Technical Specifications

Engineered for durability, isolation, and longevity.

A comprehensive look under the hood at how Nostos structures database tenancy, private object storage, automated recovery, and sovereign data portability.

Persistence Engine

Multi-Tenant Database Isolation

Database-per-customer tenancy

In Nostos Hosted, each customer account is mapped server-side to its own isolated PostgreSQL database. The control plane owns that account-to-database mapping; clients never choose database identifiers or tenant namespaces themselves.

Self-Hosted SQLite parity

Self-Hosted Nostos uses the same product model with a local SQLite database. SQLite and PostgreSQL keep provider-specific migration lifecycles while sharing the canonical domain model and product behavior.

Database Specs

Hosted Engine: Managed PostgreSQL on Neon
Isolation Level: Dedicated PostgreSQL database per customer
Self-Hosted Engine: Local single-file SQLite (WAL mode)
Portability: Provider-independent .nostos archive between Hosted and Self-Hosted

Media Delivery

Object Storage & Authorized Delivery

Durable object storage

Hosted book files, covers, PDFs, EPUBs, and audiobooks live in S3-compatible Backblaze B2 rather than on the application container. Tenant ownership is resolved by the hosted backend before an object is read or written.

Delivery today, direct delivery when needed

Media is currently served through the authenticated Nostos application path. Short-lived direct object delivery is a scale optimization for heavier media traffic, not a capability the architecture page should claim before it is deployed.

Storage Specs

Hosted Storage: S3-compatible Backblaze B2
Delivery Mode: Authenticated application delivery today; authorized direct delivery is a scale optimization
Self-Hosted Storage: Direct filesystem storage on local disk
Tenant Boundary: Object keys and namespaces are derived server-side

Data Resilience

Portable Backups & Provider Recovery

Two separate recovery layers

Nostos creates daily tenant-scoped portable backups that include customer library data and stored media. The PostgreSQL provider supplies a separate infrastructure recovery layer. Provider recovery never replaces the tenant-level backup and restore path.

Customer-owned portability

Hosted customers can export the same provider-independent .nostos archive used for Self-Hosted portability. The archive carries structured library data and stored media without exposing PostgreSQL internals, provider snapshots, or account credentials.

Backup Specs

Customer Backup: Automated daily portable archive
Provider Recovery: Neon restore history / point-in-time recovery on the production plan
Export Format: Provider-independent .nostos archive
Restoration: Staged Hosted recovery or import into Self-Hosted Nostos