Originally posted on LinkedIn on 11 October 2026. The code has since moved from Codeberg to GitHub; the link is updated.

Apollo held their summit last week and everyone came home talking supergraphs. Our timing was good: in this release skilj's GraphQL endpoint can join a supergraph as an Apollo Federation v2 subgraph.

Quick refresher: skilj is an event-sourcing framework in Rust on Postgres. You define commands and events, and you get GraphQL and REST APIs, projections, snapshots and messaging bridges.

Federation v2

• Plugs into Apollo Router (2 and the 3.0 preview), Hive Router or Gateway, Cosmo, or schema stitching.
• Projections become entities, and each lookup is checked against the caller's own permissions.
• CI composes the schema with both Apollo's and Hive's composition on every build.

Commands read only what they need (Dynamic Consistency Boundaries)

• Consistency queries: a command names exactly the events its decision depends on.
• nothing(): for commands that need no history. On one hot account that took us from 110–160 to 2,500–5,000 commands/s.
• Snapshots as query items: a transfer between two accounts can decide on a snapshot of each.
• New warnings for slow reads and slow decides, with defaults taken from our benchmarks, so you find out before your users do.

Speed

• Projection catch-up is 25–50× faster.
• Fewer round trips and no connection ping per command. With 1 ms to Postgres, a single caller went from 46 to about 26 ms per command.
• Batches are written as sets, and sync projections fold a whole batch at once.
• A small Kafka producer setting (linger.ms=0) takes outbound from about 165 to about 2,000 events/s.

Safety

• Database epochs: after a failover or restore, a stale position is refused instead of quietly skipping events.
• Per-message idempotency keys, so NATS and AMQP redeliveries are no longer lost.
• Command dry-runs: see what a command would decide without persisting anything.
• A conformance suite that checks GraphQL and REST give the same answers.

Plus a pile of fixes, new benchmarks and deployment guidance in docs/performance.md.

We're still at 0.0.x, so some things broke: nextCursor on GET /v1/events is now an opaque string, submit_command takes snapshot states, and a few signatures changed in skilj-graphql and skilj-bridge. Read the CHANGELOG before you upgrade.

All 15 crates are on crates.io, and the code is at gklijs/SkilJ.

Photo: Where the roads meet the sea, by me.