validkit

Agentic-first data validation service. Validate emails, credit cards, ISBNs, IBANs, BIC/SWIFT, VINs, SSNs, EINs, domains, MAC addresses, postal codes (28 countries), hex colors, coordinates, MIME types, usernames, JWT, JSON, XML, Base64, hex, ASCII, UUIDs, IPv4/IPv6, URLs, Luhn checksums, and more. Auto-detect validation type. Plain text API, agent-driven, single Go binary. No database needed — pure stateless computation.

Quick Start

# Build
make build

# Run (dev mode, no auth)
./validkit -no-auth

# Validate an email
curl -X POST http://localhost:7700/validate/email -d '{"value":"test@example.com"}'
# valid=true type=email input=test@example.com detail=valid email address local=test domain=example.com

# Auto-detect type
curl -X POST http://localhost:7700/validate -d '{"value":"4242-4242-4242-4242"}'
# valid=true type=creditcard input=4242424242424242 detail=valid credit card number (Luhn check passed) type=visa

# Validate postal code with country
curl -X POST http://localhost:7700/validate/postal -d '{"value":"10001","country":"US"}'
# valid=true type=postal input=10001 detail=valid US ZIP code (5 digits or ZIP+4) country=US

# Get JSON output
curl -X POST http://localhost:7700/validate/uuid -H 'Accept: application/json' -d '{"value":"550e8400-e29b-41d4-a716-446655440000"}'

# List all validation types
curl http://localhost:7700/types

# Batch validation
curl -X POST http://localhost:7700/batch -d '{"items":[{"type":"email","value":"a@b.com"},{"type":"uuid","value":"550e8400-e29b-41d4-a716-446655440000"}]}'

# MCP endpoint
curl -X POST http://localhost:7700/mcp -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

Validation Types

Type	Endpoint	Description
email	/validate/email	Email address (RFC 5322)
creditcard	/validate/creditcard	Credit card (Luhn + type detection)
isbn	/validate/isbn	ISBN-10 or ISBN-13
iban	/validate/iban	IBAN (mod-97 checksum)
bic	/validate/bic	BIC/SWIFT code
vin	/validate/vin	Vehicle Identification Number (17 chars, checksum)
ssn	/validate/ssn	US Social Security Number
ein	/validate/ein	US Employer Identification Number
domain	/validate/domain	Domain name
mac	/validate/mac	MAC address
postal	/validate/postal	Postal code (28 countries)
color	/validate/color	Hex color (#RGB, #RGBA, #RRGGBB, #RRGGBBAA)
coordinates	/validate/coordinates	Latitude/longitude coordinates
mime	/validate/mime	MIME type
username	/validate/username	Username/handle
jwt	/validate/jwt	JWT structure (header.payload.signature)
json	/validate/json	JSON validity
xml	/validate/xml	XML well-formedness
base64	/validate/base64	Base64 string (standard, url-safe, raw variants)
hex	/validate/hex	Hex string
ascii	/validate/ascii	ASCII string
uuid	/validate/uuid	UUID (version detection)
ipv4	/validate/ipv4	IPv4 address (class, private detection)
ipv6	/validate/ipv6	IPv6 address
url	/validate/url	URL
luhn	/validate/luhn	Luhn checksum
slug	/validate/slug	URL slug
boolean	/validate/boolean	Boolean value
numeric	/validate/numeric	Numeric string
alphanumeric	/validate/alphanumeric	Alphanumeric string
utf8	/validate/utf8	UTF-8 string
auto	/validate	Auto-detect type

Configuration

Flag	Env	Default	Description
-addr	VALIDKIT_ADDR	:7700	Listen address
-secret	VALIDKIT_SECRET	(auto)	Token signing secret
-no-auth	VALIDKIT_NO_AUTH	false	Disable auth (dev mode)

Build

make build    # CGO_ENABLED=0, single static binary
make test     # go test -race
make vet      # go vet
make run      # build + run with -no-auth

Principles

• Agent IS the interface — No UI, no SDK. The API is the product.
• Plain text by default — One labeled, grepable line per result. JSON on demand.
• Instructive errors — Every 4xx includes a hint for self-correction.
• Self-documenting — GET /help returns the operating manual.
• Single static binary — Go, CGO_ENABLED=0, zero external dependencies.
• No database — Pure stateless computation.

License

MIT