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API · /regex-api

Regex API

healthy 4,763 Subscribers

Run regular expressions server-side without the ReDoS risk. Test whether a pattern matches, extract all matches with their positions and capture groups (numbered and named), replace with a substitution pattern, or split text — all with the familiar JavaScript regex flags (g, i, m, s, u, y). Every evaluation runs in an isolated sandbox with a hard timeout, so a catastrophic-backtracking pattern can never hang your service; you get a clear timeout error instead. Inputs accept GET query parameters or a JSON POST body. Pure local compute with no third-party upstream, so responses are instant and the service is always available. Ideal for no-code and automation platforms, data-cleaning pipelines, form and input validation, log parsing and content tooling.

#regex #regexp #pattern #match #text #dev-tools
api.oanor.com/regex-api
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Machine-readable spec so AI agents can integrate this API.

/api/regex-api/openapi.json
/api/regex-api/llms.txt

Discovery: GET /api/index.json lists every API.

Regex API — live data on the oanor API marketplace

API health

healthy
Uptime
100.00%
Server probes · 24h
Avg latency
114 ms
Server probes · 24h
Subscribers
4,763
active
Total calls
76
last 7 days
status Full status page → · 12 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

Free

  • 1,000 calls / month
  • 2 requests / second
  • Hard cap (429 above quota, no overage)
  • 1,000 requests/month, 2 req/s
  • Test, match, replace & split
  • Numbered & named capture groups
  • No credit card
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Basic

€4.00 /month

  • 50,000 calls / month
  • 8 requests / second
  • Hard cap (429 above quota, no overage)
  • 50,000 requests/month, 8 req/s
  • All JS flags (g i m s u y)
  • ReDoS-safe sandboxed execution
  • Commercial use, email support
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Pro

€13.00 /month

  • 500,000 calls / month
  • 25 requests / second
  • Hard cap (429 above quota, no overage)
  • 500,000 requests/month, 25 req/s
  • High-volume text processing
  • Match positions & groups
  • Priority email support
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Mega

€29.00 /month

  • 3,000,000 calls / month
  • 60 requests / second
  • Hard cap (429 above quota, no overage)
  • 3,000,000 requests/month, 60 req/s
  • Pipeline & automation scale
  • Maximum concurrency
  • Priority support
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Escape API

Escape a string so it is safe to drop into a specific context. Pick a target — a regular expression (so the text matches literally), a shell command (POSIX single-quote wrapping), a JSON string, a CSV field (RFC 4180 quoting) or a SQL string literal — and get back the correctly escaped value, plus a short note on the rule applied. The contexts endpoint lists every target with a worked example. Perfect for code generation, building commands and queries, templating and data export, and safely interpolating user input. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. The SQL context is a quoted literal for convenience, not a replacement for parameterised queries. Distinct from base64/hex/URL/HTML-entity encoders.

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 Keyboard Layout API — oanor API marketplace

Keyboard Layout API

Re-map text between keyboard layouts — the fix for text typed with the keyboard set to the wrong layout. The remap endpoint takes text, a source layout and a target layout, and rewrites each character to the one produced by the same physical key on the other layout. So text accidentally typed on a Dvorak-configured keyboard while you meant QWERTY (or the reverse) is recovered exactly, and because the mapping is position-preserving it round-trips perfectly. It supports QWERTY (US), Dvorak and Colemak, including the shifted symbols, and leaves characters that are not on a remappable key (spaces and accents) untouched. The layouts endpoint returns the full key map for each layout. Everything is computed locally and deterministically, so it is instant and private. Ideal for fixing wrong-layout typing, building text editors and IME tools, layout-learning aids, and cross-layout search. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This remaps between keyboard layouts; for classical ciphers (Caesar, ROT13, Morse) use a cipher API.

api.oanor.com/keyboardlayout-api

 Entropy API — oanor API marketplace

Entropy API

Measure the information content of text. The analyze endpoint computes the Shannon entropy in bits per symbol, the total information in bits and bytes, the maximum possible entropy for the alphabet that was actually used, and a normalized 0–1 score that says how uniform (random-looking) the distribution is — over Unicode code points or raw UTF-8 bytes. The frequency endpoint returns the full character-frequency distribution, most common symbol first, with counts and percentages, showing control characters escaped and bytes as hex. It is exact, deterministic and runs entirely locally with no network calls, so it is instant and private. Ideal for randomness and password-quality checks, estimating how compressible data is, language and classical-cipher analysis, spotting low-variety or repetitive input, and feature extraction for text classification. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This measures information content; for password-strength scoring use a password API, for number statistics use a statistics API, and for grapheme/character counts use a text-segmentation API.

api.oanor.com/entropy-api

 N-gram API — oanor API marketplace

N-gram API

Generate n-grams from text, with frequency counts — entirely locally. The ngrams endpoint breaks text into contiguous sequences of n tokens and returns each distinct n-gram with how often it occurs, ranked by frequency: word n-grams (unigrams, bigrams, trigrams and beyond) for phrase and collocation analysis, or character n-grams (shingles) for fuzzy matching, language detection and indexing. The range endpoint produces every size from a minimum to a maximum in a single call (for example 1–3 grams), which is exactly what you need to build feature vectors. Choose word or character mode, whether to lower-case first, and a top-N limit to keep only the most frequent. Word tokenization is Unicode-aware and keeps internal apostrophes and hyphens (don't, well-known) as single tokens. Everything runs locally and deterministically, so it is fast and private. Ideal for text mining and NLP feature extraction, language modelling and autocomplete, search indexing and shingling, plagiarism and similarity detection, and keyword and collocation analysis. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This produces n-grams and counts; for extractive summaries and keywords use a summarize API and for grapheme/character counting use a text-segmentation API.

api.oanor.com/ngram-api

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Regex API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Regex API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Regex API?
Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.
How much does Regex API cost?
Regex API has a free tier with 100 calls / month. Paid plans start at €4.00 / month with higher quotas and faster rate limits.
Can I cancel my subscription anytime?
Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.
Is Regex API GDPR-compliant?
All requests to Regex API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.

Pick an endpoint from the list on the left to see its details and try it.

Code snippets

Sign up to get an API key, then call any path under your slug.

curl https://api.oanor.com/regex-api/SOME_PATH \
  -H "x-oanor-key: oanor_test_..."
const res = await fetch("https://api.oanor.com/regex-api/SOME_PATH", {
  headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();
$ch = curl_init("https://api.oanor.com/regex-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);
import requests
r = requests.get(
    "https://api.oanor.com/regex-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

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