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Free Online Developer & Marine Tools

A growing library of 41+ utilities for everyday coding, content workflows, and marine navigation — JSON formatters, AIS decoders, regex testers, GPS converters, JWT debuggers and more. Everything runs in your browser; nothing is sent to a server.

Developer tools →Marine tools →SEO tools →

Developer

🧾

JSON Formatter / Validator

Format, minify, and validate JSON with syntax highlighting.

🔐

Base64 Encoder / Decoder

Encode plain text to Base64 or decode it back.

🔗

URL Encoder / Decoder

Percent-encode and decode URL components.

🔍

Regex Tester

Test regular expressions, highlight matches, and inspect groups.

🪪

JWT Decoder

Decode JWT header, payload, and signature, and check expiry.

🎨

Color Picker & Converter

Convert between HEX, RGB, and HSL with a live preview swatch.

📝

Markdown to HTML

Render Markdown to HTML with live side-by-side preview.

🔀

Diff Checker

Line-by-line diff between two texts with add/remove stats.

⏰

Cron Expression Generator

Build a cron expression visually and read it back in English.

🔣

HTML Entity Encoder / Decoder

Encode reserved/unicode characters to HTML entities and back.

🕐

Epoch & Unix Timestamp Converter

Convert Unix timestamps to human-readable dates and vice versa.

🖼️

SVG Viewer & Editor

View, edit, optimize and export SVG files online.

🗺️

GeoJSON Viewer & Validator

Visualize, validate and inspect GeoJSON data on an interactive map.

🔠

Hex / ASCII / Binary Converter

Live four-panel converter (hex / ASCII / binary / decimal) with hex dump and small file upload.

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Marine & Maritime Tools

Free online tools for marine engineers, vessel operators, and maritime developers.

📡

AIS Message Decoder

Decode AIS NMEA sentences (Types 1–3 position reports and Type 5 voyage data) at the bit level.

📻

AIS Message Encoder

Build a valid AIS Type 1 position report from form inputs with step-by-step encoding.

🧭

NMEA 0183 Sentence Parser

Auto-detect and decode 17+ NMEA 0183 sentence types with checksum validation.

🛟

NMEA 0183 Checksum Calculator

Validate or generate the XOR checksum for any NMEA 0183 sentence, with step-by-step XOR.

🛰️

NMEA 2000 PGN Decoder

Parse the 29-bit CAN identifier and decode 15+ common PGNs (heading, GPS, wind, engine, tanks, environment).

📚

NMEA 2000 PGN Lookup Table

Searchable reference of 100+ NMEA 2000 PGNs with category, rate, fields, and CSV export.

🛳️

MMSI Decoder

Decode 9-digit MMSIs into station type, MID country, and full structure breakdown.

⚓

Vessel IMO Number Validator

Validate IMO numbers using the official checksum (or generate valid ones) with batch mode.

📍

GPS Coordinate Converter

Auto-detect DD / DDM / DMS, convert between all three plus UTM and MGRS, with a live map.

🌐

Great Circle Distance Calculator

Haversine distance, bearings, midpoint, and multi-waypoint routes with map and GPX export.

🧲

Bearing & Heading Calculator

True / magnetic / compass / back bearings between two points with a live compass rose.

🌊

Tide Height — Rule of Twelfths

Estimate tide heights and stream rates hour-by-hour from HW/LW values, with a curve chart.

🧮

CRC Calculator

Compute 8/16/32-bit CRCs (IBM, CCITT, MODBUS, XMODEM, MAXIM, Castagnoli) and NMEA XOR with step-by-step option.

🎚️

Bitmask & Bitfield Decoder

8/16/32/64-bit BigInt-safe bitmask editor with clickable bits and named-field decoding (signed/enum).

🛳️

AIS Track → GeoJSON Exporter

Convert multiple AIS NMEA sentences into a GeoJSON vessel track and visualize it on an interactive map.

📡

AIVDM / AIVDO Sentence Creator

Build and encode complete AIVDM/AIVDO NMEA sentences for all major AIS message types.

📏

Maritime Speed & Unit Converter

Live converter for speed, distance, depth, pressure, temperature, and wind (with Beaufort scale).

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SEO

🏷️

Meta Tag Generator

Build SEO meta tags with character counters and a Google snippet preview.

📊

Word & Character Counter

Live word, character, sentence, paragraph and reading-time stats.

🔑

Password Generator

Generate strong random passwords with a strength meter.

🔡

Slug Generator

Turn any title into a clean, URL-friendly slug.

🤖

robots.txt Generator

Compose user-agent rules and a sitemap, then copy or download robots.txt.

📣

Open Graph Tag Generator

Build OG/Twitter meta tags and preview Facebook, X, and LinkedIn cards.

🌍

IP Address Lookup

Geolocate any IP with country, ISP, timezone, and an embedded map.

🚦

HTTP Status Code Lookup

Search HTTP status codes by number or keyword, grouped by category.

🗺️

Sitemap Generator

Turn a URL list into a valid XML sitemap with frequency and priority.

📖

Readability Score Checker

Flesch–Kincaid, Reading Ease, and Gunning Fog scores with suggestions.

Frequently asked questions

What is CodDepot?

CodDepot is a free online collection of 41+ tools for software developers, SEO professionals, and marine engineers. Everything runs in your browser — there is nothing to install and no account to create.

Are these tools really free?

Yes. Every tool on this site is free to use without limits and without sign-up. The site is funded by unobtrusive ads on the tool pages.

Do you store the data I paste in?

No. All processing happens locally in your browser. Your input never leaves your device, so the tools are safe to use with API keys, JWTs, sensitive JSON, AIS captures, or anything else you would not paste into a stranger's website.

Can I use these tools offline?

After the first load, most tools work without a network connection — they are pure client-side JavaScript. Tools that need the network (IP lookup, embedded maps) say so on their page.

Who is CodDepot for?

Backend, frontend and embedded developers needing quick encoding, regex, JWT or diff helpers; content writers and SEO specialists building meta tags, sitemaps and slugs; and vessel operators, marine engineers and maritime developers working with AIS, NMEA, GPS and IMO data.