In the burgeoning world of "Software as a Service," the difference between a market leader and a failed startup often comes down to the underlying architecture. DataStream Analytics, a London-based fintech startup focused on real-time market sentiment, had a revolutionary algorithm but a "proof of concept" that couldn't scale. Their initial MVP was built on a fragmented tech stack that crashed under moderate traffic, preventing them from securing the enterprise-level contracts they needed in the City and Canary Wharf.
They partnered with Custom Coded Websites to rebuild their platform from the ground up as a robust, enterprise-grade SaaS application. Here is how we used Python and Django to turn their vision into a scalable, revenue-generating engine.
The Challenge: Building for Infinite Scale
DataStream Analytics wasn't just building a website; they were building a tool that needed to process millions of data points and serve them to thousands of concurrent users. Their primary challenges were:
- Multi-Tenancy Requirements: They needed a way to isolate customer data securely while running off a single application instance to keep overheads low.
- Performance Latency: Real-time financial data is worthless if it arrives late. Their existing system had a 4-second delay that was unacceptable for institutional traders.
- Subscription Management: They lacked a secure, automated way to handle tiered billing, trial periods, and seat-based licensing for their corporate clients.
The CCW Solution: A Multi-Tenant Django Powerhouse
Our co-founders, Charlie Shortman and Louie Long, designed a "Clean-Slate" architecture using the Django framework. Django was the logical choice due to its maturity, security-first philosophy, and its ability to handle complex data models through its powerful ORM.
1. Multi-Tenant Architecture & Data Isolation
Charlie Shortman engineered a Schema-based multi-tenancy system using PostgreSQL. This ensured that while all clients shared the same application code, their data was stored in isolated database schemas. This "Silo" approach provided the high-level security and data privacy required by financial firms in Shoreditch and Westminster, while allowing DataStream to update the platform for all users simultaneously.
2. High-Velocity Data Processing
To solve the latency issue, we implemented a custom data pipeline using Django Channels and Redis. This allowed for real-time, bi-directional communication between the server and the client's browser via WebSockets. We moved the heavy mathematical computations to background workers using Celery, ensuring that the user interface remained lightning-fast even during periods of extreme market volatility. The "Time to Data" was reduced from 4 seconds to under 200 milliseconds.
3. Seamless Stripe Billing Integration
Louie Long designed and integrated a custom Stripe Billing engine. We built a bespoke "Subscription Dashboard" where users could upgrade tiers, manage team seats, and view invoices without leaving the app. We automated the entire lifecycle—from the 14-day free trial to the professional and enterprise tiers—virtually eliminating manual billing administration for the DataStream team.
The Results: From MVP to Enterprise Leader
The transformation of the DataStream Analytics platform yielded immediate results in the competitive London tech market:
- User Capacity: The platform successfully scaled from 100 users to over 10,000 active subscribers without a single minute of unscheduled downtime.
- Enterprise Adoption: With the new secure architecture, the startup secured three major contracts with City-based hedge funds within the first six months.
- Development Velocity: By using clean, documented Django code, the internal team was able to deploy new features 50% faster than with their previous stack.
- Investment Success: On the back of the platform's stability and growth, DataStream Analytics successfully closed their Series A funding round.
Why Founders Choose Django for SaaS Development
DataStream Analytics' success highlights why Django is the preferred framework for modern SaaS startups. At Custom Coded Websites, we don't just "build apps"; we engineer long-term business assets. Our custom-coded approach ensures you aren't paying "per-user" fees to a platform, and you own every line of your intellectual property.
Based in London, we specialize in taking startups from their first 10 users to their first 10,000. We build the digital infrastructure that makes scaling look easy.