Free Online Converters for Developers

Most programming work involves changing something from one shape to another: a timestamp into a readable date, a number from decimal to hexadecimal, a curl command into fetch code, a YAML file into JSON. The converters on this page cover those everyday translations in one place, with a clear input, one main button and a result you can copy straight away.

They are written for people who are not experts in every format. Each converter explains what the result means, shows an example, and tells you plainly when the input cannot be converted and why, instead of returning something that only looks right. Conversions that depend on your settings, such as time zones, use the clock and rules of your own browser.

All conversion happens on your device. Your configuration files, command lines and timestamps are never uploaded, and once a converter has been opened it keeps working without a connection. If you convert the same kind of thing often, star the tool and it will appear at the top of All tools and in search.

All Converters

46 tools

JSON ↔ TOML ConverterSwitch config files between JSON and TOML

JSON ↔ YAML ConverterSwitch between JSON and YAML

cURL to Code ConverterTurn a curl command into ready code

Encode / DecodeTurn text into safe codes, and back

Base64URL & Base32 ConverterEncode text for links and codes

Unix Timestamp ConverterTurn computer time into a real date

Timezone ConverterFind the time in other cities

Number / Byte FormatterTurn bytes into KB, MB and GB

Cron ParserUnderstand a cron schedule in plain English

Base ConverterConvert binary, decimal and hex numbers

Case ConverterChange text to UPPER, lower, Title case

Slug GeneratorMake clean web addresses from titles

Subnet CIDR CalculatorWork out IP ranges for networks

HTML Entity Encoder/DecoderShow special characters safely in HTML

Regex TesterTest search patterns and see what matches

JSON String Escape / UnescapeMake text safe to put inside JSON

Unicode Character InspectorSee the code behind any character or emoji

Text to Binary / ASCIITurn text into 0s and 1s

HTML to Plain TextStrip web page code, keep the words

Emoji & Unicode EscapeWrite emoji safely in code

Gzip CompressorSqueeze text or files smaller with gzip

Zlib Deflate / InflateCompress and decompress with zlib

Brotli SandboxSee how much Brotli shrinks your files

Base85 / Ascii85Encode data with Base85

Base58 Encoder / DecoderEncode data the Bitcoin way (Base58)

Punycode ConverterUse domain names in any language

URL Double EncodingFix links that were encoded twice

Bencode Decoder / EncoderRead .torrent and bencoded data

MessagePack VisualizerRead MessagePack data

Protobuf DecoderRead Protocol Buffers messages

CBOR DecoderRead CBOR data

ASN.1 DecoderExplore certificate and key structures

Binary to DecimalConvert binary to normal numbers

Decimal to BinaryConvert numbers to binary

Decimal to HexConvert numbers to hex

RGB to HexTurn an RGB colour into hex

Epoch to DateTurn a timestamp into a date

Base64 to ImageTurn Base64 text back into an image

Hex to DecimalConvert hex to normal numbers

Hex to RGBTurn a hex colour into RGB

Roman Numeral ConverterConvert numbers to Roman numerals

NATO Phonetic AlphabetSpell words clearly on the phone

File Type CheckerFind out what a file really is

Hex DumpLook inside any file byte by byte

Base64 Image ConverterTurn an image into text code, and back

Frequently asked questions

Are conversions done on a server?

No. Every converter runs in your browser, so the text, numbers and files you convert never leave your device.

Which conversions are included?

Data formats (JSON, YAML, TOML), requests (curl to code), encodings (Base64, URL), numbers (binary, decimal, hexadecimal and byte sizes), time (Unix timestamps and time zones) and text styles (camelCase, snake_case and more).

Why does a conversion sometimes say my input is invalid?

Converters check the input first and explain what is wrong, with a line number where that helps, rather than guessing. Fix the mentioned problem and convert again; your input is never cleared.

Can I convert whole files?

Text files can be dropped onto the input box or opened with the file button. Image conversion tools accept image files up to the size shown on their page.

More tool groups

JSON tools · Data tools · All tools