PatternBenchBY SMARTFACTFREE JAVASCRIPT REGEX WORKBENCH
Updated
A named capture group gives part of a regular-expression match a reusable name. PatternBench shows JavaScript matches and captures, then previews replacement text separately from your original input.
Free to use. No account, email address or trial. Your work stays in your browser.
Use (?<prefix>[A-Z]{2})-(?<number>\d{4}) to name two letters and four digits. Named groups let you refer to each part clearly. A syntactic match does not prove that the item exists.
Enter your exact text and run the pattern. Check the g flag when you need all matches rather than only the first. Match positions use UTF-16 offsets, as JavaScript does.
Use $<prefix>/$<number> to reuse the named captures with a different separator. The preview leaves the original input unchanged. Replacement text is supported; replacement functions are not executed.
The explanation describes parsed syntax, not a backtracking debugger. PatternBench uses this browser’s JavaScript engine and the g, i, m, s, u and y flags. It does not provide PCRE, .NET or Python execution.
For developers, integrators and people checking exact values before using them in another system.
A USEFUL STARTING POINT
Named parts make an expression easier to inspect and reuse. Read the captured values first, then compare the replacement preview with the unchanged source.
FROM QUESTION TO EVIDENCE
Supply the JavaScript pattern and exact source text.
Check matches and named capture values.
Read replacement output separately from the original.
With the named prefix and number groups, $<prefix>/$<number> changes a matched item-code separator without converting the four captured digits to a number. Leading zeroes remain text.
WHEN CHECKS REPEAT
These SmartFACT services handle work that repeats across a team or on each job. The workbench remains free and independent.
Invited trialWhen label checks must repeat for each job, LabelRules turns requirements described in plain English into approved selection and value-check rules. It starts with an invited trial. PatternBench does not publish rules into it.
Early accessWhen expected components depend on order data, KitProof builds checklists from approved plain English rules and checks each scan against them. It is in early access, with scope agreed at onboarding.
BEFORE YOU START
A named part of a match that can be inspected and reused. JavaScript uses the (?<name>...) form.
Check whether the g flag is set and whether the pattern matches the other text.
No. The replacement is a separate preview.
Only syntax supported by the browser’s JavaScript RegExp engine is available.
Patterns and replacement text are limited to 4,096 UTF-16 code units each; samples to 100,000. Up to 1,000 matches and 64 capture groups are supported, with 200,000 retained text/output code units. Cases are limited to 50 values of 2,000 code units each. Highlighted preview shows 6,000 sample code units and the table 100 matches; complete results are used for replacement and export. The engine is the current browser’s JavaScript RegExp, not PCRE, .NET or another dialect. Matching a shape does not prove that a real-world value exists. Syntax explanations show up to 512 elements. Project files are limited to 1.5 MB. Generated snippets do not include the workbench’s worker or result limits.
Patterns, sample text, replacement text, cases and results stay in this tab’s memory. Workers run on this device and are discarded after completion, edits, cancellation or the execution limit. Nothing is uploaded, put in a page address or saved automatically. Refreshing or closing the tab discards the work. Clipboard copies, extraction exports, generated code and project files can contain your actual values. Opening a project reads the selected file locally and replaces the workbench only after validation. The tool has no analytics; these public pages offer optional suite analytics separately.
ONE SMALL JOB, DONE WELL
Open the free tool and start with one known example.
THE SMARTFACT SUITE
Automate factory decisions with rules you describe in plain English. Explore focused SmartFACT services, plus free tools for everyday checks.
Invited trialSuggested next stepDescribe label rules in plain English. Automatically select layouts, resolve customer codes and check each job before printing.
Explore LabelRules ↗Early accessTurn plain English component rules into automatic kit checklists, then check scans against the expected parts and quantities.
Explore KitProof ↗
Early accessTurn plain English rules into automatic step selection for each unit, with required evidence and a record of completed work.
Explore WorkSteps ↗
Early accessApply approved product rules and calculations automatically to turn dimensions and options into manufacturing requirements.
