offlineutils

developer tools

100% offline
No uploads
Free · no signup
12 tools

Developer tools

Offline developer tools are browser-only utilities for formatting, decoding, parsing, and inspecting the kinds of data developers paste into a tab every day — JSON, JWTs, regex, hashes, UUIDs, cron expressions — with no server round-trip and no risk of leaking production payloads to a third party.

Every Developer tool

About developer tools

Every developer tool on offlineutils.com runs entirely in your browser using native Web APIs (JSON.parse, crypto.subtle, RegExp, URL). That matters because the data you paste into these tools is often sensitive: production API responses, JWT bearer tokens, internal config files, customer payloads. Web-based formatters that upload your data to a server have a long history of accidental leaks. The tools here are auditable — open DevTools → Network, click any button, and watch zero requests fire.

Why pick offline developer tools

  • Zero uploads — data never leaves your browser
  • Zero tracking — no analytics, ads, cookies, or fingerprinting
  • Free, no signup or account required
  • Works offline once loaded; installable as a PWA
  • Verifiable in DevTools — zero network calls when you press a button

Frequently asked questions

Are these developer tools really offline?
Yes. Every tool runs entirely in your browser using native Web APIs. After you load a tool page once, you can open it again with the network disconnected and it still works. Open DevTools → Network and confirm zero requests when you press a button.
Why use a browser tool instead of a CLI like jq or openssl?
Two reasons. First, you do not need to install or remember syntax — paste and read. Second, you can use these on any machine (a borrowed laptop, a phone, a locked-down corporate device) where installing tooling is not an option. CLIs are still better for scripting and pipelines.
Are these tools safe for production secrets?
Yes, because nothing is uploaded. JWTs are decoded in-browser, hashes are computed via crypto.subtle locally, JSON is parsed by the native JSON.parse. The single thing to be careful about is that any text you paste is visible to whoever can see your screen and to any browser extensions that read page content — the same as any browser tab.
Do these tools work on mobile?
Yes. Every tool here is responsive and works in any modern mobile browser. Install offlineutils.com as a PWA to keep them available without an internet connection.

Other categories

Text & Content

Count, transform, compare, deduplicate and preview text.

Data

Convert between CSV, JSON and human-readable tables.

Media & Design

Resize, convert, strip metadata, scan QR — all in-browser.