Glossary

Short, honest explanations for the technical vocabulary that shows up when you use everyday online tools.

A lot of online tools toss around terms like "OCR", "EXIF", "Base64", "PDF/A", or "QR error correction level Q" as if everyone knows what they mean. This glossary explains them in plain English, with enough technical depth that you can make informed decisions about which tool to use and how.

Each entry is short (3–5 minute read), opinionated about practical use, and links to the relevant Toolkiya tools so you can try the concept right away. If you find a term that should be here and isn't, email hello@toolkiya.com.

Formats

PDF vs PDF/A vs PDF/X vs Tagged PDF

PDF is the umbrella format. PDF/A is the archival variant for long-term preservation. PDF/X is for print production. Tagged PDF carries accessibility metadata.

JPEG vs PNG vs WebP vs AVIF

JPEG is best for photos with smooth gradients. PNG keeps sharp edges and supports transparency. WebP and AVIF are newer formats that produce smaller files at the same quality.

Encoding

Base64 Encoding

A way to represent binary data — like image bytes or encryption keys — as plain text using 64 printable ASCII characters. Not encryption, just a safe transport format.

Unicode vs ASCII

ASCII covers 128 English characters from the 1960s. Unicode covers every script in active use — Devanagari, Tamil, Chinese, emoji — across over 150,000 code points.

Technology

OCR (Optical Character Recognition)

The technology that turns a picture of text — like a scanned document or a photo of a receipt — into editable, searchable digital text.

QR Code Error Correction Levels (L, M, Q, H)

How much of a QR code can be obscured or damaged while still being readable. Levels go from L (7% recovery) to H (30% recovery), at the cost of denser code.

EXIF Metadata

Hidden data embedded inside photo files by your camera or phone — including GPS coordinates, device model, lens, ISO, and exposure settings.

WebRTC (Browser Peer-to-Peer)

The browser standard that lets two devices send video, audio, or file data directly to each other — no server in the middle holding the bytes.

Identity & Tax

Aadhaar Photo Specifications

UIDAI requires a 3.5×4.5 cm color photo, plain light background, face occupying ~60–70% of the frame, both ears visible, neutral expression, file under 100 KB.

HRA Exemption Under Section 10(13A)

Salaried Indians paying rent can claim part of their House Rent Allowance as tax-exempt — the minimum of three formulas defined in the Income Tax Act.