This week the CNCF Spin project released Spin 3.4, which includes several notable enhancements to Spin.
In this blog post, we'll dive into a few exciting features of this release, which center on enabling HTTP/2 for outgoing requests, pooling Postgres connections, broadening the range of PostgreSQL data types, and an added schema directive for spin.toml to enable validation and code completion.
HTTP/2 for outgoing requests
Spin now supports making outgoing HTTP/2 requests. Until now, Spin applications could only make outbound calls over HTTP/1.1. With this release, developers can seamlessly interact with APIs and services that require or benefit from HTTP/2, such as gRPC-based back ends. This unlocks a whole new set of integration scenarios for Spin apps — whether you're connecting to microservices, cloud APIs, or high-throughput data pipelines.
HTTP/2 support means better performance and efficiency: multiplexed requests on a single connection, lower latency, and improved network utilization. For developers, the upgrade is transparent — just use the existing outbound HTTP interface in Spin, and Spin will negotiate HTTP/2 when the server supports it. No configuration changes are needed. This step makes Spin an even more capable platform for building Wasm-powered, event-driven applications that need to talk to the broader web at scale.
In a follow-up post, we will be digging into the new wasi-grpc crate, which enables gRPC clients to operate in Spin components.
Pooling Postgres connections
Spin now pools PostgreSQL connections, making database access faster and more efficient. Instead of opening a new connection for every query, Spin apps reuse existing connections behind the scenes. This means lower latency, better performance under load, and smoother scaling for data-driven applications — all without any extra work from you.
Expanded PostgreSQL data types
Spin's PostgreSQL support just got a major boost. You can now work with UUID, JSONB, decimal (NUMERIC), range types, array types, and INTERVAL, preserving their structure in the database, and making JSON queries, range queries, and more possible right in your Spin apps. More types, more flexibility, more power.
Template manifest schema directives
Spin templates now include a schema directive in your spin.toml, enabling validation and code completion automatically in most editors. With Even Better TOML (or an equivalent) installed, you'll get clearer guidance, fewer mistakes, and a smoother experience when working with Spin manifests — no extra setup required.
A special thank you to our contributors
We would like to thank the over 85 contributors to the Spin project. Thank you to everyone in our growing community!
A special mention goes out to the maintainers of the Bytecode Alliance projects, particularly the Wasmtime project, and the developers working on WASI and the WebAssembly component model. Their work is instrumental in supporting Spin.
Stay in touch
We invite you to join our weekly project meetings, chat with us in the Spin CNCF Slack channel, and follow us on X (formerly Twitter) @spinframework.
To get started with Spin and explore the latest features, follow the Spin quickstart, which provides step-by-step instructions for installing Spin, creating your first application, and running it locally. Also head over to the Spin Hub for inspiration on what you can build.
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