* Salário: R$ 2.000 a R$ 5.000 por mês (estimado)
* O valor exibido é uma estimativa calculada com base em dados públicos e referências do mercado. Não garantimos que este seja o salário oferecido para esta vaga específica.
Área: Outros
Nível: Junior
Job Title: Senior / Staff Back-End Developer (C# / .NET + SQL)
Location: Remote
Company: Confidential
About Us: A technology company at heart, with world class robotics designed, built, and operated in house, disrupting the direct mail industry with a brand new advertising medium. Paired with an advanced direct mail advertising platform (SaaS), we integrate into the broader omni-channel advertising ecosystem. We enable businesses to connect meaningfully with
customers through personalized, robotically handwritten mail that vastly outperforms conventional printed pieces. Our mission is to make direct mail advertising as effortless and impactful as digital advertising.
Position Overview: We’re seeking a Senior/Staff Back-End Developer with mastery in C#/.NET and SQL to architect and build the robust systems that power our platform. You’ll work on complex data-driven applications, high-scale services, and performance-critical pipelines. You’ll also play a key role in shaping product direction, helping us deliver features fast while maintaining reliability and scalability.
Key Responsibilities:
● Architect, build, and maintain APIs, services, and back-end systems in C#/.NET.
● Write advanced SQL queries and design efficient schemas for high-volume transactional and analytical workloads.
● Build and maintain data ingestion pipelines and ETL processes, ensuring data accuracy, integrity, and performance.
● Integrate with external systems via APIs, handling authentication, rate limits, retries, and data transformations.
● Identify performance bottlenecks and optimize database interactions for scalability.
● Debug and extend existing systems, quickly understanding complex codebases.
● Collaborate with product and front-end engineers to deliver end-to-end features.
● Contribute to technical design, best practices, and mentoring within the engineering team.
Qualifications:
● 7+ years professional experience, with at least 4+ years deep expertise in C#/.NET (Core preferred) building scalable back-end systems.
● Deep SQL knowledge (query optimization, indexing, performance tuning, schema design).
● Strong experience with data ingestion pipelines, ETL, and large-scale data workflows.
● Experience integrating external APIs and third-party systems.
● Solid understanding of good programming practices and modern software architecture principles:
○ Onion Architecture / Clean Architecture
○ Bounded Contexts
○ Domain-Driven Design (DDD)
● Experience with distributed systems, messaging, or cloud infrastructure (Azure/AWS) a strong plus.
● Track record of delivering features in high-scale, data-intensive environments.
● Hands-on experience with NServiceBus or similar service bus / messaging frameworks (MassTransit, RabbitMQ, Kafka, Azure Service Bus, etc.).
● Proficiency with unit testing, integration testing, and smoke testing, using frameworks such as xUnit, NUnit, Moq, or NSubstitute.
● Hands-on experience deploying and managing applications in Azure Cloud (or AWS).
● Solid understanding of GitFlow branching strategy and experience with CI/CD pipelines using GitHub Actions.
● Non-technical:
○ Strong product sense, able to see the big picture.
○ Comfortable with ambiguity in requirements — driving clarity and execution.
○ Quick learner and debugger, able to dive into unfamiliar systems with confidence.
○ Motivated to be part of a fast-moving, high-performance team, owning big chunks of the product.
○ Advanced/Fluent English
What you can expect at LettrLabs:
● Industry competitive salary
● Open and encouraged PTO policy
● 9 company paid holidays
Why Join Us?
You’ll be part of a forward-thinking team dedicated to transforming direct mail marketing. We offer a collaborative work environment, opportunities for professional development, and the chance to make a significant impact on our growth.