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30th October 2026Critter Stack in Review: October 12th to 30thThree weeks, 72 tagged releases, and 57 pull requests from 18 people outside JasperFx. The big themes were not losing messages, with a durable inbox and outbox hardening pass that closed a dozen community-reported ways a message could go missing; performance, from SQL Server index seeks to a thread pool thread the run command was quietly eating; shutting down cleanly; an async daemon that heals itself; and multi-tenancy at a scale we'd never tested before. Plus Marten's hard stream delete, Aspire parity in Wolverine, NServiceBus XML interop, and the upgrade notes you should read first.
12th October 2026Critter Stack Week in Review: October 5th to 12thBobcat went from 0.31 to 0.50 and dropped its Gherkin lane for a projected-only model, WolverineFx.Bobcat shipped, and the whole Event Modeling to specs to scaffolding workflow got a tutorial ahead of tomorrow's live stream. Nineteen pull requests from fourteen people outside JasperFx, headlined by a NATS JetStream hardening pass and a 66 minute leader election brought down to seconds. Plus SQL Server ordered envelope ids, Marten's FetchForWriting consistency fixes, and the LINQ projection surface working under Native AOT.
5th October 2026Our Busiest Week Ever: The Critter Stack from September 28th to October 5thForty releases, 267 merged pull requests, and 38 of those from eleven people outside JasperFx. Native AOT went from aspirational to measured in CI across Marten, Wolverine, Polecat, and Fisher. Weasel picked up a Firebird provider and a pile of MySQL, Oracle, and SQLite fixes from the Quartz.NET maintainer. Wolverine's global partitioning got hardened by a user running it hard in a real cluster. And Polecat and Fisher kept pace with Marten the whole way.
1st October 2026Fisher: A Document Database for Anywhere SQLite is a Good ChoiceFisher gets talked about as the Critter Stack's event store on SQLite, but it's also a full document database that lives in a file inside your own process. If SQLite is the right storage for your application, Fisher is a much lower ceremony way to use it than EF Core: no mapping, no migration files, schema changes that just work through Weasel, and a first class Wolverine integration.
9th September 2026Event Sourcing Quick Start with MartenLet's get up and running with event sourcing using Marten
30th August 2026Clone, docker compose up, Go: Friction-Free EF Core Integration Testing with Weasel and WolverineWeasel manages the schema for every EF Core DbContext in your application the same way it has always managed Marten's -- and its FK-aware database cleaner plus IInitialData give you a fast, repeatable reset between tests. Clean clone to green test suite with no migration chain to run.28th August 2026Meet Weasel: The Schema Engine Powering the Whole Critter StackWeasel is the least-famous member of the Critter Stack, but it's the schema-management and SQL-generation engine underneath Marten and Polecat -- and it just became a shared, dialect-neutral runtime for both event stores.
27th August 2026Change Documents Without Loading Them: The Patching API in Marten, Polecat, and FisherThe Critter Stack's Patching API lets you modify persisted JSON documents in place -- no deserialize, mutate, re-serialize round trip. Here's the shared API across Marten, Polecat, and Fisher, what each database does underneath, and where the three genuinely differ.
25th August 2026NServiceBus to Wolverine using our AI SkillsThe mechanical half of an NServiceBus migration goes fine unaided. The part that goes wrong is the decision NServiceBus used to make for you -- how each endpoint listens. Here's the same question asked twice, once with the JasperFx AI Skills installed and once without.2nd August 2026A Week in the Critter Stack: Security, Preventing Data Loss, and Rolling PartitionsSeven days, twenty-two releases across Marten, Wolverine, Polecat, Weasel, and JasperFx: a PostgreSQL injection fix under sharded tenancy, two silent data-loss bugs in Wolverine, self-managing time-series partitions, and a big wave of production hardening for projection agent distribution.
20th July 2026Boring on Purpose: How the Critter Stack Keeps Getting BetterMature open-source infrastructure isn't about splashy features -- it's about compounding reliability and measured performance work. Here's how the Critter Stack keeps getting faster and more correct underneath you.24th May 2026Marten 9.0, Polecat 4.0, and Wolverine 6.0 are Live!The Critter Stack 2026 releases have landed: faster cold starts, AOT compliance, better Serverless support, and new greenfield defaults across Marten, Polecat, and Wolverine.20th May 2026Introducing the Critter Stack AI SkillsJasperFx Software's officially curated AI Skills for the Critter Stack are now available for purchase — continuously improved guidance that helps AI coding agents write idiomatic Marten, Polecat, and Wolverine code.20th August 2025Integration Testing with the Critter StackA live stream laying out the tools and approaches in the Critter Stack for automating integration testing, and the technical challenges you will run into along the way.
2nd April 2025A Quick Note about Our Plans for Marten and WolverineAs competing .NET tools move to paid licenses, Marten and Wolverine stay MIT licensed under JasperFx's open core model, with services, support plans, and CritterWatch funding the work.15th November 2023The Critter Stack at .NET 2023Jeremy's .NET 2023 talk on CQRS with Event Sourcing using Marten and Wolverine: lower code ceremony, a great local developer story, testable domain logic, and built-in diagnostics.
