Core SDK Development

4 posts · Apr 2021 – Oct 2026

What this trail covers

The Temporal Rust SDK has reached version 1.0.0, demonstrating its production readiness and portability by successfully running on an ESP32-S3 microcontroller. This achievement validates the SDK's ability to operate in resource-constrained environments and highlights the robustness of its core Durable Execution capabilities, including TLS authentication, task polling, and activity heartbeating. The project involved minimal, targeted compatibility patches for the ESP-IDF environment, showcasing the SDK's adaptability and the effectiveness of the Rust Core SDK's design. This success further solidifies the Rust SDK's role as a foundational component for Temporal's cross-language SDK strategy.

All Temporal trails

Oct 2026I put Temporal's Rust SDK 1.0 on a conference badgeThis post details the successful porting of the Temporal Rust SDK 1.0 to an ESP32-S3 microcontroller, demonstrating its capability to function as a Temporal Worker in a highly resource-constrained embedded environment. Key technical contributions include: compiling the Rust SDK with minimal compatibility patches (four specific gates for Tokio, portable-atomic, hostname/platform discovery, and float deserialization issues), integrating TLS and API key authentication to Temporal Cloud, implementing Activity polling and heartbeating on the device, and designing a game workflow where the badges act as Activity Workers. The post also highlights the runtime constraints imposed by Tokio on embedded systems and the strategies used to mitigate them, as well as the challenges and solutions encountered in making the embedded system robust for a conference booth demo, including sleep/wake behavior and workflow versioning.
Sep 2026Build durable applications in Rust: the Temporal Rust SDK is now generally availableThis post announces the general availability of the Temporal Rust SDK. It details how Rust developers can write Workflows and Activities using familiar Rust constructs like structs and async functions. Procedural macros are used to define Workflows and Activities, with typed method references ensuring type safety. The SDK integrates with Tokio for worker execution and provides deterministic alternatives to standard async primitives (e.g., ctx.timer, deterministic select!) to maintain Workflow determinism. It also highlights the runtime nondeterminism detector and the testing features, including WorkflowReplayer for replaying recorded histories against new code.
May 2025Improving our Java SDK with Codex by OpenAIThis post details how Codex by OpenAI was used to improve the Java SDK, including fixing bugs, implementing missing features (like counting workflow executions using search attributes), and adding end-to-end tests. It also discusses the creation of AGENTS.md files to guide AI agents in understanding and interacting with codebases, and mentions that Temporal is used to power Codex's own reliability and scalability.
Apr 2021Why Rust powers Temporal’s new Core SDKThis post details the challenges of Temporal's client-side libraries, including complex event reconciliation, the need to support multiple languages idiomatically, and the requirement for extreme reliability. It explains the algorithm a Temporal worker follows and highlights the duplication of complex state machine logic across existing SDKs. The post introduces the concept of a shared Core SDK and justifies the choice of Rust for its performance, safety, and ability to compile to WASM, facilitating integration with other languages and potentially enabling out-of-process communication via Protobufs.
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