Add SnapAPI (api-snap.com)

[niklastmk]

Description

This PR adds SnapAPI to the OpenAPI directory.

SnapAPI is a developer utility API platform that bundles 13+ common tools into a single REST API behind one API key. It provides:

• QR code generation (PNG/SVG)
• Webpage screenshots (headless browser)
• HTML to PDF conversion
• Image resize and format conversion (PNG, WebP, JPEG, AVIF)
• Cryptographic hashing (MD5, SHA-1, SHA-256, SHA-512, SHA-3)
• UUID / nanoid generation
• URL metadata and Open Graph tag extraction
• Base64 encode/decode
• JWT decode
• Color format conversion (hex, RGB, HSL)
• Lorem ipsum text generation
• Markdown to HTML conversion
• SVG placeholder image generation

Free tier: 100 calls/month, no credit card required.

Spec details

Field	Value
Provider	api-snap.com
Spec URL	https://api-snap.com/openapi.json
Format	OpenAPI 3.0.3
Official	Yes (by API owner)
Category	developer_tools

The OpenAPI spec is hosted at a stable URL (https://api-snap.com/openapi.json) and will remain current.