StepViz shows you exactly what your code does at every line — variables, memory, complexity, threads, branches — in real time. Launching with Python. C, C++, Java, JavaScript coming soon.
arr = [5, 3, 8, 1, 9, 2]
for i in range(len(arr)):
for j in range(len(arr)-i-1):
if arr[j] > arr[j+1]:
arr[j], arr[j+1] = arr[j+1], arr[j]
import threading
lock = threading.Lock()
counter = 0
def worker(n):
with lock:
counter += n
threads = [Thread(worker, i)
for i in range(1,4)]
[t.start() for t in threads]
[t.join() for t in threads]
New — threading visibility
Race conditions, deadlocks, lock contention — visualized in real time. Watch every thread's state, every lock acquisition, every shared variable mutation as it happens.
Scrub through every execution step like a video. Jump forward, backward, replay at any speed. Your bugs can't hide anymore.
def fib(n):
a, b = 0, 1
for i in range(n-1):
a, b = b, a+b
return a
Each language gets its own dedicated visualization layer — not a generic adapter. Python ships first with full algorithm detection and Pyodide WASM in-browser execution.
Database integrations follow: step through a SQL query plan, traverse a MongoDB document tree, or inspect Redis key-value state frame by frame.
Start free. Upgrade when StepViz becomes indispensable.
USD / MONTH
USD / MONTH
USD / MONTH
All paid plans include a 7-day free trial · No credit card required to start
Early access pricing — locked in for life when you sign up now
CS Students
Finally understand what your code is actually doing — not what you think it's doing. Ace your algorithms course.
Bootcamp Grads
Interview prep that actually makes sense. See the algorithm run, not just read about it.
Senior Engineers
Explain complex logic to your team without a whiteboard. Share a link, they see the execution.
Limited early access
We're inviting the first developers serious about understanding code — not just shipping it. Join the waitlist and we'll reach out personally.
No credit card. No spam. Just access.