Data Formats
JSON Formatter
Format & validate JSON with configurable indent.
API: json-formatter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/json-viewer
Free, no signup, runs entirely in your browser — your data never leaves your device.
71 free developer tool APIs running on Cloudflare's edge. Zero tracking, zero data collection, zero logging. Every tool also has a full client-side version on formatho.com where your data never leaves your browser.
These APIs run on the Cloudflare Workers free plan. The request quota is per account — all Formatho edge APIs above share 100,000 requests/day (resets 00:00 UTC) with 10 ms CPU and 128 MB memory per invocation. If the daily cap is exhausted, Cloudflare returns error 1027 until the UTC reset; CPU or memory overruns surface as error 1102. For unlimited use, run the browser tools on formatho.com (no server involved) or self-deploy any Worker on your own free account. Full limits: official Cloudflare docs.
Data Formats
Format & validate JSON with configurable indent.
API: json-formatter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/json-viewer
Encoders & Decoders
Unicode-safe Base64 encode & decode.
API: base64-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/base64
Encoders & Decoders
Percent-encode & decode URLs.
API: url-encoder-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/url-encoder
Hashing & Crypto
MD5 hashes for checksums & legacy use.
API: md5-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/hash-text
Generators
RFC 4122 v4 UUIDs, bulk up to 100.
API: uuid-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/uuid
Hashing & Crypto
SHA-256 hashes via Web Crypto.
API: sha256-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/hash-text
Generators
Crypto-secure random strings, 4 charsets.
API: random-string-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/token-generator
Converters
Unix ⇄ ISO/UTC, auto s/ms detection.
API: timestamp-converter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/unix-timestamp
Text & Regex
SEO-friendly URL slugs, diacritic folding.
API: slug-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/slugify-string
Hashing & Crypto
MD5, SHA-1, SHA-256, SHA-512 in one call.
API: hash-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/hash-text
Auth & Tokens
Decode JWT header, payload & claims (no verification).
API: jwt-decoder-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/jwt
Network & DevOps
Plain-English cron explanations + next run times.
API: cron-parser-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/crontab-generator
Text & Regex
camelCase, snake_case, kebab-case & 8 more in one call.
API: case-converter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/case-converter
Generators
Placeholder paragraphs/sentences, json|text|html.
API: lorem-ipsum-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools
Encoders & Decoders
Encode text to HTML entities & decode them back, Unicode-aware.
API: html-entity-encoder-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/html-entities
Generators
Crypto-secure passwords, 8–128 chars, custom charsets, bulk.
API: password-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/password-generator
Data Formats
CSV → JSON with headers, quoted fields, auto-typing, GET or POST.
API: csv-to-json-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/json-csv
Data Formats
JSON arrays → CSV with RFC 4180 escaping & custom delimiters.
API: json-to-csv-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/json-csv
Text & Regex
Test regular expressions — matches, capture & named groups, indices as JSON.
API: regex-tester-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/regex-tester
Web & SEO
HEX ⇄ RGB ⇄ HSL ⇄ HSV/CMYK + WCAG luminance in one call.
API: color-converter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/color-converter
Text & Regex
Compare two texts line by line — Myers diff, unified hunks, ignore-whitespace.
API: diff-checker-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/diff
Converters
Binary, octal, decimal, hex & any base 2-36 — BigInt-safe.
API: base-converter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/integer-base-converter
Converters
Numbers ⇄ Roman numerals, strict canonical validation.
API: roman-numeral-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/roman-numeral-converter
Network & DevOps
CIDR math: netmask, broadcast, host range, class & privacy flags.
API: subnet-calculator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/ipv4-subnet-calculator
Data Formats
Pretty-print, minify & validate XML with error line/column.
API: xml-formatter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/xml-formatter
Network & DevOps
755 ⇄ rwxr-xr-x both ways, setuid/setgid/sticky, plain English.
API: chmod-calculator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/chmod-calculator
Hashing & Crypto
HMAC signatures: SHA-1/256/384/512, hex or Base64.
API: hmac-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/hmac-generator
Network & DevOps
Any URL → protocol, host, port, path, query params, hash as JSON.
API: url-parser-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/url-parser
Encoders & Decoders
Text → UTF-8 binary/hex/codepoints and back, Unicode-safe.
API: text-to-binary-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/text-to-binary
Data Formats
JSON → YAML and YAML → JSON, block scalars & flow style, clean 400s.
API: json-yaml-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/json-yaml
Auth & Tokens
RFC 6238/4226 codes: SHA-1/256/512, 6–8 digits, otpauth:// URLs.
API: totp-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/otp-code-generator
Calculators & Validators
X% of Y, X is what % of Y, and % increase/decrease.
API: percentage-calculator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/percentage-calculator
Text & Regex
Words, characters, sentences, paragraphs, reading time, top words.
API: text-statistics-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/text-statistics
Converters
Celsius ⇄ Fahrenheit ⇄ Kelvin ⇄ Rankine, absolute-zero checks.
API: temperature-converter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/temperature-converter
Generators
Sortable 26-char ULIDs — bulk up to 100, monotonic mode, decode & validate.
API: ulid-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/ulid-generator
Calculators & Validators
ISO 13616 validation: structure, country lengths, mod-97 checksum + formatting.
API: iban-validator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/iban-validator
Network & DevOps
Any code 100-599: reason phrase, category, meaning, spec reference; class lists.
API: http-status-codes-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/http-status-codes
Web & SEO
SEO + Open Graph + Twitter meta tags from one call, with length warnings.
