Engineering
Custom Software Development
Platforms, back offices and integrations built to run for years: .NET and Python services, queues, payments, real-time delivery, and the APIs an AI system will need.
At a glance
- Platforms that keep running: queues, retries, idempotent ledgers
- Payment, supplier and partner API integrations
- Back offices and admin tools for the people who run the business
- Designed so AI agents can be added later without a rewrite
Momentaj, a Toronto AI engineering firm, builds custom software: platforms, back offices and integrations meant to run for years. Most of what an AI system does is call ordinary software: a booking engine, a ledger, an inventory, a CRM. If that software is fragile, the agent is fragile. We build the platforms underneath, and we build them so an agent or an MCP server can be added later without a rewrite.
What we build
- Platforms and back offices. Multi-tenant systems with role-based access, audit history, reporting and the admin tools staff actually use.
- API integrations. Supplier, payment and partner APIs, REST and SOAP, with retries, idempotency and the monitoring to know when a partner is down. Amadeus, Hotelbeds, Stripe, Moneris and a dozen more on one platform alone.
- Payments and ledgers. Double-entry ledgers that cannot post twice, instalment and Buy Now, Pay Later flows, 3-D Secure and fraud checks.
- Real-time delivery. WebSocket and SignalR streams, queues between every layer, bulk writes for high-volume data.
- AI-ready design. Clean service boundaries, typed APIs and event logs, which are exactly what an agent or an MCP server needs later.
How it's done
Requirements with the people doing the work, an architecture you can read, iterative delivery with working software every few weeks, automated testing, and a handover your own team can own. C#, .NET and ASP.NET Core; Python; MongoDB, PostgreSQL and SQL Server; RabbitMQ and Redis; Svelte, Blazor, React and Angular on the front.
Proof
Trip Support: one booking platform for flights, hotels, packages, insurance, tours and Buy Now, Pay Later, with fifteen integrations in two currencies and two languages. Private Lending Platform: investor wallets, automated matching and a ledger built so that no payment can be posted twice, in production.
Frequently asked questions
Do you take over existing software systems?
Yes. We start with an architecture review, stabilise what is fragile, and then extend. Several of our platforms were inherited mid-flight.
Which technologies do you use for custom software?
Mostly .NET on the server, Python where data and models live, MongoDB or PostgreSQL for data, and Svelte, Blazor or React on the front end. We choose what your team can maintain.
Can an AI agent be added to custom software later?
Yes, if the platform is built for it. An agent's tools are made from clean APIs, typed contracts and clear permissions, so we design for those from the start and adding an agent later does not need a rewrite.
What kinds of software systems have you built?
Platforms that run businesses: a national travel booking platform with 15 integrations, a private lending platform whose ledger cannot post a payment twice, and a real-time tracking system for the Department of National Defence.
How much does custom software development cost?
Each stage has its own price, agreed before it starts, rather than a published rate card, because the cost depends on your workflows, your data and the systems in scope. Discovery is a fixed price based on the number of workflows and systems in scope, and each later stage is quoted before it begins.
Do you work with companies outside Toronto?
Yes. We work remotely with clients across Canada, the United States, the Middle East and beyond, and in person across the Greater Toronto Area.
Related services
Cloud & DevOps
Azure and AWS infrastructure for AI and platform workloads: identity, API management, observability, CI/CD and cost control, as code.
IoT & Connected Systems
Devices, radios and the cloud that receives their data: BLE, LoRa and LTE-M hardware, MQTT ingestion, real-time dashboards and the analytics on top.
Web & Mobile Development
Fast, accessible web apps and mobile-first PWAs in Blazor, SvelteKit and React, designed with the people who will use them.
Talk to the people who would build it
Tell us what you are trying to build. We will come back with an honest take and a plan.
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