Software Engineer (Indexer Focus) - Shielded
Shielded Technologies builds privacy-enhancing blockchain infrastructure and is the core technology partner for Midnight Network.
About Shielded Technologies
Shielded Technologies is a spinout of Input Output whose engineers and researchers build the Midnight protocol, zero-knowledge cryptography, and privacy-preserving blockchain infrastructure.
Skills
About the Role
You will design, build, and operate the components of the Midnight Indexer in Rust, including the chain indexer, wallet indexer, SPO indexer, and GraphQL API. You will build and maintain the data pipeline that fetches blocks and transactions from the Midnight node via subxt, handling finalised-block tracking, gap backfilling, and continuous real-time indexing. You will design efficient schemas and queries across PostgreSQL and SQLite, keeping latency and throughput healthy as the chain grows. You will evolve the GraphQL API with queries, mutations, and real-time subscriptions over WebSockets, with care for the wallet model and correct handling of shielded data. You will write and maintain unit, integration, and end-to-end tests, treating reliability and correctness as first-class concerns. You will own operational quality for the service, including observability, containerised deployment with Docker, and incident response. You will participate in code reviews and technical design discussions, collaborating closely with the node, ledger, wallet, and security teams, and contributing to those components as you ramp up. You will keep current with developments in Rust and blockchain technology and apply them to improve the platform.
Requirements
- At least 3 years of experience in software development, with at least 2 years in Rust
- Strong, idiomatic Rust, including async/await (tokio) and a solid grasp of concurrency
- Backend and data-systems experience building and operating high-performance services or data pipelines in production
- Practical experience with PostgreSQL and/or SQLite, including schema design and query optimisation
- Experience designing and evolving service APIs; GraphQL experience is a big plus
- Strong understanding of computer science fundamentals, including data structures, algorithms, and concurrency
- Comfortable with rigorous testing, code review, and clear technical communication
- Experience working remotely and collaborating across different time zones
- Experience working in scale-ups
- Experience with blockchain technology is a plus
- Valued: Substrate/Polkadot ecosystem experience, especially subxt
- Valued: blockchain core concepts such as consensus mechanisms, cryptography, and transaction/state models
- Valued: applied cryptography or zero-knowledge knowledge
- Valued: WASM experience compiling Rust to WebAssembly
- Valued: Cardano / partner chains context
Responsibilities
- Design, build, and operate the Indexer's components in Rust, including the chain indexer, wallet indexer, SPO indexer, and GraphQL API
- Build and maintain the data pipeline that fetches blocks and transactions from the Midnight node via subxt, handling finalised-block tracking, gap backfilling, and continuous real-time indexing
- Design efficient schemas and queries across PostgreSQL and SQLite, keeping latency and throughput healthy as the chain grows
- Evolve the GraphQL API with queries, mutations, and real-time subscriptions over WebSockets
- Write and maintain unit, integration, and end-to-end tests
- Own operational quality for the service, including observability, containerised deployment with Docker, and incident response
- Participate in code reviews and technical design discussions and collaborate with the node, ledger, wallet, and security teams
- Keep current with developments in Rust and blockchain technology and apply them to improve the platform
