FinTech SaaS Application Architect

SUMIT KUMAR

Application Architect Solution Architecture, SaaS and FinTech Platforms

Bengaluru, India +91-880******* *****.*****@*****.*** linkedin.com/in/sumit22 github.com/sumit22 SUMMARY

Application architect with 14+ years in software engineering, 9 of them in architect and lead roles, mostly in fintech

(banking, payments, cards, crypto). Takes systems from requirements to production: working with business and client stakeholders, choosing the architecture and stack, designing components and AWS infrastructure, and writing the specs teams build from. Currently founder of SutraOS, a member of the NVIDIA Inception program, building multi-tenant SaaS and AI products with LLM and text-to-speech integrations. Has delivered against PCI DSS, GDPR and RBI compliance, modernised legacy platforms, and led teams of up to 7 engineers. SKILLS

Architecture Solution architecture, system design, microservices, modular monolith, event-driven architecture, Domain-Driven Design (DDD), multi-tenant SaaS, legacy modernisation, design patterns, SOLID, Clean Architecture, 12-factor apps; C4, UML, ADRs, REST API specifications

Languages & Frameworks PHP (Laravel, Symfony), JavaScript, TypeScript, Node.js (NestJS, Express), React, Next.js, Vue.js, Core Java, Go

Databases & Search PostgreSQL, MySQL, MongoDB, Redis, Firebase, Apache Solr; schema design, indexing, query optimisation, caching; ORMs: Doctrine, Eloquent, TypeORM, Prisma Cloud & DevOps AWS (EC2, S3, SQS, SNS, SES, IAM, VPC, Auto Scaling, CodeDeploy), Docker, CI/CD

(GitHub Actions, Jenkins), Git, APM, centralised logging, alerting Security & Compliance OWASP Top 10, authentication and authorisation (RBAC/ACL), encryption at rest, rate limiting, vulnerability remediation, PCI DSS (SAQ-A), GDPR, RBI/banking compliance AI & LLM LLM APIs (OpenAI, Anthropic Claude, Google Gemini), prompt design and output evaluation; text-to-speech (ElevenLabs, OpenAI, Google Cloud TTS, Edge TTS, Windows SAPI, self-hosted Piper); image generation (fal.ai Flux); Google Vision API, TensorFlow.js face detection

Integrations Google OAuth 2.0, Firebase (Authentication, Firestore, Realtime Database); payments: Stripe (Connect), Razorpay, RevenueCat; cards and banking: MatchMove, Rapyd, bank partner APIs; YouTube Data API, Instagram; messaging: Twilio, SendGrid, Resend, AWS SES, push notifications

Leadership Stakeholder management, design and code reviews, mentoring, hiring, Agile/Scrum EXPERIENCE

Founder & Principal Engineer, SutraOS Sep 2025 – Present NVIDIA Inception program member. Sole architect and engineer for live SaaS and AI products, owning design, delivery, operations and AWS cost

SutraOS: multi-tenant B2B SaaS platform

Architected the platform as a modular monolith of 17 domain modules using DDD. Modules communicate only through queued events or published interfaces, so any module can be split into its own service later without a rewrite.

Built subdomain-based multi-tenancy with tenant isolation enforced twice, at the API gateway and again in the application layer, so a bug in one check cannot expose another tenant's data. Turned architecture rules (module dependencies, API response and error contracts, latency budgets, encryption and secrets handling) into automated tests that fail the CI build when a rule is broken. SalonOS: white-label multi-tenant SaaS for multi-location salons and service businesses Designed a marketplace-plus-tenant model: each chain gets its own branded storefront on a subdomain, while customer accounts stay platform-level to allow cross-tenant discovery without sharing tenant data. Built the booking and availability engine: multi-service and multi-staff appointments, conflict detection, RFC 5545 recurring schedules, IANA timezones and DST. Online and walk-in bookings share one conflict model, so staff cannot be double-booked.

