# OpenHTF vs NI TestStand and LabVIEW
URL: /guides/openhtf-vs-teststand
Compare OpenHTF with NI TestStand (and LabVIEW-based test systems) for manufacturing test — sequence editor vs Python code, licensing, instrument drivers, operator interfaces, reports and databases, and what a migration involves.
NI TestStand is the incumbent test executive in many factories; LabVIEW is often the language under it. OpenHTF is the open-source, code-first alternative teams reach for when they want Python, git and no per-seat licences.
**TestStand** gives you a graphical sequence editor, a mature operator interface, database loggers and a vendor behind it, at a licence cost per development and deployment seat. **OpenHTF** gives you the same concepts — sequence, steps, limits, reports — as Python code you version in git, for free, with the operator interface and per-unit records built in and the database left to you.
OpenHTF
NI TestStand
Licence
Apache 2.0, free
Commercial; development and deployment licences per seat
Test definition
Python code (phases, decorators)
Sequence files edited in the Sequence Editor; steps call LabVIEW, C/C++, .NET, Python
Version control
Native — plain text in git
Sequence files are binary/XML; diff and merge are painful
Limits
Validators on measurements: range, percent, regex, custom
Numeric Limit / Multiple Numeric Limit / String Value step types
Flow control
`PhaseResult`, groups, checkpoints, branches, subtests, `run_if`
Preconditions, flow-control steps, loops in the editor
Instrument drivers
Your plugs over PyVISA / pyserial / vendor SDKs; a few bundled
NI drivers, IVI, LabVIEW driver libraries
Operator interface
Built-in browser Operator UI
Simple/Full OI, customisable in LabVIEW/C#
Reports
JSON test record per unit; callbacks to anything
ATML/XML/HTML reports; built-in database logger (SQL Server, Oracle, ...)
Analytics
Not included — records go to your database or TofuPilot
Not included — TestStand logs, analytics via SystemLink or third party
Multi-station
Multicast dashboard
Deployment utility; SystemLink for fleets
Skill required
Python
TestStand sequencing + LabVIEW or another step language
Support
Community (Discord, GitHub); maintained at Waymo
NI support contracts
A TestStand sequence is edited in a GUI; the logic is spread across step properties, preconditions and expressions. An OpenHTF test is a Python file:
Code review, blame, branches and CI apply directly. Engineers who already write Python for firmware tooling or data analysis do not learn a second environment.
TestStand's database logger is a real advantage out of the box: check a box and results land in SQL Server. OpenHTF stops at the record; getting it into a database is an output callback you write or a product you adopt. The record itself is richer than most TestStand schemas by default — every measurement carries value, limits, unit, marginal flag and timestamp.
NI's driver ecosystem is broad, and LabVIEW makes GUI instrument panels fast. In Python, PyVISA covers SCPI instruments, vendor SDKs cover the rest, and the plug wraps whatever you use. Writing a plug for an instrument that has a LabVIEW driver but no Python one is the main migration cost.
Licences scale with stations. A line of 20 stations is 20 deployment licences plus development seats, renewed. OpenHTF's cost is engineering time — usually less than a licence cycle for a Python-fluent team, more for a LabVIEW-only team.
The team is LabVIEW-first and has years of drivers and VIs.
Non-programmers must edit sequences in a GUI.
A compliance process already validates TestStand and its reports.
Vendor support with SLAs is a requirement.
Most sequences map one-to-one: steps become phases, numeric limit steps become measurements with `in_range`, preconditions become `run_if` or branches, cleanup steps become a phase group's teardown. The TestStand migration guide walks through it, including how to keep both systems running during the transition.