Last updated: 20 July 2026
These are convenience utilities, not production tooling. Verify any output before it reaches a configuration file, a migration, a deployment or a security control. Every tool here is implemented carefully and tested, but a browser utility is not a substitute for the canonical tool in your own environment when the result matters.
Base64 is not security
This deserves its own section because the misunderstanding causes real incidents. Base64 is a reversible transport encoding. It provides no confidentiality, no integrity and no authentication. Anyone can decode it instantly, automated scanners do so by default, and the character distribution is immediately recognisable.
A credential stored Base64-encoded is a credential stored in plaintext. If you need secrecy, use encryption. If you need integrity, use a MAC or a signature. Base64 sometimes wraps encrypted data so ciphertext can travel through a text channel — in that arrangement the encryption is doing all the work and the encoding is doing none of it.
What each tool assumes, and where it stops
| Tool | Scope | Where it stops |
|---|---|---|
| Base64 Encoder & Decoder | RFC 4648 standard and URL-safe alphabets; UTF-8 text and local files up to 2 MB | Cannot verify signatures, decrypt anything, or detect the original character set of non-UTF-8 data. Binary output rendered as text will show replacement characters. |
| Unix Timestamp Converter | Seconds, milliseconds and microseconds; timezone display via the browser's Intl API | Ignores leap seconds, as Unix time itself does. Timezone data comes from your browser and may lag recent legislative changes. Historical dates before 1970 are supported but many systems reject them. |
| Number Base Converter | Integers in any base 2–36, arbitrary precision via BigInt | Integers only — no fractional conversion. Negative values are shown as sign-and-magnitude, not two's complement, because two's complement requires a fixed bit width. |
| Slug Generator | Latin scripts with Unicode NFKD accent folding | Cannot transliterate scripts with no ASCII equivalent — Chinese, Arabic, Hebrew, Cyrillic, Devanagari. Those characters are stripped. Uniqueness is your application's responsibility; we only flag duplicates within one batch. |
| CIDR Subnet Calculator | IPv4 only, prefixes /0 to /32, RFC 3021 and RFC 1918 aware | No IPv6. No VLSM planning, route summarisation or overlap detection across multiple subnets. Scope detection covers common reserved ranges, not the complete IANA registry. |
Standards are authoritative, we are not
Where a page describes a specification, the specification itself governs. If this site and RFC 4648, RFC 3986, RFC 1918 or RFC 3021 disagree, the RFC is right and we have made an error we would like to hear about. The same applies to language behaviour: if a page describes what JavaScript, Python or C does and the actual implementation differs, believe the implementation.
Verify before production
Reasonable checks before acting on output from any browser utility, ours included:
- Round-trip it. Encode then decode, convert then convert back. A tool that survives a round trip on your actual data is very likely correct for it.
- Cross-check one value against the canonical tool in your environment — base64, date -d, ipcalc, printf '%x'.
- Test the boundaries. Empty input, maximum length, the first and last address in a range, a value one past a type limit.
- For network changes, check overlaps against your existing allocations. This calculator analyses one subnet in isolation and knows nothing about the rest of your address plan.
Browser dependencies
Some behaviour depends on your browser rather than on us. Timezone names and offsets come from the browser's bundled IANA database, which is updated with the browser. Unicode normalisation depends on the browser's Unicode version. File reading requires the FileReader API. BigInt requires a reasonably modern engine. On an old browser some tools will degrade or fail rather than return a subtly wrong answer.
Precision and display
Output is shown exactly as computed — no rounding is applied to any tool on this site, because none of these operations produce fractional results. Where a byte count, overhead percentage or host count is displayed as a rounded figure, the rounding is in the display only and is labelled as approximate where it matters.
Limitation of liability
To the fullest extent permitted by law, DevForgio and its operators accept no liability for any loss or damage arising from use of, or reliance on, output or information from this site — including data loss, corrupted payloads, misconfigured networks, broken URLs, security incidents or downtime. Your use of the site is at your own risk. This disclaimer forms part of our terms of use and should be read alongside our privacy policy.
Report an error
If a tool produces incorrect output, or an explanation misstates a specification, please tell us through the contact form or at corrections@devforgio.com, including the exact input you used. Correctness issues are fixed ahead of everything else.