XXF field notes

Use the tool
Understand the edge

Original, implementation-aware guides for the format decisions, browser boundaries and safety checks that do not fit inside a converter interface

13 guides6 topicsPrimary references included

JSON

2 guides

6 min read

How to format and validate JSON without leaking data

A practical workflow for reading unfamiliar JSON, finding syntax errors and keeping sensitive payloads on your device.

Read guide ↗7 min read

From JSON response to safe TypeScript types

Generate a useful first draft from real API data, then harden it for nullability, optional fields and changing backend responses.

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Data formats

3 guides

5 min read

JSON vs YAML: choosing a configuration format

Compare strict machine-friendly JSON with concise human-edited YAML and convert safely between the two.

Read guide ↗6 min read

How to convert JSON and CSV without broken rows

Handle headers, nested objects, quoted commas and spreadsheet-oriented data shapes predictably.

Read guide ↗8 min read

Mapping JSON and XML without losing attributes, order or meaning

Understand the structural mismatch between JSON values and XML documents before converting feeds, legacy APIs and integration fixtures.

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Web platform

4 guides

8 min read

Frontend encoding cheat sheet: URL, Base64 and HTML entities

Know which encoding belongs in URLs, transport wrappers and HTML text—and which problems encoding cannot solve.

Read guide ↗8 min read

How to diagnose HTTP redirect chains without hiding the first mistake

Read 301, 302, 307 and 308 responses correctly, shorten avoidable hops and test the destination seen by different clients.

Read guide ↗7 min read

Unix timestamps without seconds, milliseconds or timezone mistakes

Distinguish an instant from its display timezone, detect thousand-fold unit errors and exchange dates with explicit ISO 8601 offsets.

Read guide ↗8 min read

Format and minify CSS without changing the stylesheet's meaning

Use readable formatting for diagnosis, conservative minification for delivery and parser-based tooling when modern CSS syntax becomes complex.

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Security

2 guides

6 min read

How to inspect JWT tokens safely

Decode headers and claims without confusing readable payloads with verified identity or authorization.

Read guide ↗8 min read

SHA-256 hashes and UUIDv4 identifiers solve different problems

Use deterministic digests for exact input comparison and random identifiers for distributed records without treating either value as a password or permission.

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Images

1 guides

9 min read

Prepare web images without guessing at format, quality or dimensions

Choose PNG, JPEG or WebP based on the source, resize before delivery and judge compression at the actual display size.

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Video

1 guides

10 min read

Understand M3U8 playlists before debugging HLS playback

Separate master playlists, media playlists and segments, then check codecs, CORS, MIME types and adaptive variants in the right order.

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Editorial method

Grounded in the implementation

Each guide is checked against the corresponding XXF tool so documented inputs, outputs and limitations match the behavior visitors can test

Normative specifications and primary platform documentation appear at the end of every article for readers who need the authoritative details

Examples use synthetic data and call out decisions that require application-specific validation Read the full review standards →