B2B SaaS / billing
Usage-based billing system
Metering, subscription states, customer portal flows, and webhook handling for a SaaS product moving beyond manual billing.
Senior full-stack & AI engineer
Production SaaS, AI agents & integrations.
I help startups and product teams build the systems their business depends on: SaaS applications, tool-using AI agents, MCP servers, APIs, workflow automation, and payment infrastructure.
10+ years engineeringBuilt a production SaaS productBackend → frontend → APIs → infrastructure
For SaaS founders, CTOs, product leaders, and engineering teams.Based in Karachi · works with distributed teams
Services
Engineering depth where the workflow gets real.
I’m most useful when a feature touches revenue, sensitive data, customers, or the operational backbone of a product.
01 / product systems
SaaS Development
Multi-tenant products, dashboards, RBAC, APIs, queues, billing, and the production details around them.
Explore SaaS development 02 / controlled AIAI Agent Development
Agents that use tools, follow business rules, and leave an understandable trail of what happened.
Explore AI agents 03 / connected systemsMCP Server Development
Practical MCP tools that give AI applications a controlled way to use your APIs, data, and internal systems.
Explore MCP development 04 / operationsAI Workflow Automation
Automate repetitive work with the right mix of deterministic rules, AI steps, integrations, and approvals.
Explore AI automation 05 / reliabilityAPI & Integrations
REST APIs, OAuth, webhooks, retries, idempotency, queues, and integrations that stay legible when things fail.
Explore integrations 06 / revenue systemsPayments & Billing
Subscriptions, gateways, payment states, tokenization, portals, webhooks, and billing edge cases.
Explore paymentsMaybe you’re here because…
The hard part is not finding a framework. It’s making the system hold together.
A good engagement starts with the business problem, then makes the architecture and delivery path visible.
“We need to add AI to an existing SaaS product.”
See AI agent development →“Our tools do not communicate reliably.”
See API & integrations →“Billing edge cases are becoming a product problem.”
See payments & billing →“We need an engineer who can own a feature end to end.”
Talk through the project →“Our MVP needs production architecture, not another demo.”
See SaaS development →“The team spends too much time on repetitive workflows.”
See AI automation →Selected work
Systems shipped with the next engineer in mind.
Selected production work across SaaS, payments, integrations, and product delivery.
Healthcare SaaS / payments
PCI-aware payment vault
Tokenization and Laravel API work that kept raw card data out of more of the application’s own workflows.
SaaS product / agency delivery
Multi-tenant dashboard & API layer
Tenant-aware workflows, permissions, dashboard surfaces, and documentation an existing team could keep owning.
Founder / product proof
ThreatIP is where I operate the full product loop.
ThreatIP is a production B2B SaaS product I built and operate end to end. It spans multi-tenant architecture, AI-assisted decisioning, CRM integrations, billing, dashboards, APIs, infrastructure, and ongoing product operations.
“Irfan quickly implemented the given PHP task and perfectly adjusted to our development workflow with Docker and GitHub Pull Requests.”Verified client review via Upwork · 5.0 rating
ProductLive SaaS experience from architecture through releases.
PaymentsBilling, tokenization, and sensitive data boundaries.
IntegrationsAPIs, CRM workflows, and systems that need context.
Public workGitHub profile ↗ · LinkedIn ↗
Process
Understand → design → build → ship → support.
A direct working relationship, visible progress, and a handoff that does not leave your team guessing.
Understand
Clarify the product, workflow, constraints, and success criteria.
Design
Map the architecture, data flow, integrations, and implementation path.
Build
Develop, integrate, test, and surface decisions while there is still time to change them.
Ship
Prepare for production, verify expected behavior, and document what matters.
Support
Provide handoff, maintenance, or continued engineering as the product needs.
Technical capability
Technology supports the outcome.
The stack stays flexible; the goal is a system your team can understand, operate, and extend.
AI & agent systems
OpenAI · Claude · MCP · tool calling · structured outputs · RAG · agent workflows · human approval flows
Backend
Laravel · PHP · Node.js · Express · NestJS · REST APIs · queues · background jobs
Frontend
React · Next.js · Vue · Angular · JavaScript · dashboards · admin systems
Data & infrastructure
PostgreSQL · MySQL · MongoDB · Redis · Docker · Nginx · AWS
Integrations
REST APIs · webhooks · OAuth · Stripe · payment gateways · third-party SaaS platforms
Engineering practice
Architecture notes · incremental delivery · error handling · observability · maintainable handoff
Start with the problem
Have a system that needs a serious builder?
Send the context, the constraints, and what “done” needs to mean. I’ll tell you quickly whether I’m the right fit and what I’d look at first.