Browser-local utilities

Privacy-first developer tools for time, data, APIs, DevOps, and trading calculators.

Fast static tools with React islands only where interaction is needed. Your input stays in the browser.

Tool categories

SEO guides and tool hubs

All tools

time

Unix Timestamp

Convert Unix seconds or milliseconds to ISO, UTC, local time, and back.

time

Milliseconds Timestamp

Convert JavaScript millisecond timestamps to ISO and Unix seconds.

time

ISO 8601

Convert ISO 8601 dates into UTC strings and Unix timestamps.

time

UTC Time

Convert a date or current time to UTC and local time.

time

Timezone

Convert a date to a selected IANA timezone.

time

Trading Sessions

Compare one timestamp across major trading centers.

data

JSON Formatter

Format minified JSON into readable two-space indentation.

data

JSON Validator

Validate JSON syntax locally and get parse errors.

data

JSON to TypeScript

Generate a simple TypeScript interface from a JSON object.

api

JWT Decoder

Decode JWT header and payload locally without verifying the signature.

data

Base64

Encode and decode Base64 strings locally.

api

URL Encode

Encode and decode URL components.

api

Query Parser

Parse a URL query string into JSON.

api

cURL to Fetch

Convert simple cURL commands into JavaScript fetch snippets.

devops

Cron Parser

Explain standard 5-field cron expressions.

devops

Regex Tester

Test a JavaScript regular expression against sample text.

devops

UUID

Generate random UUID v4 values in your browser.

devops

SHA256

Generate a SHA-256 hash for text locally.

trading

Position Size

Estimate trading position size from account, risk, entry, and stop values.

trading

Futures PnL

Estimate futures profit and loss from entry, exit, contracts, multiplier, and side.

trading

Candle Close Time

Calculate the close time for a crypto kline or candlestick from open time and interval.

trading

Kline Interval

Convert crypto kline intervals such as 1m, 15m, 1h, 1d, and 1w into milliseconds and seconds.

trading

Funding Fee

Estimate perpetual futures funding fees from notional size and funding rate.

trading

Liquidation Price

Estimate a simplified liquidation price from entry, leverage, side, and maintenance margin.

trading

Risk Reward

Calculate risk per unit, reward per unit, and risk/reward ratio from entry, stop, target, and side.

trading

Kelly Criterion

Calculate a simple Kelly fraction from assumed win rate and reward/risk ratio.

trading

ATR Position Size

Estimate position size using account risk, ATR, ATR multiplier, and unit value.

trading

Tick Size

Round a price to an exchange tick size using down, up, or nearest mode.

trading

Step Size

Round an order quantity to an exchange step size using down, up, or nearest mode.

trading

TradingView Alert

Parse TradingView webhook alert JSON or key=value content into formatted JSON.