Register early-access interest ↗
Early accessMaintain reference tables with ConfigSheets or bring shop orders into SmartFACT through reviewed connectors. Check changes and deliver data to the products that use it.
Explore SmartFACT Data ↗
Early accessTurn plain English rules into automatic order checks and destination selection, with controlled production release.
Register early-access interest ↗
Early accessScan the work order and the parcel choice to book the courier and print the labels. Approved plain English rules recommend or choose the parcel.
Explore ParcelOffice ↗
Early accessScan an empty container to send the right refill request to stores. Approved plain English rules set the stores queue, priority, ticket printer and escalation.
Explore RefillFlow ↗
Early accessLabel each offcut, find a suitable length before cutting new stock and record what you used. Approved plain English rules decide what to keep and where it goes.
Explore RemnantRack ↗
Invited trialCheck a shared tool before handover, record who has it and keep damaged or overdue tools out of the next issue. Explore an invited trial for one factory crib.
Explore ToolCustody ↗
Invited trialReceive, put away, reserve and issue stores material with barcode checks, keeping held, reserved and available stock apart. Explore an invited trial for one stockroom.
Explore StoresFlow ↗
Invited trialFollow a lot or serial number through the records your factory already keeps, with the source of each link and the gaps shown. Explore an invited trial with two declared sources.
Explore LotTrail ↗
Early accessScan an identified unit to get its approved final-inspection checks, then record exact readings with their result, holds and release history.
Register early-access interest ↗
Invited trialBook returned units in, recover and label the usable parts, release them independently and record the unit each goes into. Explore an invited trial for one product family.
Explore ReclaimStation ↗
Free toolSee the text and key events your keyboard scanner sends. Compare them with the value you expected.
Test a scanner ↗
Free toolPrint a known PDF, measure its reference marks and compare scans from the printed codes.
Check a print ↗
Free toolCreate 100 × 50 mm bin and rack cards with Code 128 or QR, from one record or a CSV.
Make bin cards ↗
Free toolCount stock by location with a barcode scanner, compare it with a stock file and export the results. No account needed.
Start a free count ↗
Free toolSee exactly what a scanned barcode contains, with hidden characters shown and GS1 fields, check digits and dates explained. No account needed.
Inspect a barcode ↗
Free toolScan a reference and each label, see an exact match or the first difference, and download the results. No account needed.
Start a free comparison ↗
Free toolScan an item or location, note what needs attention, print a review tag and keep a review list. No account needed.
Make a free tag ↗
Free toolLoad your own parts and locations CSV, scan a code and see every location it lists. No account needed.
Start a free lookup ↗
Free toolCheck cartons, pallets or serial numbers against a list with a phone or scanner and see what is missing. No account needed.
Start a free check ↗
Free toolCheck CSV and JSON files exactly as written, preview a column mapping and compare two versions by key. No account needed.
Check a file free ↗
Free toolTime work cycles and changeovers on a phone, record interruptions with reasons and download the results. No account needed.
Start a free study ↗
Free toolLabel the offcuts on your rack, find a piece long enough before cutting new stock and record what you used. No account needed.
Track offcuts free ↗
Free toolLoad one or two CSV exports and follow a lot or serial forwards or backwards, with the row behind every link. No account needed.
Start a free trace ↗
Free toolRecord the parts recovered from each return, label them with a QR code, check them and record the unit each one goes into. No account needed.
Track recovered parts free ↗
Free toolGenerate GUIDs, UUID v4 and v7, ULIDs and Nano IDs, format and download batches, or inspect a UUID in your browser. No account needed.
Generate identifiers ↗
Free toolInspect and edit text, hex, Base64 and binary bytes in your browser, reveal hidden characters and compare byte sequences. No account needed.
Inspect some bytes ↗Free toolTest JavaScript regular expressions in your browser, inspect matches and captures, preview replacements and check expected cases. No account needed.
You are here
HelpStep-by-step guides and interactive demonstrations for the SmartFACT suite. Read the instructions, watch a task or practise with real product screens and sample data.
Open SmartFACT Help ↗