--- title: Introducing mirrord Chaos Testing | daily.dev description: MetalBear has launched mirrord Chaos Testing, a feature that lets developers deliberately inject latency or connection failures into their own service's... canonical: https://daily.dev/posts/introducing-mirrord-chaos-testing-emvolloz5 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Introducing mirrord Chaos Testing | daily.dev og:description: MetalBear has launched mirrord Chaos Testing, a feature that lets developers deliberately inject latency or connection failures into their own service's... og:url: https://daily.dev/posts/introducing-mirrord-chaos-testing-emvolloz5 og:image: https://api.daily.dev/og/posts/emVOlloZ5.png og:image:alt: Introducing mirrord Chaos Testing og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Introducing mirrord Chaos Testing **[MetalBear](https://daily.dev/sources/metalbear)** · 7 min read · 31 upvotes · 2 comments ## Summary MetalBear has launched mirrord Chaos Testing, a feature that lets developers deliberately inject latency or connection failures into their own service's outgoing connections during a local mirrord session, without affecting a shared environment or other users. Chaos rules pair a selector (destination and percentage) with an effect (latency or connection_error with reset/timed_out/refused variants), letting developers verify retry and fallback logic against realistic partial failures like a slow Redis cache. It works with mirrord OSS and CLI version 3.241.0 or later, requiring no operator or Teams license, and can be managed via CLI subcommands, a local UI, REST endpoints, or an AI coding agent using the mirrord skills plugin. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How do I simulate a slow or failing dependency for just my own service without setting up a dedicated chaos engineering environment? mirrord Chaos Testing lets you attach chaos rules to your own mirrord session so faults only affect your traffic, not the shared cluster. A rule pairs a selector (destination host:port plus a percentage of matching connections) with an effect: latency (delays reads/writes with optional jitter) or connection_error (reset, timed_out, or refused). It requires mirrord CLI 3.241.0 or later and works with mirrord OSS, no operator or Teams license needed. _daily.dev surfaces practical approaches like this for testing failure handling before it hits production._ ### What is the difference between mirrord Chaos Testing and dedicated chaos engineering tools like Chaos Mesh or LitmusChaos? Chaos Mesh and LitmusChaos inject faults into a shared environment that affects everyone using it and requires coordination, making them suited for testing a final build before release. mirrord Chaos Testing instead attaches chaos rules to an individual developer's mirrord session, so only that person's own service connections are disrupted, letting them test retry logic or fallback behavior instantly before opening a pull request. _weighing chaos testing tools? daily.dev helps developers compare approaches before picking one._ ### How can I add latency to a specific dependency connection using mirrord chaos rules? Define a chaos rule JSON file with a latency effect specifying read_ms and optional jitter_ms, paired with a selector naming the upstream host:port and a percentage of connections to affect, for example 400ms latency with 100ms jitter on 35% of connections to a Redis instance. Apply it with mirrord chaos add -s $SESSION_ID -f path/to/rule.json against an active mirrord session, or ask an AI coding agent with the mirrord skills plugin installed to generate it for you. _daily.dev helps developers keep pace with new ways to test dependency latency and failure handling._ ## Community discussion Top comments from developers on daily.dev. **@agustinbarrientos** · 1 upvotes > Chaos runs should emit a deterministic seed and an exportable manifest. CI should be able to replay the same destination, timing, failure percentage, and effect. ## Similar posts on daily.dev - [How To Get Started With Chaos Testing Using mirrord](https://daily.dev/posts/how-to-get-started-with-chaos-testing-using-mirrord-hehtl0qjo) · MetalBear · 1 upvotes · 0 comments - [Chaos Testing When Your Testers Are Agents](https://daily.dev/posts/chaos-testing-when-your-testers-are-agents-sbiz4bfsh) · MetalBear · 0 upvotes · 0 comments - [How To Prevent Token Burn Using mirrord With E2E Tests](https://daily.dev/posts/how-to-prevent-token-burn-using-mirrord-with-e2e-tests-9rav0oih4) · MetalBear · 1 upvotes · 0 comments --- Tags: [#testing](https://daily.dev/tags/testing), [#kubernetes](https://daily.dev/tags/kubernetes), [#microservices](https://daily.dev/tags/microservices) [View this post on daily.dev](https://daily.dev/posts/introducing-mirrord-chaos-testing-emvolloz5) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Introducing mirrord Chaos Testing","url":"https://daily.dev/posts/introducing-mirrord-chaos-testing-emvolloz5","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/introducing-mirrord-chaos-testing-emvolloz5"},"datePublished":"2026-08-24T07:58:10.027Z","dateModified":"2026-09-14T06:31:33.092Z","description":"MetalBear has launched mirrord Chaos Testing, a feature that lets developers deliberately inject latency or connection failures into their own service's...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/6ff7f82ef247eda6d942ec748ac09c2b?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/6ff7f82ef247eda6d942ec748ac09c2b?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"MetalBear","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"MetalBear","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/3165f5f876b147e2a160f4bf0fcaa13a","url":"https://daily.dev/sources/metalbear"},"commentCount":2,"discussionUrl":"https://daily.dev/posts/introducing-mirrord-chaos-testing-emvolloz5","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":31},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":2}],"keywords":"testing,kubernetes,microservices","timeRequired":"PT7M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"MetalBear","item":"https://daily.dev/sources/metalbear"},{"@type":"ListItem","position":3,"name":"Introducing mirrord Chaos Testing"}]} {"@context":"https://schema.org","@type":"WebPage","@id":"https://daily.dev/posts/introducing-mirrord-chaos-testing-emvolloz5","comment":[{"@type":"Comment","text":"Chaos runs should emit a deterministic seed and an exportable manifest. 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