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100% Browser-Based · Zero Upload Risk

Extract Emails, Phone Numbers & SSNs From CSV — Without Uploading Them

8 pattern types. Luhn-algorithm credit-card validation. SSA-rule SSN validation. File contents never leave your device — extraction runs entirely in your browser.

No upload required
8 pattern types
Luhn + SSA validation
Files never leave your device

Used by compliance teams, data analysts, and engineers who cannot afford to upload sensitive files

Why Everyone Else Gets This Wrong

Online tools upload your data

Every "free" online extractor sends your file to a server. For PII — emails, phone numbers, SSNs, credit cards — that's a HIPAA violation waiting to happen.

Python scripts take 20+ minutes to write

You need to write the regex, handle encoding issues, test edge cases, validate the output, and debug the script. That's 20–30 minutes every time — if you even know Python.

grep misses validation entirely

grep finds patterns, but it can't tell you if a credit card number passes the Luhn algorithm, or if a phone number is a real US number vs. a random 10-digit string.

A raw regex matches "1234567890" as a valid phone number. Balanced mode applies NANP rules — a real US number needs a full 10 digits and an area code that doesn't start with 0 or 1.

8 Pattern Types. Real Validation. Zero Upload.

Not just regex matching — algorithmic validation where it matters

Email Addresses

Practical email matching with three validation modes. Permissive catches broad patterns; balanced excludes test addresses and common fakes; strict enforces length limits and recognizes a curated list of ~33 common TLDs.

Why alternatives fall short:
grep/Python: regex matches 'not@an@email' or '[email protected]'. Online tools: upload your contact list to a server.
Format-validated

US Phone Numbers (NANP)

Matches US/NANP numbers in common notations: (555) 867-5309, 555-867-5309, +1 555 867 5309. Requires a full 10-digit number (area code mandatory), so 7-digit fragments and digits inside longer numbers (like card numbers) are skipped. Balanced mode drops area codes starting 0 or 1. Optionally normalize matches to E.164, US, or digits-only output.

Why alternatives fall short:
grep: extracts any 10-digit sequence including SSNs, ZIP+4, and account numbers. Online tools: your customer list goes to a server.
NANP + area-code rules

Three Validation Modes

Permissive, balanced, and strict modes let you tune precision vs. recall for every pattern type. Strict mode applies the tightest rules; permissive casts the widest net.

Why alternatives fall short:
Python scripts: hardcoded regex with no mode switching. Online tools: one-size-fits-all with no control.
Full control over precision

Context View (100-char window)

See 100 characters of surrounding context for every match. Instantly distinguish a phone number in a 'contact' column vs. an account number in a 'transaction_id' column.

Why alternatives fall short:
grep: no context without -C flag, and no column awareness. Python: requires extra code to retrieve row context.
Zero ambiguity

Post-Extraction Normalization

Optionally normalize extracted values: phone numbers → E.164 (+15558675309), dates → ISO 8601 (2024-03-15), email → lowercase. Makes downstream processing trivial.

Why alternatives fall short:
Every other tool outputs raw matches — you still need to write normalization code or do it manually.
Ready for downstream use

Credit Card Luhn Validation

Extracts 13–19 digit card numbers and validates each one with the Luhn algorithm. Balanced mode also checks against known BIN prefixes (Visa: 4x, Mastercard: 51-55, Amex: 34/37, Discover: 6011).

Why alternatives fall short:
grep/Python regex: extracts any 16-digit sequence including random numbers. No Luhn check means false positives everywhere.
Luhn algorithm validated

SSN Detection + SSA Rules

Finds SSNs in NNN-NN-NNNN, NNNNNNNNN, and NNN NN NNNN formats. Strict mode applies SSA rules: no 000/666/900-999 area numbers, no 0000 group, no 0000 serial.

