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smartdevbox
Open SmartDevBox — free, no sign-up91+ tools · 100% client-side · no account required
Privacy & Security

100% Client-Side

Your data never leaves your browser — not even a byte. Every one of the 91+ tools runs entirely in the browser using client-side JavaScript.

How It Works

When you paste a JWT token, format a JSON blob, decode a Base64 string, inspect an X.509 certificate, or compute a SHA-256 hash, all processing happens locally on your machine. Nothing is sent to a server.

This is not a policy statement — it is an architectural fact. There is no server-side endpoint that receives tool input. SmartDevBox is a static Next.js application served from Cloudflare Pages; once loaded, it operates entirely offline. You can verify this at any time by opening your browser's Network panel and observing that pasting data generates no outbound requests.

Open DevTools → Network tab → paste data into SmartDevBox. You will see zero outbound requests (other than the standard Google Analytics pageview ping, which contains no tool input).

Why This Matters

Developers routinely work with sensitive data. Pasting any of the following into a tool that has a server backend is a security risk — even if the provider has a privacy policy. With SmartDevBox, there is no backend to leak to. The risk is structurally zero.

JWT tokensContain auth claims and are often long-lived.
API keys & secretsEmbedded in JSON config blobs or .env files.
X.509 certificatesMay reveal internal infrastructure details.
Database exportsCSV or JSON files containing PII or business data.
API responsesProprietary schema and field names.
Code snippetsUnreleased features, internal logic.

No Account. No Sign-Up. No Tracking of Inputs.

SmartDevBox requires no account and no sign-up. There is no user session on the server because there is no server handling your tool input. Your results are never stored, logged, or associated with any identifier.

SmartDevBox uses Google Analytics (G-6Q9YWVQLYN) to measure aggregate page traffic. This is standard web analytics and does not include tool input content. No content you paste into SmartDevBox is ever captured by analytics.

The One Optional Exception: AI Mode

SmartDevBox includes an optional AI-assisted detection mode. When enabled, for ambiguous inputs where the local heuristic engine is uncertain, SmartDevBox sends a short format-detection query to the OpenAI API.

  • Disabled by default — must be explicitly activated
  • Your own API key — SmartDevBox does not proxy an OpenAI key
  • Limited scope — only the input text is sent for classification
  • Clearly indicated — an AI badge appears in the Detection Bar when active

If your data must never leave your machine under any circumstances, keep AI mode disabled (the default). All 91+ tools work fully without it.

Offline Use

Because SmartDevBox is a static client-side application, it can be loaded once and used without an internet connection. After the page assets are cached by your browser, all tools continue to function offline. There is no server-side dependency for any core tool functionality.

Data Stored Locally

SmartDevBox uses localStorage (via Zustand persist) to remember UI preferences — dark/light theme, sidebar state, recently used tools. This data never leaves your machine. Clear it at any time by clearing browser local storage for smartdevbox.com.

SmartDevBox Privacy vs Server-Side Tools

Many developer utility sites process your input on their servers — your JWT, certificate, or JSON is sent over the network, logged in access logs, and potentially retained. SmartDevBox is architected to make server transmission architecturally impossible for the 91 built-in tools:

Server-side toolsYour input is sent as an HTTP request. It appears in server access logs. The provider's privacy policy governs retention and use.
SmartDevBox (client-side)All 91 tools run in your browser tab. No HTTP request is made when you paste. There is no server to receive or log your input.

You can verify this yourself: open DevTools → Network tab → paste a JWT or certificate into SmartDevBox. You will see no outbound requests to any server. (With optional AI mode enabled, you will see a request to api.openai.com only.)

Frequently Asked Questions

Is it safe to paste a JWT token?

Yes, as long as AI mode is disabled (the default). The JWT Inspector and JWT Encoder run entirely in the browser. Your token is never sent anywhere.

Can I verify that no data is sent to a server?

Yes. Open DevTools → Network tab → paste data. You will see no outbound fetch requests to any server. With AI mode enabled you will see a request to api.openai.com.

Does SmartDevBox work in air-gapped environments?

Yes, after initial load. Once the application assets are cached, all tools work without network access. For fully air-gapped setups, you can self-host the application — it is a standard Next.js static export.

What does Google Analytics collect?

Page URL, referrer, browser, approximate geographic region, and session duration. It does not receive the content you paste into tools.

Continue reading

Auto DetectionPaste anything — SmartDevBox identifies the format instantly.All 91+ ToolsBrowse the complete built-in tool list across all 6 categories.Plugin SystemAdd your own tools — they work exactly like built-in ones.