keyronne.com

Book Lookup by ISBN

/api/book

Look up a book by ISBN (10 or 13 digit): title, subtitle, authors, publishers, publish date, page count, subjects, and cover image. Validates the ISBN check digit first (rejecting typos unpaid) and returns both ISBN forms. Data from Open Library; attributed in every response. POST a JSON body like: {"isbn":"9780140328721"}

• isbn
• book
• library
• metadata
• lookup

1 call · 1 payer · last 30 days

Exact Math + Units + Stats

/api/calc

Exact computation LLMs cannot do reliably: evaluate arithmetic expressions (trig, logs, powers, factorials, constants), convert between 80+ units across 11 dimensions (length, mass, temperature, data, speed, energy, pressure...), and compute descriptive statistics (mean, median, stdev, percentiles) over up to 100k numbers. Deterministic, no hallucinated arithmetic.

• math
• calculator
• units
• statistics
• conversion

Card Number Validator

/api/card

Validate payment card numbers: Luhn checksum plus network detection (Visa, Mastercard, Amex, Discover, Diners, JCB, UnionPay, Maestro) with per-network length rules. Returns the network, Luhn result, and last four digits. Structure only — never that the card exists or has funds. No card data is stored or logged. POST a JSON body like: {"card":"4111 1111 1111 1111"}

• credit-card
• luhn
• validation
• payments
• bin

1 call · 1 payer · last 30 days

EVM Balance

/api/chain-balance

Native coin balance for any address on Ethereum, Base, Arbitrum, Optimism, Polygon, or BNB Chain, plus ERC-20 token balances (pass up to 10 contract addresses). Reads public chain state over JSON-RPC; no API keys. Amounts given raw and human-formatted. POST a JSON body like: {"chain":"base","address":"0xB86F95EF5FA904318Ea9Df3b59AdCe099b478fC4"}

• blockchain
• balance
• erc20
• evm
• wallet

1 call · 1 payer · last 30 days

EVM Block

/api/chain-block

Fetch a block header by number, hash, or "latest" on Ethereum, Base, Arbitrum, Optimism, Polygon, or BNB Chain: timestamp, miner, gas used/limit, base fee, transaction count, size. Public JSON-RPC, no API keys. POST a JSON body like: {"chain":"base","block":"latest"}

• blockchain
• block
• evm
• onchain
• header

2 calls · 2 payers · last 30 days

EVM Gas Price

/api/chain-gas

Current gas price and EIP-1559 fee suggestions (base fee, priority tip, suggested max fee) on Ethereum, Base, Arbitrum, Optimism, Polygon, or BNB Chain, in gwei. Public JSON-RPC, no API keys. POST a JSON body like: {"chain":"ethereum"}

• blockchain
• gas
• fees
• evm
• eip1559

2 calls · 2 payers · last 30 days

ERC-20 Token Info

/api/chain-token

ERC-20 token metadata — name, symbol, decimals, total supply — for any token contract on Ethereum, Base, Arbitrum, Optimism, Polygon, or BNB Chain. Optionally include a "holder" address to also read that wallet's balance. Public JSON-RPC reads, no API keys. POST a JSON body like: {"chain":"base","address":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"}

• blockchain
• erc20
• token
• evm
• metadata

1 call · 1 payer · last 30 days

EVM Transaction

/api/chain-tx

Look up a transaction and its receipt on Ethereum, Base, Arbitrum, Optimism, Polygon, or BNB Chain: status (success/reverted/pending), from/to, value, block, nonce, gas used and price, log count, and any contract created. Public JSON-RPC, no API keys. POST a JSON body like: {"chain":"base","hash":"0xb498053e345acd227657ef2e3de7d9fd9b861d673368419c4b18cfaea20365c8"}

• blockchain
• transaction
• receipt
• evm
• onchain

61 calls · 3 payers · last 30 days

Text Chunker for RAG

/api/chunk-text

Split long text into retrieval-ready chunks along natural boundaries — paragraphs, sentences, or markdown sections — with configurable size, overlap, character offsets and approximate token counts per chunk. Deterministic and language-agnostic. Built for RAG ingestion and embedding pipelines. POST a JSON body like: {"text":"Long document...","strategy":"paragraphs","maxChars":2000,"overlap":200}

• rag
• chunking
• embeddings
• text-splitting
• tokens

2 calls · 1 payer · last 30 days

Color Convert + Contrast

/api/color

Parse any CSS color (hex, rgb(), hsl()) and emit all three formats plus relative luminance. Compute WCAG contrast ratios against a background with AA/AAA pass-fail for normal and large text, and lighten, darken, or mix colors. Built for agents generating accessible UI themes. POST a JSON body like: {"color":"#3498db","background":"#ffffff"}

