Agoda Services Co. Ltd.
Software Engineer (Backend) • Bangkok, Thailand
Worked on backend systems for Agoda Activities, including rate limiting, caching, observability, and test tooling.
Backend Engineer • Distributed Systems • Cryptography
"An abstraction is one thing that represents several real things equally well."
— Edsger W. Dijkstra
I’m Ratul Antik Das, a backend-focused software engineer with 9+ years of experience across travel, fintech, blockchain, and mobile platforms. I enjoy working on distributed systems, scalable APIs, performance tuning, and security-sensitive engineering problems.
Recent focus
Backend work at Agoda Activities across rate limiting, caching, observability, and test tooling.
Strength
Debugging production issues, improving performance, and making backend behavior easier to understand.
Background
Cryptography, blockchain, mobile SDK security, and payment-related systems.
Experience
Kona Software Lab Ltd.
Senior Software Engineer • Dhaka, Bangladesh
Built backend systems, SDK capabilities, and cryptography-related features across fintech, digital wallets, blockchain products, and mobile banking applications.
Selected Work
Dynamic Rate Limiter
Agoda- Built an outbound rate-limiting layer for supplier APIs to protect critical booking flows while adapting non-booking traffic limits in real time.
- Balanced system safety and throughput by preserving minimum safeguards for business-critical endpoints during traffic spikes.
Activity Supply Supplier Integration
Agoda- Implemented core supplier integrations for the Activities platform and improved response performance through more precise cache TTL strategies.
- Resolved A/B testing data inconsistencies by introducing experiment-aware cache keys.
- Designed a non-instant cancellation flow that increased inventory and bookings by more than 20%.
- Reduced supplier incident detection time by more than 40% through clearer Grafana dashboards and alerting.
- Used GPT-assisted prompt workflows to generate supplier-specific POJOs and converters, cutting repetitive implementation work.
- Set up a webhook testing environment to validate payload formats before production rollout.
Functional Test Framework
Agoda- Built a functional testing framework using recorded supplier and dependent-service response data.
- Used mocked downstream responses to validate API behavior before deployment.
- Integrated the framework into GitLab CI/CD to catch API regressions before deployment.
Cryptrade (P2P Crypto Exchange)
Kona Software Lab- Built a server-side custodial wallet system using hierarchical deterministic key generation.
- Integrated Bitcoin and Ethereum single-signature and multisignature transaction flows, validated through crypto testnet deployments.
E-Voting Platform
Kona Software Lab- Developed chaincode for decentralized voting workflows, including event creation, vote casting, and result finalization.
- Built backend APIs with complex data views and caching strategies to improve response time.
- Delivered full-stack features including NICE identity verification, event updates, and automated result publication.
Real Estate DApp
Kona Software Lab- Built a proof-of-concept smart contract to handle fund transfers to stakeholders in a real estate workflow.
Transaction Finality R&D
Kona Software Lab- Co-developed a checkpointing algorithm for an in-house blockchain platform to reduce chain reorganization risk and improve transaction finality.
- Experimented with OCSP and CRL strategies for certificate revocation across network nodes.
- Co-authored an IEEE conference paper on the finality protocol.
Nagad (Mobile Financial Service)
Kona Software Lab- Integrated an in-house white-box cryptography library into the KonaPay SDK to strengthen the security foundation of the Nagad mobile app.
- Enabled secure client-side storage and cryptographic operations for a product serving more than 2 million active users.
White-Box Cryptography Module
Kona Software Lab- Built an in-house white-box AES module by translating cryptographic techniques from academic research into production-oriented code.
- Designed the module to work both as a standalone library and as an embedded SDK component for iOS and Android apps.
NexusPay (Banking Application)
Kona Software Lab- Built mobile UI features and core application capabilities for the Android and iOS banking apps.
- Implemented an internal QR parsing library for TLV data in EMV-compliant merchant QR codes.
KonaPay (Wallet SDK)
Kona Software Lab- Improved SDK security posture by auditing vulnerabilities and aligning implementations with OWASP guidance.
Get In Touch
I’m open to backend engineering roles and thoughtful technical conversations. If you’re building systems that need scale, reliability, or security-sensitive design, I’d be glad to connect.
Phone: (+88) 01823382033