Stirling-PDF vs Rivet
Side-by-side trajectory, velocity, and editorial themes.
Stirling-PDF deepens real signing and lays MCP groundwork on a fast V2 cadence
Stirling-PDF is in a heavy release cadence on its V2 line, alternating substantive minors with rapid hotfixes. The last month shipped desktop hardware-token signing (PKCS#11/smart-card and OS cert stores), a work-in-progress MCP page, JDK 25 enforcement, and large merge-memory improvements, punctuated by Postgres and desktop-signing hotfixes.
Two threads stand out: deepening real document signing (hardware tokens, shared signing, cert-store integration) and laying agent-facing groundwork via an MCP page and automation-oriented backend work. The team is also steadily reworking the V2 file-management UI that users found clunky. This is a self-hosted PDF tool maturing toward serious signing and automation use.
Expect the MCP page to move from WIP toward a usable agent interface, and the signing feature set to broaden beyond desktop-only.
Rivet pivots from actor backend to a coding-agent OS, and is building the ecosystem to match.
Rivet began as an actor and serverless backend platform — RivetKit, Rivet Actors, Rivet Compute — and has spent the last month reorienting around agentOS, a WebAssembly-based Linux environment for running coding agents without a heavy sandbox. The June and July releases show both threads running in parallel: native language SDKs (Rust, Effect) for Actors, and a fast-maturing agentOS that now has its own package registry.
The center of gravity is shifting from hosting stateful actors to being the runtime coding agents execute inside. agentOS went from a v0.2 sandbox alternative to shipping a package registry and a sub-millisecond package manager in under two weeks, a sign Rivet wants to own the developer surface around agent execution, not just the compute underneath it.
Expect agentOS to keep accreting ecosystem pieces — more registry content and tighter orchestration — while the Actors SDKs settle toward maintenance. A likely next move is deeper coupling between agentOS and Rivet Compute so agents run on Rivet's own cloud.
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