• color
• hex
• rgb
• wcag
• contrast

1 call · 1 payer · last 30 days

CSV <-> JSON

/api/csv

Convert CSV text to JSON and JSON rows back to CSV. RFC 4180 parsing (quoted fields, escaped quotes, embedded newlines), automatic delimiter detection (comma/semicolon/tab/pipe), and type coercion (numbers, booleans, nulls). Built for agents moving data between tabular and structured forms. POST a JSON body like: {"csv":"name,age,active\nAda,36,true\nBob,29,false"}

• csv
• json
• conversion
• tabular
• parsing

1 call · 1 payer · last 30 days

Timezones + Date Math

/api/datetime

The timezone conversions and date arithmetic LLMs get wrong, done exactly. Convert any ISO timestamp or Unix time into one or many IANA timezones (with UTC offset and weekday), add or subtract durations, and diff two instants into days/hours/minutes plus a humanized string. Omit "datetime" to get the current time. Uses the IANA timezone database. POST a JSON body like: {"datetime":"2026-07-08T14:30:00Z","timezone":"America/New_York"}

• datetime
• timezone
• date-math
• iso8601
• unix

1 call · 1 payer · last 30 days

Text Diff

/api/diff-text

Compare two texts with a Myers diff over lines, words, or characters. Returns structured edit operations, a standard unified diff (line mode), and similarity statistics. Built for agents tracking document revisions, verifying edits, or reviewing generated changes. POST a JSON body like: {"a":"line one\nline two\n","b":"line one\nline 2\n","mode":"lines"}

• diff
• compare
• patch
• versions
• unified-diff

3 calls · 2 payers · last 30 days

DNS Lookup

/api/dns

Resolve DNS records over DNS-over-HTTPS: A, AAAA, MX, TXT, NS, CNAME, SOA, CAA, SRV, PTR and more. Returns parsed answers with TTLs and the response status. Built for agents checking mail routing, domain config, or propagation. POST a JSON body like: {"name":"example.com","type":"MX"}

• dns
• doh
• mx
• records
• network

2 calls · 2 payers · last 30 days

Email Validator

/api/email-validate

Validate email addresses: RFC-style syntax checks, IDN domain normalization, live MX lookups with A/AAAA fallback (DNS-over-HTTPS), disposable-domain detection, role-address detection (info@, support@), free-provider flagging, and typo suggestions for popular providers (gmial.com -> gmail.com). Single address or batches up to 50. POST a JSON body like: {"emails":["[email protected]","[email protected]","[email protected]"]}

• email
• validation
• mx
• disposable
• verification

4 calls · 2 payers · last 30 days

Encode / Decode

/api/encode

Encode and decode text across base64, base64url, hex, URL-encoding, and HTML entities (UTF-8 safe). Also decodes (does not verify) JWTs into header and payload with human-readable exp/iat times. Built for wrangling tokens, data URIs, and escaped strings. POST a JSON body like: {"text":"hello world","codec":"base64","operation":"encode"}

• base64
• hex
• url-encode
• jwt
• encoding

1 call · 1 payer · last 30 days

Geocoder

/api/geocode

Forward and reverse geocoding on OpenStreetMap data: turn place names, addresses, and landmarks into coordinates with structured address components (forward), or turn lat/lon into the nearest address (reverse). Global coverage, up to 10 ranked results. ODbL attribution included in every response. POST a JSON body like: {"query":"eiffel tower, paris","limit":1}

• geocoding
• address
• coordinates
• places
• openstreetmap

1 call · 1 payer · last 30 days

Hash + HMAC

/api/hash

Compute cryptographic digests and HMACs deterministically: MD5, SHA-1, SHA-256, SHA-384, SHA-512, output as hex, base64, or base64url. Add a "key" for HMAC. Built for checksums, content addressing, and signature verification. Inputs are hashed and discarded. POST a JSON body like: {"text":"hello world","algorithm":"sha256","encoding":"hex"}

• hash
• sha256
• md5
• hmac
• checksum

2 calls · 2 payers · last 30 days

IBAN Validator

/api/iban

Validate International Bank Account Numbers: ISO 13616 country/length check plus the ISO 7064 mod-97 checksum. Returns the country, check digits, and the BBAN. Single IBAN or a batch of up to 50. Validates structure and checksum, not that the account is open. POST a JSON body like: {"iban":"DE89 3704 0044 0532 0130 00"}

• iban
• banking
• validation
• sepa
• finance

1 call · 1 payer · last 30 days

IP + CIDR Math

/api/ip

IPv4 and IPv6 address inspection and subnet math. Inspect an address (version, normalized form, classification: private/loopback/link-local/multicast/global, integer), compute a CIDR block (network, netmask, broadcast, host range, counts), or test whether an address falls inside a range. Deterministic, no lookups. POST a JSON body like: {"cidr":"192.168.1.0/24"}

