Regex Toolkit API: Test, Explain, and Generate Patterns via API

#api #javascript #tutorial #webdev

Regular expressions are powerful and notoriously hard to write correctly. Here's how to test, explain, and generate regex patterns via API — without memorizing syntax.

The Three Problems with Regex

Writing: Syntax differs between languages. JavaScript, Python, and Go have subtle incompatibilities.
Testing: You need sample data to verify edge cases.
Reading: Six months later, /^(?:[a-z0-9!#$%&'*+/=?^_{|}~-]+(?:.[a-z0-9!#$%&'+/=?^_{|}~-]+))/` means nothing.

Pattern Testing via API

`python
import requests

Test a regex against multiple strings at once

resp = requests.post("https://api.lazy-mac.com/regex-toolkit/test", json={
"pattern": r"^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+.[a-zA-Z]{2,}$",
"flags": "i",
"test_cases": [
"user@example.com",
"user+tag@subdomain.example.co.uk",
"not-an-email",
"missing@tld",
"@nodomain.com"
]
})

for result in resp.json()['results']:
print(f"{'✅' if result['match'] else '❌'} {result['input']}")
`

Output:
plaintext ✅ user@example.com ✅ user+tag@subdomain.example.co.uk ❌ not-an-email ❌ missing@tld ❌ @nodomain.com

Pattern Explanation

`python
resp = requests.post("https://api.lazy-mac.com/regex-toolkit/explain", json={
"pattern": r"\b\d{1,3}.\d{1,3}.\d{1,3}.\d{1,3}\b"
})

print(resp.json()['explanation'])

"Matches an IPv4 address:

\b - word boundary

\d{1,3} - 1 to 3 digits

. - literal dot

(repeated 4 times with dots between)

\b - word boundary"

Pattern Generation

`python
resp = requests.post("https://api.lazy-mac.com/regex-toolkit/generate", json={
"description": "Korean phone number format: 010-XXXX-XXXX or 02-XXX-XXXX",
"examples": ["010-1234-5678", "02-123-4567"],
"counter_examples": ["123-456-7890", "010-12-5678"]
})

print(resp.json()['pattern'])