HostMost // Event & group finance app · iOS & Android
Event planning, shared expenses and a poker chip ledger — in one app
Group events — game nights, poker evenings, shared trips, team outings — involve three recurring headaches: coordinating who is coming, splitting costs fairly, and chasing people for money afterwards. Most groups solve this with a combination of WhatsApp threads, spreadsheets, and Revolut requests. It works until it does not.
HostMost was built to collapse that stack into a single mobile app. The product vision was straightforward: one place from invitation to final payment. The engineering challenge was anything but — this is a social product, a finance product, and a real-time collaboration product simultaneously, with a niche vertical feature (a full poker chip ledger) layered on top.
The product surface
The product is organised across six feature domains, each with dedicated API, UI, hooks, and types. The breadth is significant — this is not a simple CRUD app with a chat bolted on. The finance system is the most technically demanding module: rather than ad-hoc calculations, it is built on explicit ledger primitives, with a greedy settlement plan algorithm that proposes the fewest transactions needed to zero all participant balances.
Events
Create, edit, role assignment, status workflow, activity feed, media gallery, polls and reminders. The host's command surface — built before anything else because everything else depends on it.
Connections
Social graph with search, email-based invite funnel, blocking and reporting. Hosts can invite friends not yet on the platform; pending invitations auto-resolve into connections on signup.
Venues
House listings, availability windows, access control, image galleries and event linking — letting frequent hosts build a reusable library of locations.
Finances
Expenses, splits, balances, settlements, fee rules, freeze controls and cross-event debt — built on a proper ledger, not UI-level arithmetic.
Poker chips
Buy-ins, cash-outs, requests, approvals, void/correction and materialised balances — a first-class backend concept, not a hack layered on top of expenses.
Messaging
DMs, event group chats, real-time sync, read state, push notifications and email digests — the live tissue holding the rest of the product together.
Decisions, not just dependencies.
The mobile client follows a feature-based modular structure under Expo Router — file-based routes in app/, business logic per domain in features/, shared primitives in components/. TanStack React Query manages all server state; Supabase Realtime subscriptions feed live finance and chat updates directly into the query cache without polling. The React Native New Architecture is enabled in production.
The backend runs entirely on Supabase: 70+ incremental PostgreSQL migrations, RLS on every sensitive table, database triggers for chip balance materialisation and fee-rule calculations, eight Deno Edge Functions for serverless logic, and pg_cron for reminder and email digest scheduling. Builds and OTA updates are managed through Expo Application Services with isolated development, preview and production profiles.
What was hard, and how we shipped it.
- 01
Full greenfield mobile product shipped to both stores
iOS App Store and Google Play, EAS build profiles, OTA update channel, and store deployment runbooks — the complete production release pipeline built and operated by Coralsoft from v1.0 to v1.1.31.
- 02
Multi-party debt settlement engine
A greedy settlement plan algorithm reduces N-way balances to the minimal set of actionable payments, with admin controls to lock edges, split payments, and reassign creditors before committing — built on a proper ledger model, not UI-level arithmetic.
- 03
Poker chip domain as first-class backend concept
An append-only chip transaction log with database-maintained materialised balances, request/approval workflows, and void/correction with full audit fields — not a UI hack layered over the expense model.
- 04
Real-time collaborative finance
Multiple users viewing an event's ledger see expense, balance, and settlement updates propagate instantly via Supabase Realtime — no refresh required, no stale totals when a host and guest are settling simultaneously.
- 05
Email-to-connection growth funnel
Hosts invite friends not yet on the platform by email; when those users sign up, a pending invitation is automatically resolved into a connection — closing the loop without manual matching and providing a built-in acquisition channel.
Looking at a project that sits at this kind of seam?
Bring us the architecture, the constraints, and the ship date. We will bring the rest.