•9 min read
HTML to JSX: className, Styles, SVG, and Event Handler Conversion
Convert HTML to JSX: attribute renames (className, htmlFor), style objects, self-closing tags, event handlers, SVG conversion, and when to use dangerouslySetInnerHTML.
Blog
Articles, tutorials, and updates about developer tools and productivity.
•10 min read
cURL to Code: Converting curl Commands to fetch, requests, and axios
Translate curl commands to code: flag anatomy, mapping to JS fetch / Python requests / axios / Go, cookie handling, auth patterns, and multipart uploads with working examples.
•10 min read
JSON to TypeScript Types: Structural Inference, Nullable Fields, and Runtime Validation
Generate TypeScript from JSON: how Quicktype infers types, nullable vs optional fields, recursive types, Go/Python/Rust targets, and adding runtime validation with Zod.
•11 min read
HMAC Webhook Signatures: Verifying Stripe, GitHub, and Slack Webhooks
Verify webhook signatures with HMAC: Stripe-Signature and X-Hub-Signature-256 formats, timing-safe comparison, replay protection with timestamps, and key rotation strategies.
•11 min read
TOTP Guide: How Authenticator Apps Work (RFC 6238 Explained)
How TOTP authenticator apps work: RFC 6238 + RFC 4226, HMAC-SHA1 truncation, 30-second windows, Base32 secrets, otpauth URI format, and backup codes best practices.
•11 min read
RSA Keys Guide: Generation, Formats (PEM/DER/JWK), and Storage
Generate and store RSA keys correctly: 2048 vs 4096 sizes, PEM vs DER vs JWK formats, PKCS#1 vs PKCS#8, RSA vs ECDSA vs Ed25519, and SSH key workflow.
•10 min read
bcrypt Guide: Cost Factor, 72-Byte Limit, and Upgrade Strategies
Hash passwords with bcrypt: why SHA-256 is wrong for passwords, cost factor math, built-in salting, 72-byte truncation, bcrypt vs Argon2 vs scrypt, and upgrading cost over time.
•10 min read
YAML vs TOML: Syntax, Type Inference, and Ecosystem Fit
YAML vs TOML compared: syntax philosophies, multiline strings, arrays of tables, implicit type gotchas (the Norway NO problem), and when each format wins.
•9 min read
IBAN Validation Guide: Structure, mod-97 Algorithm, and Country Formats
Validate IBANs correctly: structure (country code + check digits + BBAN), mod-97 algorithm step by step, country-specific lengths, and payment form UX best practices.
•10 min read
URL Parser Guide: Components, Encoding, and the JavaScript URL API
Parse URLs correctly: RFC 3986 components, encoding rules per component, JavaScript URL API, IDN/Punycode, and common bugs like double-encoding and fragment stripping.
•9 min read
User-Agent Parsing Guide: UA Reduction, Client Hints, and Bot Detection
Parse user-agent strings in 2026: why UA sniffing is unreliable, UA reduction initiative, Client Hints (Sec-CH-UA), bot detection, and legitimate parsing libraries.
•11 min read
JSON Schema Validation Guide: Drafts, $ref, and CI Integration
Validate JSON with JSON Schema: draft-07 vs 2020-12 differences, core keywords, $ref and $defs, conditional validation, OpenAPI relationship, and ajv/zod/valibot tooling.
•8 min read
Base58 Encoding Guide: Bitcoin Addresses, IPFS, and Why 0/O/l/I Are Out
Understand Base58: Bitcoin's alphabet choice, Base58Check checksumming, IPFS CID format, size comparison with Base64, and when to pick Base58 over other encodings.
•8 min read
Hex to ASCII Guide: Reading Hex Dumps, Bytes, and UTF-8
Hex and ASCII essentials: byte-to-hex mapping, reading hexdump/xxd output, debugging network payloads, crypto hex outputs, and UTF-8 multi-byte sequences.
•8 min read
Data Size Units Guide: KiB vs KB, TB vs TiB, and Bits vs Bytes
Why 1 TB shows as 931 GiB: IEC binary vs SI decimal prefixes, bits vs bytes in network bandwidth, formatting helpers, and platform differences (Windows vs macOS).
•10 min read
IPv4 CIDR Subnetting: VPC Design, Subnet Masks, and VLSM
Master IPv4 subnetting: CIDR notation, prefix length math, network vs broadcast addresses, VLSM, RFC 1918 ranges, and AWS VPC / Kubernetes / Docker sizing patterns.
•9 min read
IPv6 for Developers: Address Shortening, Scopes, and Dual Stack
IPv6 essentials for app code: 128-bit addresses, :: shortening, global vs link-local scopes, /64 subnetting, URL bracket syntax, and dual-stack socket patterns.
•10 min read
String Escaping Guide: JSON, HTML, URL, SQL, Shell, and Regex
Escape strings for every context: JSON backslash sequences, HTML entities, URL percent-encoding, SQL quotes, shell quoting, regex metachars, and cross-context bugs.
•7 min read
Sort Lines, Remove Duplicates, and Clean Up Text
Line manipulation for developers: sort strategies (locale-aware, numeric, version), deduplication (case, whitespace, Unicode), empty line removal, and CLI equivalents.
•9 min read
Regex Find and Replace: Capture Groups, Backreferences, and Pitfalls
Master regex replace: capture groups, backreferences ($1, \1), greedy vs non-greedy, multiline mode, case preservation, and ReDoS pitfalls across JS/Python/sed.