Critter Stack
Posts tagged Critter Stack
30th October 2026Critter Stack in Review: October 12th to 30thThree weeks, 72 tagged releases, and 57 pull requests from 18 people outside JasperFx. The big themes were not losing messages, with a durable inbox and outbox hardening pass that closed a dozen community-reported ways a message could go missing; performance, from SQL Server index seeks to a thread pool thread the run command was quietly eating; shutting down cleanly; an async daemon that heals itself; and multi-tenancy at a scale we'd never tested before. Plus Marten's hard stream delete, Aspire parity in Wolverine, NServiceBus XML interop, and the upgrade notes you should read first.12th October 2026Critter Stack Week in Review: October 5th to 12thBobcat went from 0.31 to 0.50 and dropped its Gherkin lane for a projected-only model, WolverineFx.Bobcat shipped, and the whole Event Modeling to specs to scaffolding workflow got a tutorial ahead of tomorrow's live stream. Nineteen pull requests from fourteen people outside JasperFx, headlined by a NATS JetStream hardening pass and a 66 minute leader election brought down to seconds. Plus SQL Server ordered envelope ids, Marten's FetchForWriting consistency fixes, and the LINQ projection surface working under Native AOT.5th October 2026Our Busiest Week Ever: The Critter Stack from September 28th to October 5thForty releases, 267 merged pull requests, and 38 of those from eleven people outside JasperFx. Native AOT went from aspirational to measured in CI across Marten, Wolverine, Polecat, and Fisher. Weasel picked up a Firebird provider and a pile of MySQL, Oracle, and SQLite fixes from the Quartz.NET maintainer. Wolverine's global partitioning got hardened by a user running it hard in a real cluster. And Polecat and Fisher kept pace with Marten the whole way.1st October 2026Fisher: A Document Database for Anywhere SQLite is a Good ChoiceFisher gets talked about as the Critter Stack's event store on SQLite, but it's also a full document database that lives in a file inside your own process. If SQLite is the right storage for your application, Fisher is a much lower ceremony way to use it than EF Core: no mapping, no migration files, schema changes that just work through Weasel, and a first class Wolverine integration.9th September 2026Event Sourcing Quick Start with MartenLet's get up and running with event sourcing using Marten30th August 2026Clone, docker compose up, Go: Friction-Free EF Core Integration Testing with Weasel and WolverineWeasel manages the schema for every EF Core DbContext in your application the same way it has always managed Marten's -- and its FK-aware database cleaner plus IInitialData give you a fast, repeatable reset between tests. Clean clone to green test suite with no migration chain to run.28th August 2026Meet Weasel: The Schema Engine Powering the Whole Critter StackWeasel is the least-famous member of the Critter Stack, but it's the schema-management and SQL-generation engine underneath Marten and Polecat -- and it just became a shared, dialect-neutral runtime for both event stores.27th August 2026Change Documents Without Loading Them: The Patching API in Marten, Polecat, and FisherThe Critter Stack's Patching API lets you modify persisted JSON documents in place -- no deserialize, mutate, re-serialize round trip. Here's the shared API across Marten, Polecat, and Fisher, what each database does underneath, and where the three genuinely differ.25th August 2026NServiceBus to Wolverine using our AI SkillsThe mechanical half of an NServiceBus migration goes fine unaided. The part that goes wrong is the decision NServiceBus used to make for you -- how each endpoint listens. Here's the same question asked twice, once with the JasperFx AI Skills installed and once without.2nd August 2026A Week in the Critter Stack: Security, Preventing Data Loss, and Rolling PartitionsSeven days, twenty-two releases across Marten, Wolverine, Polecat, Weasel, and JasperFx: a PostgreSQL injection fix under sharded tenancy, two silent data-loss bugs in Wolverine, self-managing time-series partitions, and a big wave of production hardening for projection agent distribution.20th July 2026Boring on Purpose: How the Critter Stack Keeps Getting BetterMature open-source infrastructure isn't about splashy features -- it's about compounding reliability and measured performance work. Here's how the Critter Stack keeps getting faster and more correct underneath you.24th May 2026Marten 9.0, Polecat 4.0, and Wolverine 6.0 are Live!The Critter Stack 2026 releases have landed: faster cold starts, AOT compliance, better Serverless support, and new greenfield defaults across Marten, Polecat, and Wolverine.20th May 2026Introducing the Critter Stack AI SkillsJasperFx Software's officially curated AI Skills for the Critter Stack are now available for purchase — continuously improved guidance that helps AI coding agents write idiomatic Marten, Polecat, and Wolverine code.20th August 2025Integration Testing with the Critter StackA live stream laying out the tools and approaches in the Critter Stack for automating integration testing, and the technical challenges you will run into along the way.2nd April 2025A Quick Note about Our Plans for Marten and WolverineAs competing .NET tools move to paid licenses, Marten and Wolverine stay MIT licensed under JasperFx's open core model, with services, support plans, and CritterWatch funding the work.15th November 2023The Critter Stack at .NET 2023Jeremy's .NET 2023 talk on CQRS with Event Sourcing using Marten and Wolverine: lower code ceremony, a great local developer story, testable domain logic, and built-in diagnostics.