Backend Engineer

About the role
We're building a cybersecurity SaaS product with LLM-powered features. We're looking for a Senior Go engineer on a part-time basis with hourly pay, who will own backend features end to end, from API design to production. We'll share the company name after the intro call.

Format
- Part-time, hourly pay
- Fully remote
- Workload is agreed on the intro call

What you'll do
- Build new features and extend existing functionality, including LLM-based features
- Integrate the platform with third-party services
- Work with AWS infrastructure (EC2, S3 and other services)
- Review the existing codebase, suggest improvements, fix bugs and refactor

First 90 days: onboarding and getting to know the backend code, improvement proposals, bug fixes, refactoring and smaller features.

Tech stack
- Go, Labstack Echo, sqlx
- REST, Swagger / OpenAPI
- PostgreSQL
- AWS: EC2, S3, SES; AWS Bedrock for LLM features
- OpenSearch for observability
- GitHub Actions
- Monolith; background jobs run inside the backend; in-memory caching in Go

Requirements
- 4+ years of commercial backend development, including 3+ years of production experience with Go
- Advanced Go: idiomatic code, concurrency (goroutines, channels, context), error handling, testing and profiling
- Designing and documenting REST APIs (Swagger / OpenAPI) for multi-tenant SaaS, including OAuth 2.0 authorization
- Strong PostgreSQL: schema design, migrations, complex hand-written SQL without an ORM (joins, subqueries, aggregations, window functions, CTEs), query optimization (indexes, EXPLAIN)
- Building fault-tolerant integrations with external services: third-party APIs, webhooks, push/pull
- Hands-on experience with AWS as a developer: EC2, S3, SES
- Observability: logging, metrics, tracing
- Owning a feature end to end: self-review, clear API contracts for the frontend, deploying to the dev environment and testing your work before handing it over
- Secure coding: OWASP API Top 10, secrets management, handling personal data in line with GDPR
- English B1 (Intermediate) or higher

Working with AI
- You use AI daily as an assistant for refactoring, testing and debugging, while writing your own code
- You can critically review AI-generated code for bugs, security issues and design flaws
- You understand how LLMs work: prompting, common failure modes, evaluating output quality
- You've integrated LLMs into Go services: structured output (JSON, tool calling), error and timeout handling, retries, rate limits, cost and latency control

Nice to have
- SSO (OAuth / OIDC), SCIM, Microsoft Graph / Entra ID
- AWS SDK for Go
- Message brokers (RabbitMQ, Kafka)
- Integration testing
- Server-side PDF report generation; i18n in APIs
- Background in cybersecurity; understanding of cryptography (hashing, symmetric and asymmetric encryption)
- Shipping LLM-based features to production
- AI agents and tool calling (including MCP), RAG with embeddings and vector search
- LLM security: prompt injection, data leakage, OWASP Top 10 for LLM Applications

Hiring process
1. Intro call
2. Technical interview
3. Final interview and offer