Global App Proposal

Prepared for Hostelling International·June 2026

About us

We create digital solutions for Hospitality Leaders — helping them grow direct bookings and increase guest loyalty.

Founded in 2015, registered in Hong Kong.
Proven track record building & scaling high-traffic websites and mobile apps.
Strong UX / UI foundation with a focus on optimizing conversion.
Highly skilled, specialized team based in the Philippines & Bali.

Selected Work

A selection of recent work relevant to this project.

Jump to a project

RydgesWebsite & Booking Engine04
LyLoWebsite & Booking Engine05
NightskyWebsite & Booking Experience06
QT HotelsWebsite & Booking Engine07
ThredboWebsite & Booking Engine08
ThredboMobile App09
Event CinemasMobile App10
EVT StaysLoyalty Platform11

Selected Work

RydgesWebsite & Booking Engine

Website design & development for a hotel group with 80+ properties.
Booking engine integrated with multiple enterprise PMS sources.

Payments Stripe · Braintree

Visit website

Selected Work

LyLoWebsite & Booking Engine

Website design & development for a modern hostel brand.
Direct-booking engine integrated with the Mews PMS.

Visit website

Selected Work

NightskyWebsite & Booking Experience

Website design & development.
Booking handoff to the Synxis (Sabre) booking engine.

In active development

Selected Work

QT HotelsWebsite & Booking Engine

Website design & development for the QT lifestyle-hotel brand.
Booking engine integrated with enterprise PMS.

Payments Stripe · Braintree

Check booking engine

Selected Work

ThredboWebsite & Booking Engine

Website design & development.
Booking engine integrated with enterprise PMS.

Payments Windcave

Visit website

Selected Work

ThredboMobile App

Design & development, built in React Native.
Used daily by ~50,000 resort visitors.

Selected Work

Event CinemasMobile App

Design & development of the mobile app.
Integration with custom back-end APIs.
UX / UI focused on frictionless ticket and food & beverage booking.
Over 100k monthly active users.

Apple App Store Google Play

Selected Work

EVT StaysLoyalty Platform

Website design & development.
Loyalty system integration.
Custom identity / SSO integration and guest portal build.

Visit website

Understanding your Requirement

Component 01

Global Booking Engine

One embeddable engine, layered over MA systems as the source of truth.

Component 02

Global ID

Federated membership & identity, purchasable inside the booking flow.

Component 03

Global Guest Portal

A unified guest layer over the existing estate — no rip-and-replace.

Initial booking architecture

Booking Engine

Embeddable widget / HI site

Per-tenant, drops into any MA front end.

authenticated checkout · Global ID → see Initial Identity Architecture

Future

AI experiences

MCP server · ChatGPT app · UCP (agentic commerce)

request · clean JSON / REST ↓ ↑ normalised booking data (JSON)

Core

API Layer

Node.js (TypeScript), serverless / edge. One normalised internal booking structure.

ASSD

OTA XML · HTTPS POST

SiteMinder

OTA XML · polling, re-check at booking

Payment provider

tokenised · via PCI proxy

Each PMS / channel sits behind its own adapter — new MAs onboard without core changes.
Adapters normalise different protocols (OTA XML, REST, OIDC) into one internal booking structure.
PMS is the system of record; the API layer exposes one clean JSON structure — consumed by the widget today, and potentially by AI agents (ChatGPT App · UCP · OpenClaw, etc) tomorrow.

Initial Identity Architecture

Identity

Global ID

OIDC / OAuth2 · register · profile · consent · account deletion

authenticate · OIDC / OAuth2 ↓

Relying party

Booking Engine

Authenticated checkout

Relying party

Guest Portal

Authenticated self-service

Future

MA sites / apps

SSO · optional, future-capable

Guest Portal surfaces

Booking history← Analytics
Membership · type · expiry · benefits← Membership database
Digital wallet pass← Wallet Pass Generator

One identity across the network — guests register once and sign in to every HI service (OIDC / OAuth2), with optional MA SSO.
Privacy by design — guests manage profile, consent and marketing preferences, and can request account deletion. GDPR-aligned.
The Guest Portal is a presentation layer — it reads booking history, membership and profile through Global ID, with nothing duplicated.

