Senior Backend Engineer — Platform & Scale for Elfster

About the Company

Elfster is the free way for friends, families, and coworkers to organize a Secret Santa, run any gift exchange, and build wishlists everyone can actually shop from. Since 2000, more than 47 million gift givers across 50+ countries have used the platform to draw names, manage exchanges, and shop for the people they care about.

What makes engineering here interesting is the shape of the traffic. Elfster is one of the most seasonal consumer platforms you will work on: a large share of the year’s activity compresses into the weeks between early November and late December, when millions of people create exchanges, draw names, post wishlist items, and get notified — often within the same few hours on the same few days. The system has to stay quiet and cost-efficient for most of the year, then absorb an order-of-magnitude jump in RPS on a schedule everyone can see coming. Designing for that is not a background concern here; it is the central engineering problem.

We are a small, senior team. That means real ownership, short paths from idea to production, and no layers between you and the decisions that matter.

About the Role

We are hiring a Senior Backend Engineer to bring deeper platform and scalability depth to our backend group.

This is a peer role alongside our existing backend engineers who already carry infrastructure scope — not a layer above them. They own services end to end, ship features, and run what they build in AWS. You will do the same. The difference is the depth you bring to the platform layer underneath all of it: the data stores, the messaging backbone, the analytics pipeline, and the capacity thinking that determines whether peak season is uneventful or not.

Concretely, you will be the engineer the team leans on when the question is “will this hold in December?” — and the one who turns that answer into architecture, load models, runbooks, and instrumentation rather than a hunch. You will also make that depth transferable: design docs others can review, patterns others can reuse, and dashboards others can read at 2am.

What You’ll Do

• Design and build scalable APIs that serve a consumer platform with a highly seasonal traffic profile — owning the service contract, its performance characteristics, and its failure behavior.
• Architect for peak. Model expected RPS and concurrency for the holiday season, size and shape systems against it, and validate through load and stress testing well ahead of November — while keeping the off-season footprint efficient.
• Own the data layer as it evolves. Make deliberate choices between relational and non-relational stores, design schemas and access patterns that scale, and evolve them safely as features grow.
• Build and scale asynchronous infrastructure. Message queues, event and bus architectures, and the decoupling that lets the platform shed load gracefully instead of failing loudly.
• Deepen our analytics platform. Work with our OLAP/warehouse layer (Amazon Redshift) so product, growth, and marketing get reliable data as the underlying models change.
• Deploy and operate services in AWS from scratch — provisioning, networking, infrastructure as code, CI/CD, and the operational scaffolding that comes with a service being real.
• Make the system observable. Meaningful metrics, structured logs, traces, SLOs, and alerts that fire on user visible problems rather than on noise.
• Take end-to-end ownership. From design through development, rollout, on-call, incident response, postmortems, and the unglamorous maintenance that makes operational excellence real rather than aspirational.
• Write things down. Design docs, architecture decision records, runbooks, and API documentation that let a smallteam move fast without holding the system in one person’s head.

What We’re Looking For

Backend engineering depth

• Substantial experience building backend services and scalable APIs in C#/.NET — or comparable depth in another backend ecosystem with a genuine willingness to work in ours.
• A track record of services that stayed up and stayed fast as traffic and feature scope grew.

Data and messaging

• In-depth working knowledge of relational databases: modeling, indexing, query performance, migrations under load, replication and read scaling.
• Practical experience with non-relational stores, and clear judgment about when they are the right tool.
• Real experience with message queues and bus/event-driven architectures — delivery semantics, idempotency, ordering, retries, dead-letter handling, and backpressure.
• Hands-on experience with an OLAP/warehouse layer; Amazon Redshift specifically is a strong plus — including how to evolve it as upstream models change without breaking downstream consumers.

Scalability, resiliency, and observability

• Fluency with scalability principles: caching strategies, connection and resource pooling, horizontal scaling, partitioning, and the trade-offs between them.
• Resiliency as a design habit — timeouts, retries with backoff, circuit breakers, graceful degradation, and blast- radius containment.
• Observability treated as a first-class deliverable, not something bolted on during an incident.

Cloud and operations

• Meaningful AWS experience, including standing up and deploying services from scratch rather than inheriting them.
• Comfort owning production: on-call participation, incident response, and driving durable fixes out of postmortems.

How you work

• You believe in documentation and produce it as part of the work, not after being asked.
• You take end-to-end ownership — a feature is yours through maintenance, not through merge.
• You design with peak traffic and RPS in mind by default, so systems hold during the holiday surge and stay economical the rest of the year.
• You collaborate well on a small team where backend, frontend, and QA sit close together and everyone’s decisions are visible.

Nice to Have

• Experience with consumer platforms that have pronounced seasonal or event-driven traffic spikes.
• Load and stress testing practice — building the harness, not just reading the report.
• Cost-aware architecture: right-sizing, autoscaling policy, and reserved/spot strategy in AWS.
• Experience with high-volume transactional messaging or notification infrastructure (email, push).
• Security-conscious design and familiarity with the operational side of consumer data protection

How This Role Sits in the Team

Our backend engineers are generalists with infrastructure scope: they build features, own their services in AWS, and take their turn in the on-call rotation. This role is deliberately a peer to that — the same ownership, the same rotation, the same product work.

What we are adding is depth. When a feature needs a new queue topology, when Redshift models must change without breaking reporting, when a schema change has to ship under load, or when we need a real capacity plan for November instead of a guess, this is the engineer who leads that thinking and brings the rest of the team along. If you want scope that is technically deep and operationally real without leaving hands-on engineering, this is that role.

Why Elfster

• A product people are happy to use. Elfster shows up in people’s lives around gifts, family, and celebration — not in their spreadsheets.
• Scale with a small team. Tens of millions of users, and a team small enough that your architectural decisions are visible in production within weeks.
• A rare engineering problem. Extreme seasonality forces you to be good at capacity planning, elasticity, and cost — skills most consumer backends never have to develop.
• Real ownership. You will not be handed a narrow slice of someone else’s system.

We Offer

• We welcome new ideas and allow you to make an immediate impact on the team
• Flexible Paid time off (PTO for any reason, including sick days (no specified limits) and flexible work schedule.
• Personal laptop.
• Health and wellness package.
• Fully remote.

As this is an English-speaking role, we kindly ask that all applications be submitted with a CV in English.