Luzo - Design and debug API workflows visually
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Luzo is a desktop-first, open-source tool for building, running, and debugging multi-step API workflows. Instead of treating requests as isolated calls, it lets you design dependency-aware flows, pass variables between steps, inspect execution through a live timeline, and retry from failure without restarting everything. Built for developers and QA teams working with real API workflows, not just single requests.
Replies
Luzo
@janasundar Quick question: for someone chaining APIs daily, how does the visual flow builder handle conditional logic, like "if response X fails, retry or branch to Y"? Feels like a game-changer if it's intuitive. Congrats!
Luzo
@swati_paliwal Hi! That’s a great question.
Right now, Luzo focuses on making API flows easy to understand and debug:
If something fails, you can retry from that exact step without running everything again
It automatically figures out which steps depend on each other and runs them in the right order
It doesn’t support automatic “if this fails, go here” branching yet
For now it’s more about clear, step-by-step execution with strong debugging.
That kind of conditional flow is definitely something I’m looking to add next 👍
Mokkit
Hi fellow hunter! I'm also launching today (Mokkit), just checked out your product
Such a cool idea, it changes from all the AI and agent launches, I wish you success and upvoted you!
Luzo
@ugo_builds Hi fellow hunter! 👋
That means a lot, thank you! Just checked out Mokkit as well, looks really interesting 👀
Really appreciate the support and the upvote. Wishing you a great launch too 🚀
How does the live execution timeline work when you have parallel branches in a flow, does it show all steps running simultaneously or queue them visually? Congrats on the launch!
Luzo
@borrellr_ Thanks! Parallel branches show as concurrent when they’re eligible to run at the same stage, while dependent requests appear sequentially based on their execution order. Each step still keeps its own state and details for inspection.
Visualizing API dependency chains is something I've needed for a while.
When you have Celery workers chaining async tasks,
debugging which call broke the sequence is painful without a visual map.
How do you handle dependent calls where step 3 depends on
the response shape of step 1? Does Luzo let you define
conditional branching based on response validation?
Luzo
@fabrice_gangitano Thanks, that is exactly the kind of debugging pain Luzo is meant to reduce.
Under the hood, I handle dependent calls by modeling the workflow as a DAG (directed acyclic graph). So if step 3 depends on step 1, Luzo builds a dependency graph, validates it to catch cycles, and then uses topological ordering to determine the safe execution order. Independent steps can still run in parallel, while dependent ones wait for the data they need.
For data passing, a step can reference values from earlier responses using expressions like {{step1.response.body.id}}, and those get resolved at execution time so downstream steps use the latest available upstream data.
Right now Luzo is strongest at deterministic chaining and step-by-step inspection of those dependencies. Conditional branching based on response validation is the next big area I’m actively working on, so things like if/else paths, retries, and fallback flows based on response shape or failure conditions are where I’m taking it next.
Luzo
Hi everyone, Just rolled out a solid Luzo update on top of the original launch.
New in this iteration:
• Post-request scripts are now supported
• Conditional branching is built in
• Performance is smoother across the builder and execution flow
• Dependent variables are auto-recognized even after reordering steps
The goal with Luzo has always been to make multi-step API workflows easier to design, run, and debug with full context. This update pushes it further toward real workflow orchestration, especially for flows with branching, scripting, and changing dependencies.