Routeory

Routeory is organized as a monorepo containing a high-throughput backend service and an offline-ready mobile application:

• Backend API Engine (backend-api): Built with NestJS and the Fastify HTTP platform adapter for maximum request throughput and low serialization overhead. Prisma ORM interfaces with PostgreSQL, and Socket.io powers bi-directional event distribution. • Mobile Client Stack (mobile-app): React Native built on Expo SDK 56 with Expo Router file-based typed routing, NativeWind v4 styling, Zustand global state, TanStack React Query v5 server caching, and hardware-backed Expo SecureStore for JWT tokens. • Direct-to-Cloud Upload Pipeline: To keep backend nodes bandwidth-free, the mobile client requests presigned HMAC SHA-256 signatures from GET /media/signature and uploads images/videos directly to Cloudinary, submitting only media URLs and metadata to the database.

The CollaborationGateway synchronizes expedition activities across all active co-travelers:

• Handshake Token Authentication: Extracts and verifies JWT credentials from socket connection headers before granting room access. • Multi-Room Event Routing: - user:<userId>: Dedicated private room for real-time invitations, friend requests, and individual alert payloads. - trip:<tripId>: Broadcast channel for active co-travelers on a specific journey. • Event Mesh: Broadcasts timeline_update → on_timeline_update and budget_update → on_budget_update across the crew room. • Offline Resilience: Local Zustand stores maintain mutation queues while off-grid; when network connectivity returns, drafts are flushed sequentially and React Query invalidates cached timeline slices.

Expeditions are structured into chronological dayNumber buckets with support for multi-modal milestone entries:

• Photos & Media: High-resolution assets with Cloudinary public IDs, dimensions, and optimized thumbnails. • Quick Notes: Ephemeral thoughts and trail observations. • Geocoded Places: Linked geographic pins with Google Place IDs, addresses, and GPS coordinates. • Linked Expenses: Financial records tied directly to timeline events. • AI Journal Cards: Beautifully formatted editorial summaries generated for each day.

Entries support offline timestamp recording and re-ordering, slotting seamlessly into historical sequence upon synchronization.

Routeory manages complex multi-party travel budgets with extreme precision:

• Multi-Currency Split Ledger: Records expenses with high precision (Decimal(12, 2)), currency codes, category tags (Food, Accommodation, Transport, etc.), and custom or equal split allocations. • Greedy Minimal-Transaction Algorithm: 1. Computes Net Balance for each traveler: NetBalance[i] = TotalPaidBy[i] - TotalOwedBy[i]. 2. Partitions travelers into sorted lists: Creditors (NetBalance > 0 descending) and Debtors (NetBalance < 0 descending by absolute debt). 3. Executes a two-pointer reduction loop matching top creditors with top debtors, eliminating circular transfers and resolving all crew balances with the absolute minimal transaction count.

The AiService turns raw chronological logs into literary travelogues:

• Context Aggregation: Collects all notes, places visited, media captions, and expense summaries for a specified dayNumber. • Prompt Engineering: Structured system instructions emphasize vivid travel prose, sensory detail, tone selection, and an evocative one-sentence summary caption. • Atomic Storage: Saves the synthesized narrative in the Journal database table inside an atomic transaction, generating a JOURNAL timeline card. • Fallback Pipeline: Operates with a deterministic procedural narrative generator when running in offline or sandbox environments.

The ReplayService generates animated expedition playback packages:

• Intelligent Geospatial Caching: Waypoint coordinates are rounded to 5 decimal places (originKey, destKey) and checked against the PostgreSQL RouteCache table (30-day TTL). On cache misses, OSRM turn-by-turn routing coordinates are retrieved and stored as GeoJSON polylines. • Animated Map Controller: The mobile client utilizes useReplayTimelineEngine to smoothly interpolate map camera pitch, heading, waypoint progress markers, and zoom levels across playback speeds (1x, 2x, 4x).

Travelers can export and showcase their memories across multiple formats:

• Visual Story Templates: Features pre-built designer templates including Polaroid (nostalgic frame with handwritten caption notes), Editorial/Magazine (modern typographical showcase), and Minimalist (clean photo display with coordinates). • Native Canvas Capture: Uses react-native-view-shot to render off-screen components into crisp PNG/JPEG files and triggers expo-sharing for instant Instagram or WhatsApp dispatch. • Public Web Publishing: Trip owners can publish public chronicles via unique PublicStory slugs, rendering responsive web views for friends and family.

The backend persistence layer is built on PostgreSQL with Prisma ORM:

• High-Performance Indexing: High-cardinality compound indices on [tripId, loggedAt], [userId, createdAt], and [ownerId], alongside unique constraints on [tripId, userId] (collaborators) and [expenseId, userId] (splits). • Fastify HTTP Advantage: Replaces standard Express with Fastify, doubling route execution throughput and minimizing JSON serialization latency. • Stateless Architecture: Decoupled socket rooms and JWT session handling allow seamless horizontal node clustering behind a Redis Pub/Sub adapter.

Shipped a production-grade full-stack travel operating system combining mobile native ergonomics, real-time collaboration, and automated narrative intelligence.