Senior Software Engineer (SDE-3)

About 30 Sundays

30 Sundays is a modern holiday company helping Indians plan and book international trips with high-quality itineraries, great stays, and seamless on-trip support. Founded by IIT–IIM and ex-Apple leaders, with a core team from Flipkart, Spinny, and OYO, and backed by leading investors including Info Edge and Eximius.

We are building a consumer-first travel platform that transforms how people discover, plan, and book holidays — and we're growing fast.

Role Summary

We are looking for a Senior Software Development Engineer (SDE-3) to join our core engineering team. You will be an individual contributor owning critical systems and features end-to-end — writing production-grade code, driving technical design, and raising the engineering bar across the team.

This role is ideal for someone who is deeply hands-on, thrives on hard technical problems, and wants to build consumer internet products at scale from the ground up.

What You'll Build

Consumer Travel App Build and scale a best-in-class travel discovery and booking experience for Indian travellers, focusing on speed, usability, and personalization. Design and implement features that move beyond traditional booking interfaces and deliver a modern, intuitive holiday-planning experience.

Key Technical Areas

• Travel Discovery: Design and build engaging discovery surfaces — destination feeds, curated collections, search, and filtering.
• AI & Personalization: Implement recommendation engines and ranking systems that adapt to user preferences and browsing behaviour.
• High-Performance Platform: Architect and maintain a fast, reliable, mobile-first backend capable of supporting 20Mn+ DAUs.
• Data-Driven Product: Instrument features with analytics, run experiments (A/B tests), and iterate rapidly based on user insights.
• Internal Tooling: Build internal platforms and ops tooling that help the business operate efficiently at scale.

Key Responsibilities

• Build, maintain, and scale backend services and REST APIs for the consumer app and internal platforms.
• Design secure, high-performance server-side logic using Node.js as the primary stack.
• Own data modelling, schema migrations, and query optimization across SQL and NoSQL databases.
• Write clean, modular, well-tested backend code and maintain high standards through code reviews.
• Debug production issues, resolve performance bottlenecks, and ensure smooth deployments.
• Integrate third-party APIs, data pipelines, and background processes to support both product and internal operations.
• Collaborate with product, frontend, and internal teams to translate business requirements into robust backend solutions.
• Define backend architecture patterns and best practices that scale across the engineering team.

Technology Stack

Core Backend

• Runtime & Language: Node.js (primary), Python (secondary)
• API Layer: REST APIs, Express.js / Fastify
• Authentication: JWT, OAuth 2.0, session management

Databases

• Relational: PostgreSQL / MySQL — schema design, indexing, migrations
• NoSQL: MongoDB / Redis — caching, session storage, real-time data
• Search: Elasticsearch — for destination and itinerary discovery

Infrastructure & DevOps

• Cloud: AWS (EC2, S3, RDS, Lambda) / GCP
• Containers: Docker, Kubernetes
• CI/CD: GitHub Actions / CircleCI
• Monitoring & Observability: Datadog, Sentry, CloudWatch

Async & Integrations

• Message Queues: SQS, Bull / BullMQ
• Background Jobs: Cron-based workers, event-driven pipelines
• Third-party Integrations: Payment gateways, travel APIs, CRM and ops tools

Developer Tooling

• Version Control: Git, GitHub
• Code Quality: ESLint, Prettier, unit and integration testing (Jest / Mocha)
• CLI & Scripting: Bash, Python scripts for automation

What We're Looking For

Must Have

• 5-6 years of backend development experience (excluding internships), with a strong track record of shipping production systems.
• Deep expertise in Node.js — you've used it to build and scale real, high-traffic services.
• Strong experience designing and building REST APIs, authentication systems, and server-side architecture.
• Proficiency in both SQL and NoSQL databases — data modelling, indexing, migrations, and query optimization.
• Experience owning production systems end-to-end, including monitoring, debugging, and incident response.
• Familiarity with Git, CLI tooling, and rigorous code review practices.
• Prior experience at a consumer internet startup is strongly preferred.

Good to Have

• Working knowledge of Python for scripting, automation, or data pipelines.
• Experience with cloud platforms — AWS, GCP, or Azure.
• Exposure to background job systems, event-driven architectures, or message queues (e.g. SQS, Kafka, Bull).
• Experience building internal tooling or admin systems in addition to consumer-facing products.

Preferred Education

B.Tech / B.E. from IITs, top NITs, BITS Pilani, or equivalent strong engineering institutions. We value demonstrated ability and impact over pedigree.

Why Join 30 Sundays

• Greenfield problem space — build systems from scratch; your architecture decisions will shape millions of trips.
• Technical depth + product impact — write code that directly moves key product metrics with no layers between you and the outcome.
• Backed by top investors — Info Edge and Eximius backing with a clear path to scale.
• Travel as a perk — experience the product you build; annual travel credits included.