Load Toolzum once, and local tools keep running with no connection. Network tools do not — here is the exact line.
After first load — no connection needed.
Pure local math in the CalculatorShell — no fetch call anywhere in the compute path.
Image, PDF, audio and video tools process files in-browser via WebAssembly and JavaScript.
Case converters, encoders, password and UUID generators never touch the network.
The pdf.js worker ships same-origin and is precached, so PDF tools open offline too.
Each one makes a network request — verified in component code.
Every answer calls /api/ai/generate, /api/ai/generate-image or /api/ai/transcribe (see useAiProvider) — no connection, no credits spent, no answer.
WhoisLookup and DomainAvailabilityChecker fetch /api/rdap-lookup plus DNS-over-HTTPS — inherently live lookups.
UrlShortener posts each URL to /api/url-shorten, which calls third-party shortening providers server-side.
They post to /api/url-status-check and /api/fetch-page to probe live sites on your behalf.
CurrencyConverter fetches /api/currency-rates (hourly-cached upstream feed) — saved rates show, fresh rates need internet.
TranslatePdf calls the MyMemory translation API per chunk — translation is a network operation.
TempEmailInbox fetches temp addresses and messages from a worker API — mail cannot arrive offline.
PronunciationTool queries dictionaryapi.dev for definitions — cached words show, new words need internet.
The service worker (registered automatically in production only) precaches:
No manual step is required. On your first visit in production the service worker registers automatically and precaches the app shell, so repeat visits load even with flaky internet. Installing the app just adds a home-screen icon and a standalone window.
Any tool that calls fetch needs the network: AI tools (credit APIs), RDAP/whois, the shortener, live currency rates, translation, temp-mail and dictionary lookups. Pure-computation tools — calculators, converters, editors — keep working because they never make a request.
No — and we will not claim that. Local tools work fully offline after first load, but AI, lookup, shortening, live-rate, translation and inbox tools fundamentally need a connection. This page lists exactly which is which.
Offline strengthens it: with no requests leaving your device, even analytics and quota pings cannot fire. Files were already processed locally, so offline simply removes the last reason anything could leave the browser.