Designed payments on a PCI DSS SAQ-A model: no card data on our servers, merchant onboarding through connected accounts, three levels of duplicate-payment protection, signed webhooks, and safe refund rollback when the payment provider fails.

Autopilot Videos (autopilotvideos.com): AI short-form video platform Built a pipeline that turns news headlines, topics or any URL into narrated YouTube Shorts: LLM scripting with Gemini and Claude, voiceover through a pluggable TTS layer (ElevenLabs, OpenAI, Edge TTS, Windows SAPI, self- hosted Piper) and Remotion/FFmpeg rendering.

Publishes on a schedule to creator channels through Google OAuth and the YouTube Data API, with KMS-encrypted tokens; web (Next.js), mobile (Expo) and Express/PostgreSQL API on AWS EC2 and S3. Senior Software Engineer, BlackLine Dec 2024 – Sep 2025 Owned core components of a high-volume financial data pipeline processing invoices, account data and statements for enterprise customers.

Led design and implementation of batch processing and XML transformation workflows in Symfony and MySQL, improving throughput and reliability.

Moved stage-to-stage processing onto AWS SQS so each stage scales and fails independently; ran design reviews on service boundaries, event contracts and domain models, and worked with security and platform teams to fix application and dependency vulnerabilities found in automated and manual audits. Lead Software Engineer, Open Financial Technologies Jan 2023 – Apr 2024 Cut response times on critical production APIs (hundreds of thousands of requests per day) by 20x to 50x. The cause was architectural (controllers with 20 to 30 injected dependencies); refactored along SOLID lines and verified with APM p95/p99 data and load tests.

Designed and delivered a NestJS identity and authentication microservice used by multiple internal platforms, and owned its API contract and integration guide for consuming teams. Led a team of 5 engineers (sprint planning, code reviews, releases, Laravel upgrades); gathered requirements directly from HDFC Bank and delivered their business banking admin platform to production under bank security and compliance requirements.

Lead Architect, Spenmo Sep 2020 – Nov 2022

Architected a multi-currency, multi-country PayIn and Payout system for partners at this YC-backed fintech. Led the Cards engineering team (3 developers) with end-to-end ownership of architecture, delivery and production stability; delivered self-serve virtual and physical card lifecycle management. Owned card and wallet provider integrations (MatchMove, Rapyd): APIs, webhooks and reconciliation. Worked with Product, Operations and Compliance to turn regulatory requirements into system designs; added centralised logging and real-time alerting, reducing incident response time. Web Architect, Unocoin Technologies Pvt Ltd Jan 2017 – Aug 2020 Led modernisation of a cryptocurrency exchange: migrated a legacy PHP application to Laravel with standardised REST APIs, redesigned the MySQL schema and integrated Firebase for real-time data. Re-architected the platform for multi-country operations (currencies, languages, KYC rules, time zones) and built a configurable KYC system that added country-specific documents without app releases. Designed AWS infrastructure (VPC, EC2, Auto Scaling, caching, IAM) and moved heavy request work onto SQS queues to absorb traffic spikes during market volatility. Led a team of 7; built a unified notification service and multi-region RBAC, and ran CI/CD (Jenkins, CodeDeploy). Software Engineer, HolidayIQ.com Nov 2014 – Jan 2017 Designed Solr schemas and APIs for hotel, blog and geo-spatial search, and a Solr-based system that flagged plagiarised reviews and suspicious review activity. Built hotel ranking algorithms over user ratings for thousands of hotels, and Google Vision API image tagging for landmark detection and moderation.

Earlier Roles Oct 2010 – Nov 2014

Assistant Manager, Technology, ABC Consultants (built LinkedIn application parsing that drove 30%+ of monthly sign- ups); Senior Software Engineer, BrickWin Services; PHP Developer, Tanzanite Infotech, SoftElixir. EDUCATION

Master of Computer Applications (MCA), IGNOU 2010

B.Sc. (Honours), St. Xavier's College, Ranchi (Ranchi University) 2005

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