browser-use/jev-ultrafast on GitHub
- Stars
- 19,333
- Forks
- 1,283
- Language
- Python
- License
- MIT
- Last push
- 18 Sep 2026
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Reported by the author
- Flight search
- 7.1 s
Zürich → London on Google Flights in 7.1 seconds
github.com
Jev Ultrafast is Browser Use’s browser agent, rebuilt so a single Jev call handles both parts of each step: which operation to perform (click, type text, select, scroll up, scroll down, wait, mark done, or flag blocked) and which element on the page to target. Because target options are asked speculatively alongside the operation, one network round trip returns both decisions rather than two sequential calls. A small language model is invoked only when the chosen operation is TYPE_TEXT, to write the actual text being entered; every other step needs no text generation at all.
Each observation rebuilds a fresh, indexed table of elements the page currently offers, and only the operations and targets that are actually available get offered as options, so there is no fixed action list to fall out of sync with the page. The project’s main demo runs a one-way Zürich to London search on Google Flights from one natural-language goal in 7.1 seconds, including generated text and page loads. The timer starts after the first page observation, and the run stops at the results without selecting or booking a flight.
There is no site-specific scripting or hardcoded field values behind the demo: the same policy runs against a different task by supplying a different goal.
How it uses Jev
started = time.perf_counter()
result = post_json("https://api.typesafe.ai/v1/systemone", os.environ["TYPESAFE_API_KEY"], body)
operation_answer = validate_choice(result["answers"].get("operation", {}), operations)
operation = operation_answer["choice"]
target = None
target_answer = None
probabilities = {}
if operation in targets:
# Unused target heads cannot cause an action. Validate the head selected by the operation.
target_answer = validate_choice(result["answers"].get(operation.lower() + "_target", {}), targets[operation])
target = target_answer["choice"]
choice = targets[operation][target]["id"]
probabilities = {a["id"]: target_answer["probabilities"][index] for index, a in targets[operation].items()}
else:
choice = controls[operation]["id"] if operation in controls else operationView in jev_ultrafast/model.py