Why alternatives fall short:
Python regex: matches 000-00-0000 and 999-99-9999 as valid SSNs. No SSA structural rules applied.
SSA-rule validated

Sensitive Data Masking in UI

Credit card numbers and SSNs are automatically masked in the results UI (showing only last 4 digits) to prevent shoulder-surfing. Full values only appear in the exported CSV/JSON.

Why alternatives fall short:
Every other tool displays full sensitive values in the UI — a compliance risk in shared workspaces.
UI-level PCI/HIPAA safety

Pattern Extraction: SplitForge vs. The Alternatives

What you give up with grep, Python, or online tools

Capabilitygrep / regexPython + pandasOnline ToolsSplitForge
Works without coding
Needs CLI
Needs Python
Yes
Yes — browser UI
No file upload required
Local only
Local only
Uploads to server
100% browser
Luhn credit card validation
No
Manual implementation
Varies / unclear
Built-in
SSA-rule SSN validation
No
Manual implementation
No
Built-in
Sensitive data masked in UI
No
No
No
CC + SSN masked
Post-extraction normalization
Manual post-processing
Manual post-processing
No
E.164, ISO 8601, lowercase
100-char context window
Flag required
Extra code required
No
Built-in
Column-level targeting
File-level only
Yes — with code
No
Yes — UI dropdown
Deduplication by (value, type)
No
Manual code
No
Built-in
Export to CSV + JSON
Pipe to file
Yes
Usually CSV only
Both formats

Why grep, Python, and Online Tools Each Have Fatal Flaws

The right tool depends on your constraints — here's what each approach actually costs you

grep / Command Line

  • Fast for simple text searches on local files
  • Requires writing and escaping regex patterns manually
  • No CSV-awareness — treats commas as text, not delimiters
  • Zero validation — matches any sequence that fits the pattern
  • No deduplication, no normalization, no export formatting

Python + pandas

  • Full control — you write exactly what you need
  • 20–30 min to write, test, and debug a single extraction script
  • Luhn and SSA validation require additional libraries or manual code
  • Data still lives on your machine, but the barrier to entry is high
  • Every new file or pattern type requires code modifications

Online Extraction Tools

  • No coding required — paste or upload your file
  • File contents transmitted to and processed on a remote server
  • No Luhn or SSA validation in any tool we found
  • HIPAA, GDPR, and PCI-DSS violations possible for regulated data
Using an online tool to extract SSNs, credit cards, or patient identifiers likely violates HIPAA, GDPR, and/or PCI-DSS — even if the tool says 'we don't store your data.'

SplitForge

  • Upload-free: file contents never leave your browser tab
  • No coding required — point-and-click column targeting
  • Luhn algorithm built in for credit cards
  • SSA structural rules built in for SSNs
  • Three precision modes: permissive, balanced, strict
  • Context window, deduplication, and normalization included
  • Export to CSV or JSON in one click

See What Extraction Actually Looks Like

Email List Cleanup

Source column
notes (mixed text)
Contact [email protected] re: renewal. CC [email protected]
Extracted output
Balanced mode excludes noreply@, test@, and addresses with consecutive dots, and checks the TLD against a curated list of common TLDs.

Phone Number Extraction

Source column
customer_notes (freeform)
Call (415) 555-0192 or try 415.555.0193 after 5pm
Extracted output
phone_e164 (normalized)
+14155550192 · +14155550193
Normalization converts matched US numbers to E.164. Balanced mode requires a full 10-digit NANP number and drops area codes that start with 0 or 1.

Credit Card Audit

Source column
transaction_log (raw)
Charged 4532015112830366 on 2024-03-15 — Visa approval
Extracted output
card_masked (UI) / full (export)
****0366 (shown in UI) · 4532015112830366 (in CSV export)
Luhn algorithm validates each candidate. BIN prefix check confirms Visa (starts with 4). Full number only in export — never shown in browser UI.

Edge Cases We've Thought Through

Is SplitForge Pattern Extraction Right for You?