Security & Compliance considerations

PCI scope minimised — tokenisation, hosted fields.
GDPR consent-driven, with documented deletion.
WCAG accessibility throughout.

Adapter architecture scales MA-by-MA and PMS-by-PMS.
Multi-currency / multi-merchant by design.
API-first foundation.

Delivery Approach

Sprints 1–2

Setup & scaffolding

Stand up HI cloud, ASSD/SiteMinder sandbox and CI/CD; orchestration layer and booking contract. UX/UI in parallel.

→

Sprints 3–8

Build · 2-week sprints

Thin vertical slice first — one MA, one PMS, complete booking — then widen. Global ID + Guest Portal run in parallel.

→

Sprints 9–10

UAT & pilot launch

UAT with HI, hardening, pilot live. Then network rollout, support & maintenance.

Assuming onboarding Mon 3 Aug 2026: sprints 1–2 set up environments and architecture while RSD leads UX/UI, with HI review and sign-off.
We work in two-week sprints — the booking engine is built slice-first, then widened across adapters and MAs.
Commitment: booking-engine pilot live by end of January 2027; the Global ID platform and Guest Portal follow by end of Q1 2027.

Delivery Timeline

Two-week sprints · onboarding Mon 3 Aug 2026 · booking-engine pilot live by end of January 2027.

Environment & sandbox setupHI accounts · ASSD/SiteMinder creds · CI/CD

Architecture & scaffoldingOrchestration layer · booking contract

UX/UI — Booking EngineRSD-led · HI review & sign-off

UX/UI — Guest Portal+ Booking Engine design finalisation

Booking Engine developmentVertical slice first, then widen

UAT & pilot hardeningWith HI UAT resource

Global ID & Guest Portal buildParallel workstream

S1–S2

S3–S4

S3–S8

contingency

S9–S10

if used

S8 → end Q1 2027

S1Aug 3

S2Aug 17

S3Aug 31

S4Sep 14

S5Sep 28

S6Oct 12

S7Oct 26

S8Nov 9

S9Nov 23

S10Dec 7

S11Jan 4

S12Jan 18

S13Feb 1

S14Feb 15

endFeb 26

Tick marks = sprint start dates. Holiday break Dec 21 – Jan 1.

Pilot launch target — late Dec (8-sprint path) Pilot launch commitment — end of January 2027 Holiday break · Dec 21 – Jan 1

Setup & architecture UX/UI design (RSD-led) Booking Engine dev Contingency (10-sprint path) UAT & hardening If contingency used Global ID & Guest Portal

Commercial Model

Capped time & materials — not-to-exceed, phase by phase

Firm commitment on the booking-engine phase; indicative bands beyond.
Cost drivers: number of adapters, languages, identity scale, payment complexity.
You only pay for work delivered — the cap protects your budget.

Scope itemHours (low–high)

Technical discovery / mobilisation40

UX / UI design60–80

Orchestration / API layer + internal booking contract160–180

ASSD adapter140–170

SiteMinder adapter120–160

Booking engine + embeddable widget front-end160–180

Multi-destination single-basket (multi-property cart, split settlement)80–110

Payments (multi-currency, multi-merchant, PCI-minimised)80–100

Membership purchase in-flow + capture / validate-later60–80

Identity — Auth0 sign-in + core Guest Portal140–160

Localisation (4 languages incl. RTL) + WCAG60–80

Testing & QA80–110

Technical PM / coordination70–100

Total1,250–1,550 hrs

IndicativeExecution-only, at US$165/hr — approximately US$206,000–256,000.

Covers the booking-engine pilot plus core identity & Guest Portal. Global ID platform and full Guest Portal continue as the parallel workstream.

Beyond the Build

Optional and ongoing services, priced transparently — no licence, per-booking or per-property fees from our side.

Ongoing

Support & maintenance

from ~US$40kper year · ~20 hrs/month to start

Monitoring, dependency & security updates, PMS-adapter maintenance as upstream APIs change, incident response, and MA onboarding at the configuration level. Hours are flexible and roll over — scale up or top up any time.

