox. You can verify this at any time using your browser's Developer Network tab.
Will my saved astrological charts be lost if I clear my browser cache or switch devices?
Because data is stored exclusively in your local browser sandbox, clearing website storage or deleting the browser will remove local charts. We strongly recommend using the built-in 'Export Data' tool to save JSON backup files to your own secure storage.
What specific chart data is transmitted when I use the optional AI dialogue features?
The system runs an on-device sanitization routine that strips your name, birth date, time, and coordinates. It transmits only abstracted symbolic data (such as 'Sun in Leo in 10th house conjunct Jupiter') to ensure no personally identifiable information reaches the AI provider.
Sources and further reading
Astronomical positions and interpretive rules on this page are checked against these works.
- Swiss Ephemeris programmer's documentation (computation parameters and API reference)
- NASA Science, Solar System