• ip
• cidr
• subnet
• ipv6
• network

1 call · 1 payer · last 30 days

JSON Repair

/api/json-repair

Repair malformed JSON text into valid parsed JSON: markdown code fences, single quotes, smart quotes, unquoted keys, trailing commas, comments, Python literals (True/None), raw newlines in strings, and truncated output (auto-closes strings, arrays and objects). Returns the parsed value plus a log of every repair applied. Built for LLM output that almost parses. POST a JSON body like: {"text":"```json\n{name: 'Ada', age: 36, tags: ['x',], active: True"}

• json
• repair
• llm-outputs
• parsing
• malformed

6 calls · 5 payers · last 30 days

Web to Markdown

/api/markdown

Convert a web page (by URL) or raw HTML into clean, readable Markdown plus structured metadata (title, description, Open Graph tags, canonical URL, language). Strips scripts, styles and boilerplate tags; preserves headings, links, images, lists, code blocks and tables. Built for agents that need web content as LLM-ready text. POST a JSON body like: {"url":"https://example.com/article"}

• markdown
• html
• scraping
• content
• metadata

3 calls · 2 payers · last 30 days

Phone Validator

/api/phone

Validate and parse phone numbers in international E.164 form: extract the country calling code and region, the national number, and the canonical +E.164 string. Single number or a batch of up to 50. Format validation, not a line-in-service check. POST a JSON body like: {"phone":"+14155552671"}

• phone
• e164
• validation
• telephone
• msisdn

4 calls · 3 payers · last 30 days

Crypto & Token Prices

/api/price

Current USD prices for any crypto asset: majors by ticker (BTC, ETH, SOL), anything else by CoinGecko id or chain + contract address — so long-tail meme tokens work too. Up to 25 assets per call with per-asset confidence scores and timestamps. Crypto only; no equities or ETFs. POST a JSON body like: {"symbols":["BTC","ETH","pepe"]}

• price
• crypto
• token
• market
• defi

2 calls · 2 payers · last 30 days

Directions + Travel Times

/api/route

Point-to-point directions between 2-10 stops by car, bike, or on foot: total and per-leg distance and travel time, plus route geometry as an encoded polyline. Stops can be place names (geocoded automatically) or lat/lon coordinates. Generic travel and delivery routing on OpenStreetMap road data, global coverage. POST a JSON body like: {"stops":["paris","lyon"],"mode":"car"}

• routing
• directions
• travel-time
• distance
• openstreetmap

1 call · 1 payer · last 30 days

Secret Generator

/api/secret

Generate cryptographic secrets with CSPRNG randomness and honest entropy accounting: random bytes (hex/base64/base64url), passwords with character-class guarantees, pronounceable strings, UUIDs, prefixed API keys, TOTP seeds (base32), and asymmetric keypairs (Ed25519, ECDSA P-256, RSA-2048) as PEM + JWK. Unbiased rejection sampling. Secrets are never stored or logged. POST a JSON body like: {"type":"password","length":24,"symbols":true,"count":2}

• secrets
• random
• password
• keypair
• crypto

2 calls · 1 payer · last 30 days

Text Similarity + Dedup

/api/similarity

Compute pairwise text similarity, find near-duplicates, and cluster a batch of texts (2–300 items). Character n-gram cosine similarity: language-agnostic, robust to small edits, no model calls. Returns similar pairs above a threshold, connected-component clusters, and the full matrix for small batches. POST a JSON body like: {"texts":["hello world","hello world!","unrelated"],"threshold":0.8}

• similarity
• dedup
• clustering
• text
• nlp

2 calls · 1 payer · last 30 days

JSON Schema Validator

/api/validate-json

Validate a JSON value against a JSON Schema and coerce common LLM-output mistakes (numbers as strings, stringified booleans, scalars where arrays are expected, missing defaults, extra properties). Returns the coerced value plus a structured error report. Built for cleaning up LLM tool-call arguments and structured outputs. POST a JSON body like: {"schema":{"type":"object","required":["name","age"],"properties":{"name":{"type":"string"},"age":{"type":"integer"}}},"data":{"name":"Ada","age":"36"}}

• json
• validation
• llm-outputs
• coercion
• schema

4 calls · 3 payers · last 30 days

Global Weather

/api/weather

Current conditions plus hourly and daily forecasts for anywhere on Earth. Pass a major city name or lat/lon coordinates; get temperature, wind, humidity, pressure, cloud cover, condition codes and precipitation, with up to 90 hourly and 10 daily entries. Data from MET Norway (CC BY 4.0). No API keys, one call. POST a JSON body like: {"city":"paris","hourly":12,"days":3}

• weather
• forecast
• temperature
• precipitation
• wind

2 calls · 2 payers · last 30 days

Wikipedia Search

/api/wiki

Search Wikipedia and pull article summaries in 300+ languages. Pass "query" for ranked search results (title, snippet, link) or "title" for one article's summary, description, and thumbnail. Official MediaWiki API; content is CC BY-SA 4.0, attributed in every response. POST a JSON body like: {"query":"Ada Lovelace","limit":5}

• wikipedia
• search
• reference
• knowledge
• encyclopedia

1 call · 1 payer · last 30 days