On demand

Additional PMS integration

US$16.5k–33kone-off, per platform

Each PMS / channel manager is a self-contained adapter — new integrations don't touch the core engine. Modern REST (e.g. Mews) ≈ US$16.5k–23k; OTA/XML (ASSD-class) ≈ US$23k–33k. Extra MAs on a supported PMS are configuration, not development.

Infrastructure

Hosting — HI-owned, at cost

~US$500–3,500per month · HI pays providers directly

Serverless architecture in HI-owned accounts, no markup. Pilot ≈ US$500–1,000/mo; full network ≈ US$1,800–3,500/mo, scaling with booking volume. Auth0 within its free/entry tier at pilot; indicatively US$800–2,500/mo at full network scale.

The Team

Michiel Waaijer

Founder & Delivery Lead

Vikko Taruc

Senior Project Manager

Adrian Cando

Lead Developer & Architect

Rowel Gutierrez

Lead Developer & Architect

Marco Manigbas

Senior QA

Daryl Magos

Senior Designer

Development Team

Web development · UI engineering · DevOps

Our dev team consists of 8 developers, with the ability to scale up.

Senior Team

Michiel Waaijer

Founder & Delivery Lead

Founded Rock Solid Digital in 2015 and will oversee the project. 12+ years in hospitality digital and booking technology, with hands-on oversight of booking-engine and PMS-integration work at multi-property scale.

Vikko Taruc

Senior Project Manager

Leads delivery, client governance and the Agile development process — backlog, cadence and reporting. 6+ years keeping multi-party builds on track and transparent.

Adrian Cando

Lead Developer & Architect

Back-end and systems integration — Node.js / TypeScript, API design. 10+ years on production booking systems. Co-owns the API layer and PMS / payment adapters.

Rowel Gutierrez

Lead Developer & Architect

Deep PMS-integration expertise — Opera, Mews and OHIP-class migrations. 5+ years in hospitality systems. Co-owns the ASSD / SiteMinder adapters.

Daryl Magos

Senior Designer

Leads UX / UI for the widget and guest portal — conversion-focused, mobile-first, WCAG-accessible. 6+ years in booking interfaces.

Marco Manigbas

Senior QA

Owns QA across booking, payment and identity — test strategy, integration harnesses and UAT. 10+ years in software QA.

What our clients say

“

I've worked with Michiel Waaijer and Rock Solid for nearly a decade, and they've become an indispensable partner — deeply understanding our booking engine, web architecture, and the unique needs of the hotel industry. They've built and maintained a WordPress network supporting over 80 hotels across Australia, New Zealand and Singapore, consistently delivering complex, customized solutions that exceed expectations. Rock Solid makes my work dramatically easier while significantly enhancing our capabilities as a hotel management company — collaborative, flexible, and seamlessly integrated into our workflows.

David TuzaGM Digital — Hotels · EVT

“

Event Cinemas have partnered with Rock Solid to deliver what is now a best-in-class mobile experience. The team truly care about our digital platform and have always delivered on time and on budget. We look forward to building more amazing experiences with Rock Solid in the coming years.

Andrew TurnerGroup General Manager, Technology & Digital · EVT

Future Fit

HI's stated direction is AI smart search, AI-driven discovery and AI-agent commerce. We have active capability already in development for other clients.

In development

MCP servers

Model-context endpoints that expose booking capability to AI agents.

In development

ChatGPT app

A conversational front door to the booking experience.

In development

Agentic-commerce protocol

Standards support so agents can transact directly.

Our API-first foundation makes HI ready for agentic commerce.

UI Demo

We put together a small initial demo of how the Booking Engine widget could look on a HI network site. Key features:

Full-screen overlay — booking completes entirely within the modal.
AI Assist mode to quickly answer user questions.
Initial UX / UI shown for the first screen — the full hostel-centric flow to be worked out in the UX / UI phase.

Live demo

Thank you

We look forward to working with you and finalising the scope of the project.

Michiel Waaijer

Founder · Rock Solid Digital