API: meta-tag-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/meta-tag-generator
Auth & Tokens
Sign & verify HS256/384/512 tokens — custom claims, exp/nbf checks, GET or POST.
API: jwt-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/jwt
Auth & Tokens
RFC 7617 Authorization headers: user:password ⇄ base64, Unicode-safe.
API: basic-auth-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/basic-auth-generator
Encoders & Decoders
Compress text to gzip (base64/hex) & decompress back — Unicode-safe, ratio stats.
API: gzip-converter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/gzip
Calculators & Validators
GTIN-8/12/13/14 (EAN/UPC/ITF-14) validation + GS1 mod-10 check digit calculator.
API: gtin-validator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/gtin-validator
Network & DevOps
Any User-Agent string → browser, engine, OS, device type + bot detection.
API: user-agent-parser-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/user-agent-parser
Calculators & Validators
APR → APY for any compounding frequency, plus growth projection.
API: apy-calculator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/apy-calculator
Network & DevOps
Parse Cookie & Set-Cookie headers: attributes, flags, expiry, scope, security warnings.
API: cookie-analyzer-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/cookie-analyzer
Data Formats
Validate & repair LLM JSON output: fences, prose, trailing commas, quotes, Python constants.
API: llm-json-validator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/llm-json-validator
API
All 14 tool APIs behind one versioned /v1 prefix — API keys with higher limits coming.
API: api-gateway-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools
Web & SEO
Content-Security-Policy headers from directives — token validation, best-practice warnings, report-only mode.
API: csp-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/csp-generator
Data Formats
Count CSV rows, columns & per-column fill/distinct stats — RFC 4180, delimiter auto-detect.
API: csv-counter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/csv-counter
Data Formats
Convert XML to JSON and JSON back to XML — attributes as @keys, arrays for repeats.
API: xml-json-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/xml-json
Hashing & Crypto
AES-256-GCM encrypt & decrypt — PBKDF2-SHA256 key derivation, base64 or hex envelope.
API: aes-encryption-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/encryption
Text & Regex
Convert lists between comma, newline, semicolon, tab, pipe, JSON or HTML — dedupe, sort, quote.
API: list-converter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/list-converter
Calculators & Validators
Password entropy bits, crack-time estimates for 5 attack scenarios, pattern detection & tips.
API: password-strength-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/password-strength-analyser
Privacy & Security
Redact emails, phones, credit cards (Luhn), SSNs, IBANs (mod-97) & IPv4 from text — token or mask mode.
API: pii-redactor-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/pii-redactor
Calculators & Validators
Constant-product AMM (x·y=k) LP vs HODL for any price ratio, with fee break-even & scenarios.
API: impermanent-loss-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/impermanent-loss
Privacy & Security
SHA-1/SHA-256/SHA-512 fingerprints of any X.509 certificate (PEM or DER) — hex + colon form.
API: certificate-fingerprint-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/certificate-fingerprint
Hashing & Crypto
PKCS#1 ⇄ PKCS#8, SPKI ⇄ PKCS#1 public, PEM ⇄ DER — round-trip verified, key size in bits.
API: key-format-converter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/key-format-converter
Hashing & Crypto
Ethereum keccak-256 hashes (original Keccak padding, not SHA3-256) from text or hex bytes.
API: keccak256-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/keccak256
Hashing & Crypto
Solidity 4-byte function selectors + event topic0 from any signature, bulk up to 50.
API: function-selector-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/function-selector
Hashing & Crypto
Ethereum addresses → mixed-case EIP-55 checksummed form, with per-position case validation.
API: address-checksum-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/address-checksum
Hashing & Crypto
ENSIP-2 node hash of any ENS name (alice.eth), with per-label keccak-256 labelhashes.
API: ens-namehash-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/ens-namehash
Hashing & Crypto
EIP-1014 deterministic contract addresses: keccak256(0xff ++ factory ++ salt ++ keccak256(init_code))[12:].
API: create2-calculator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/create2-calculator
Privacy & Security
Signed-PDF /ByteRange coverage analysis: unsigned/appended bytes, SubFilter, signing time, revisions.
API: pdf-signature-checker-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/pdf-signature-checker
Other
Structural JSON comparison — added/removed/changed paths, RFC 6901 pointers, optional verified JSON Patch.
API: json-diff-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/json-diff
Other
Scan any URL for HSTS, CSP & 7 more headers — A+ to F grade plus nginx/Apache/Express snippets.
API: security-headers-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/security-headers
Converters
ISO 8601 ⇄ Unix ⇄ RFC 2822/HTTP dates with any-timezone conversion — epoch s/ms/µs/ns auto-detect.
API: date-time-converter-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/date-time-converter
Hashing & Crypto
Solidity/EVM storage slots for mappings, dynamic arrays, bytes & strings via keccak-256.
API: storage-slot-calculator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/storage-slot-calculator
Hashing & Crypto
Generate RSA key pairs (2048/3072/4096): PKCS#8 + SPKI PEM, OpenSSH public key, fingerprints — never stored.
API: rsa-key-pair-generator-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/rsa-key-pair-generator
Data Formats
Render {{variable}} prompt templates with JSON vars: dot paths, missing policies, used/unused report.
API: prompt-template-renderer-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/prompt-template-renderer
Data Formats
Strict JSON linting — line/column error positions, duplicate keys, trailing commas, comments, nesting stats.
API: json-lint-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/json-lint
Privacy & Security
Parse & validate DMARC records (RFC 7489), or look up a domain's live record over DNS.
API: dmarc-parser-formatho.filesformatho.workers.dev/ · Browser tool: formatho.com/tools/dmarc-parser