Senior C#/.NET Developer, Market Data Platform, Brazil
Confirmed on the employer's own hiring board on Nov 13, 2026. First seen by Alion on Nov 13, 2026. CI&T scores A on the Alion truth index.
Responsibilities
Build the .NET client for the new services from gRPC .proto contracts.
Re-implement the existing .NET wrapper so its public interface stays the same while calls go to gRPC and Arrow Flight instead of OneTick.
Convert Arrow record batches into the .NET types applications use today, efficiently and without precision loss.
Write tests that compare results from the old and new backends for the same calls.
Required
6+ years of C# and modern .NET (6 or later).
Production experience with gRPC in .NET (Grpc.Net.Client, protobuf code generation, streaming calls).
Hands-on use of Apache Arrow in .NET (Apache.Arrow package) or another columnar data format.
Strong handling of high-volume data: memory allocation, Span/Memory, streaming, async.
Care with timestamp precision, time zones and numeric types.
Nice to have
Arrow Flight in any language.
kdb+ C# client experience (csharpkdb, qSharp) or basic q.
Prior work wrapping a market data or tick database API (OneTick, kdb+, Bloomberg, Refinitiv).
Background and ways of working
Finance background (preferred, not required)
Market data work at a hedge fund, bank, broker or trading technology vendor.
Familiarity with trades, quotes, order books, symbology, corporate actions and exchange calendars.
Understanding of the difference between exchange, vendor and capture timestamps, and why it matters.
Any of: equities, options, futures, FX or fixed income data.
Also expected
Fluent written and spoken English; comfortable working directly with client engineers.
Writes tests and works in Git-based code review.
Linux comfort; CI/CD and containers are a plus.
Able to overlap at least 4 hours a day with US Eastern time.