FlowStorm

Free#13 of 27 in Debuggers

FlowStorm: A free, open-source debugger with recorded execution and backward navigation for Clojure teams. Ranked #13 of 27 in Debuggers by our editors (7.7/10); pricing: Free plan; best for omniscient Clojure debugging.

7.7/10Editor score

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At a glance

Editor score
7.7 / 10
Pricing
Free plan
Best for
Omniscient Clojure debugging
Free plan
Yes
Paid from
Free
Supported languages
Clojure, ClojureScript
Facts checked
20 Sep 2026

Where it wins
- Records execution for forward, backward, and time-based navigation
- Inspects call trees, locals, arguments, returns, stacks, and exceptions
- Supports remote debugging, programmable analysis, and custom visualization
Where it doesn't
- Language coverage is focused on Clojure and ClojureScript
- Requires comfort with interactive development workflows
- Its feature set may exceed the needs of simple breakpoint debugging

Our verdict on FlowStorm

FlowStorm is an open-source debugger for Clojure and ClojureScript, designed for developers who need to understand program behavior across an entire recorded execution rather than inspect only the current pause point. It runs on Windows, macOS, and Linux, works independently of a specific IDE, and supports Clojure applications plus ClojureScript environments in browsers, Node.js, and React Native. Its free, open-source model makes it particularly suitable for teams and individual developers already working in the Clojure ecosystem.

The defining capability is omniscient debugging through execution recording. Developers can move forward and backward through code, navigate a recorded timeline, inspect call trees and functions, and review locals, arguments, return values, and stack information. Conditional thread breakpoints and exception-unwind inspection add control when investigating complex behavior. This approach can make historical state and execution flow more accessible than conventional pause-and-step debugging, especially when the issue depends on what happened earlier in a run.

FlowStorm also extends beyond local inspection. Remote debugging is available through nREPL and WebSocket connections, while a Clojure API supports programmable analysis of recordings. Custom data visualization and value inspection provide additional ways to examine application behavior. These capabilities suit interactive development workflows and teams that want to analyze recordings programmatically. Developers focused on languages other than Clojure or ClojureScript should choose a debugger aligned with their language stack. Likewise, projects needing only straightforward breakpoint debugging may prefer a simpler tool; FlowStorm is most compelling when recorded history, time travel, and deep inspection are central requirements.

Your product? Our editors can test FlowStorm in depth and publish a review, labelled as paid · from $149/mo →

FlowStorm pricing

Plans Free planFree Free to use — no paid tier required for the core job.

See plans on flow-storm.org

FlowStorm fact sheet

Free plan	Yes
Paid from	Free
Supported languages	Clojure, ClojureScript
Target platforms	Browsers, Node.js, React Native
Remote debugging	Yes
Conditional breakpoints	Yes
Exception breakpoints	Not verified
Time-travel debugging	Yes
Core dump debugging	Not verified
Deployment	Desktop, Mobile
Platforms	Windows, macOS, Linux
Support	Docs
Built for	Solo, Small business (editorial estimate)
Pricing	Free plan
Website	flow-storm.org
Facts checked	20 Sep 2026

Alternatives to FlowStorm

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 7 Oct 2026 · How we research and update