In January, DataStax contracted with Sembit to build out a .NET / C# SDK for Astra DB. The goal was to increase adoption of Astra, its serverless Cassandra‑as‑a‑service platform, among .NET teams. We needed to produce a production‑ready, MIT‑licensed SDK that would make Astra’s new Data API feel fluent for C# devs. Over the six‑month engagement, our three person team built, documented, and shipped the astra‑db‑csharp repository, now live on GitHub and already powering customer workloads.

From the outset, the project posed a couple challenges. First, we needed to keep to our timeline - this is always a priority, but in this case we wanted to keep lock-step with the other SDK teams. Second, the underlying Data API was still evolving, so our design had to absorb potential breaking changes without derailing the release schedule. We were able to keep to our schedule, absorb several changes as we went, and even had time to work with the DataStax technical writer to create and help publish complete SDK docs.

We tackled the brief in four phases that blended agile sprints with transparent, open‑source workflows. January was devoted to discovery, where we aligned on developer‑experience goals such as a fluent connection builder, fault‑tolerant use of `HttpClientFactory`, and pluggable JSON serialization. February and March focused on an alpha that proved the complete CRUD path end‑to‑end against Astra’s public sandbox and covered the vast majority of the Data API’s surface. In April and May, we hardened the codebase—adding XML comments, a DocFX site, GitHub Actions CI, and unit‑test coverage that now hovers around ninety‑two percent—while engaging community testers for feedback. June marked general availability: we cut v1.0.0, signed the NuGet packages, and published them under semantic versioning.

“They delivered on time, communicated proactively, and were a great partner to work with.”
— Greg Petrossian, Strategic Partnerships, DataStax
(5‑star Clutch review, project January–June 2025)

Read more from the DataStax review of our work here on Clutch.

The business payoff here is in increased adoption. By offering first‑class .NET support, DataStax removed a major barrier for thousands of enterprise C# teams. Sample applications now connect securely to Astra DB in under thirty lines of code, freeing developers to prototype rather than wrestle with raw REST calls. The open‑governance model signals that contributions and issue tracking happen in the open, reinforcing DataStax’s long‑standing commitment to transparent, community‑driven software.

The SDK is released under the Apache‑2.0 license and ready for immediate use:

GitHub: https://github.com/datastax/astra-db-csharp

NuGet: dotnet add package DataStax.AstraDB.DataApi

If your organization needs to accelerate a similar platform rollout - or you want bespoke integrations that extend Astra DB into your existing stack - get in touch with Sembit. We help products reach more developers, faster, with the reliability enterprise customers expect.