FlowStorm
An omniscient time-travel debugger for Clojure and ClojureScript.
At a glance
- Editor scoreNot yet scored
- PricingFree plan
- Best forOmniscient Clojure debugging
- Free planYes
- Paid fromNone
- Supported languagesClojure, ClojureScript
- Facts checked20 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.
FlowStorm pricing
FlowStorm fact sheet
| Free plan | Yes |
|---|---|
| Paid from | None |
| 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
- GDBA free, open-source debugger with unusually broad language, target, and remote-debugging coverage.—
- LLDBA capable, free debugger for C/C++ and Apple-platform development.—
- WinDbgA free, deeply capable debugger for Windows applications, drivers, and crash analysis.—
See all FlowStorm alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Sep 2026
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