SRRRS Utilities

Local-first developer tools.

A small set of utilities used daily by the SRRRS team. Six of them run entirely in your browser — input never leaves the page. DNS lookup is the one exception and is labelled as such.

Local-first · no analytics · no input is stored or transmitted (except DNS)

TOTP 2FA

In-browser

Generate time-based one-time passwords from a Base32 secret. Shows the previous, current, and next codes so a clock drift or a slow paste never locks you out.

Subnet calculator

In-browser

Drop in an IPv4 CIDR block and get the network address, netmask, usable host range, broadcast, and total addresses.

Base64

In-browser

UTF-8 safe encode and decode. Handles multibyte text correctly — no mojibake.

Checksum

In-browser

SHA-1, SHA-256, and SHA-512 digests of any text, computed locally via the Web Crypto API.

JWT decoder

In-browser

Split a token into header and payload. Times like exp and iat are shown in plain language with a live countdown. The signature is not verified and nothing is sent anywhere.

DNS lookup

Leaves your browser

Query A, AAAA, MX, TXT, CNAME, and NS records. This is the only tool here that makes a network request — it uses Cloudflare DNS over HTTPS (1.1.1.1). The hostname you enter is sent to Cloudflare.

Timestamp

In-browser

Convert between Unix epoch and ISO 8601. Seconds and milliseconds are detected automatically.