We build the software your business runs on

Crestline Solutions designs and engineers web applications, mobile apps, social platforms, voice chatrooms, and custom SaaS portals, from first idea to millions of users.

Start a project See what we build

Engineered with

Next.js
React Native
Flutter
Node.js
PostgreSQL
WebRTC

app.yourbrand.com/rooms/night-lounge

Night Lounge

ID 482139 1,284

musicLive

Omar sent Rocket to Maya

×3

1
Maya
2
Omar
3
Lena
4
Theo
5
Sara
6
Ravi
7
Ines
8
Join seat

Say something... Gift

Room chat

128 online

Lena Welcome everyone to the lounge
Sara This track is perfect tonight
Omar sent Rocket ×3 to Maya
Theo requested seat 8AcceptDecline

Top gifters

Today

1Omar Haddad48,200
2Sara Kim31,950
3Ines Costa12,400

Latency: 42ms
Bitrate: 64k
Region: EU-W

Live audio rooms with host seats, speaker detection, chat, and gifting leaderboards.

Sub-100ms audio
Seat & mic moderation
Gift animations

WebRTC
Realtime
In-app coins

Services

Software built around your business

From a first prototype to a platform serving millions, we design, build, and run the product with you.

Web applications

Production-grade web applications built on Next.js and React, engineered for speed, SEO, and long-term maintainability.

Next.js & React
Server-rendered & SEO-ready
Accessible, responsive UI

Mobile apps

Native-quality iOS and Android apps from a single codebase, with store submission, push notifications, and in-app purchases.

Flutter & React Native
App Store & Google Play release
Push & in-app purchases

Voice chatroom apps

Real-time voice rooms with host controls, speaker seats, live gifting, leaderboards, and low-latency audio that scales to thousands.

Low-latency WebRTC audio
Seats, hosts & moderation
Gifting, coins & events

Custom SaaS portals

Multi-tenant SaaS products with subscriptions, team workspaces, role-based access, usage billing, and analytics built in.

Subscriptions & billing
Teams, roles & permissions
Usage analytics

Client & admin portals

Customer portals, partner dashboards, and back-office admin panels that replace spreadsheets and connect your existing systems.

Self-service client areas
Admin & reporting panels
Integrations & exports

The hard parts, already solved

Real-time audio, payments, roles, and analytics are where most projects stall. We bring proven building blocks so your budget goes into what makes your product different.

Real-time & streaming

WebRTC audio and video, WebSockets, presence.

Latency tuned for live rooms

Payments & wallets

CheckoutReady

SubscriptionsReady

Virtual coinsReady

PayoutsReady

Auth & permissions

OwnerFull access
AdminManage team
ModeratorReview content
MemberStandard

Admin & analytics

Back-office dashboards, reporting, CSV and PDF exports, and audit logs for every action.

AI integration

Assistants, content moderation, search, and workflow automation wired into your product.

Cloud & DevOps

Managed hosting, CI/CD, backups, monitoring, and alerting, so your app stays fast and online.

A clear process,
from idea to launch

One dedicated team owns your product end to end. You always know what is being built, what it costs, and when it ships.

You own everything

Full source code, designs, and accounts are transferred to you. No lock-in.

Fixed-scope proposals

Weekly progress demos

Dedicated project lead

UK-registered company

Delivery roadmap

01Discover
Workshops to define users, scope, and a fixed delivery plan.
02Design
Clickable prototypes and a design system you approve before build.
03Build
Two-week sprints with a live preview link and a demo every week.
04Launch & support
Store submission, go-live, monitoring, and ongoing improvements.

Automated testing

Security reviews

Performance budgets

Documentation & handover

Source code ownership: 100%
Live demos & preview links: Weekly
One team, every platform: iOS · Android · Web
Registered in England & Wales: UK

Ways to work with us

Every engagement starts with a free consultation and a written proposal.

Best for MVPs and new products

Fixed-scope project

Agreed scope, price, and timeline
Design, build, and launch
30 days of post-launch fixes

Best for growing platforms

Dedicated team

Engineers, designer, and project lead
Monthly capacity you can reprioritise
Ideal for social and voice apps at scale

Best for live products

Support & evolution

Monitoring, updates, and security patches
Guaranteed response times
Small features every month

Frequently Asked Questions

Can't find the answer you're looking for? Get in touch and we'll reply within one working day.

Have a product in mind?

Tell us what you want to build. We'll come back with next steps and a free consultation.

01
We reply within one working day
A senior engineer reads every enquiry, not a sales bot.
02
Free 30-minute consultation
We talk through goals, users, scope and the right stack.
03
Fixed proposal in a week
Clear milestones, timeline and cost before any work starts.