Perfect for

  • Compliance and legal teams auditing PII in existing datasets
  • Analysts extracting contact data from notes or freeform fields
  • Healthcare teams processing patient records under HIPAA constraints
  • Finance teams auditing transaction logs for exposed card numbers
  • Non-coders who need regex-level results without writing any code
  • Teams in regulated industries where file uploads are prohibited
  • One-off extractions that don't justify writing a Python script
  • QA teams validating that test datasets don't contain real PII
  • Anyone who needs to normalize phone numbers or dates to a standard format

Not ideal for

  • Non-US phone numbers: The phone engine matches US/NANP 10-digit numbers only. International numbers are not matched or normalized.
  • Custom pattern types: You can only extract the 8 built-in types. Custom regex patterns are not supported — use grep or Python for those.
  • Excel files over 200MB: Excel (.xlsx) is fully loaded into memory by SheetJS, so it's capped at 200MB. Convert large Excel to CSV first — CSV streams to disk and has no practical size limit.
  • Encoded or encrypted data: The tool works on plaintext. Hash-encoded, base64-encoded, or encrypted PII will not be detected.
  • Real-time streaming data: This is a file-based batch tool. It is not designed for streaming pipelines or API-based processing.
Need to automate this? SplitForge is a browser tool — there's no API or CLI. For pipeline automation, Python with pandas + a custom Luhn function is the right call. File too large? Use the Split tool to break your file into smaller chunks first, then extract from each chunk.

Zero-Upload Architecture: What It Actually Means

Not 'we don't store your data' — we never receive it. Your file content is parsed entirely inside your browser tab using a Web Worker. Nothing is transmitted over the network.

Web Worker isolation
Extraction runs in a dedicated Web Worker thread. The file never touches the main thread, the DOM, or any network-accessible context.
No server-side processing
There is no backend endpoint that receives your file. The server only serves static JavaScript — it never sees your data.
No persistent storage
Nothing is written to localStorage, IndexedDB, or any persistent browser store. Close the tab and the data is gone.
Verifiable in DevTools
Open Chrome DevTools → Network tab → upload a file. You will see zero outbound requests containing your file data. The architecture is auditable.

Time & Cost Savings Calculator

Estimate your annual savings vs. writing Python extraction scripts

Baseline assumption: writing and running a Python extraction script (import pandas, write regex, handle encoding, test edge cases, run, validate output) takes ~20 minutes per task. SplitForge extracts in a single pass — seconds for typical files, and measured at ~187K matches/second on a 10.8GB file (141.9M matches) in balanced mode.

1–8 pattern types

e.g., 52 = weekly

Used to calculate dollar savings

Hours saved per year
51.4
hours/year
Annual savings
$2,568
vs. Python scripting baseline
Verified Performance

~187K Matches/Second — Measured at 10GB

Measured June 2026 on Chrome, Windows 11, dev machine (Alder Lake class), 64GB RAM. Output streams to disk, so memory stays flat (an ~18MB live floor) regardless of file size. Your results will vary by machine and data density.

Throughput (10GB density)
~187K/s
Largest tested
10.8GB
Matches extracted (10GB)
141.9M
Live heap floor
~18MB (flat)
Test configuration: Chrome · Windows 11 · dev machine (Alder Lake class) · 64GB RAM · June 2026
Operation: Email extraction, 10.8GB CSV, 141.9M matches (high-density config)
Method: TRUE-10GB gate, forced-GC heap sampling, June 2026
Variance: ±15–20% by hardware/browser

Frequently Asked Questions

Extract Emails, Phones & SSNs — Without the Upload Risk

8 pattern types. Luhn + SSA validation. Context window. Normalization. All in your browser, all free.

No file upload — 100% browser processing
Luhn algorithm + SSA structural rules
Files never leave your device
Export to CSV or JSON in one click

Also try: Data Masking · Data Cleaner · Data Validator · Remove Duplicates