HEX HeroString to Hexadecimal Converter
Convert any string to hexadecimal format instantly with our free online tool. Simply enter your string and get immediate hex output—no registration required. Supports UTF-8, ASCII, and Unicode for accurate encoding of any character sequence.
How to Convert String to Hex
Paste Variable Names
Enter JSON keys, config values, or API parameters
Inspect Byte Representation
See how identifiers are stored at binary level
Compare with Payloads
Match hex output against packet captures or logs
Format for Tests
Generate hex arrays for unit test expected values
String to Hex Conversion Examples
| String Input | Hex Output | Description |
|---|---|---|
| {"status":"ok"} | 7B 22 73 74 61 74 75 73 22 3A 22 6F 6B 22 7D | JSON response string |
| accessToken | 61 63 63 65 73 73 54 6F 6B 65 6E | camelCase variable name |
| api/v2/users | 61 70 69 2F 76 32 2F 75 73 65 72 73 | API endpoint path |
| undefined | 75 6E 64 65 66 69 6E 65 64 | JavaScript null value |
| x-auth-token | 78 2D 61 75 74 68 2D 74 6F 6B 65 6E | HTTP header name |
What is String to Hex Conversion?
String to hex conversion targets programming identifiers and structured data—transforming variable names, function identifiers, API keys, configuration values, and code literals into hexadecimal for debugging, protocol analysis, and binary serialization. Software engineers convert strings like "accessToken" (becomes 61 63 63 65 73 73 54 6F 6B 65 6E) or JSON property keys to inspect exact byte representation, validate encoding in network packets, debug authentication failures caused by invisible characters, and analyze how frameworks serialize identifiers. This programming-focused tool helps reverse engineer binary protocols, troubleshoot API integrations, and understand how runtime environments handle string literals.
Developers rely on string-to-hex encoding when building language parsers, implementing custom serialization formats (MessagePack, Protocol Buffers), or debugging framework internals where identifier names affect byte-level behavior. Security researchers use it to detect injection vulnerabilities—converting suspicious variable names like "__proto__" (5F 5F 70 72 6F 74 6F 5F 5F) reveals prototype pollution attempts. Database administrators encode column names and table identifiers to diagnose charset issues in schema migrations. Unlike general text conversion, this tool emphasizes code-centric use cases: analyzing how programming constructs translate to bytes, validating API parameter encoding, and inspecting serialized object keys. For reverse conversion, use our Hex to String converter. Compare with Text to Hex for document content instead of code identifiers.
Programming Strings: Identifier & Token Reference
Essential hex values for API development, JSON processing, and security token analysis in modern applications.
JSON & API Values
Code Delimiters
Common Use Cases for String to Hex Encoding
API & Authentication
- • JWT token inspection
- • OAuth state parameter encoding
- • API key byte analysis
- • Bearer token debugging
Data Serialization
- • JSON property key encoding
- • MessagePack/Protobuf debug
- • Redis key byte inspection
- • Session storage analysis
Code Analysis & Debugging
- • Variable name byte inspection
- • Config file value encoding
- • Environment variable analysis
- • Command-line argument debug
String Conversion Advantages
Programming-Optimized
Built for developers and coders
Variable Name Encoding
Perfect for config files and code
JSON Payload Ready
Encode API data and responses
Null-Safe Handling
Properly encodes special string values
Understanding String Encoding to Hexadecimal
Programming identifiers follow language-specific naming conventions that affect byte representation—Python allows Unicode identifiers (def café() is valid), JavaScript permits $ and _ in names, PHP variables start with $, and shell scripts use underscores heavily. Converting "user_id" to hex (75 73 65 72 5F 69 64) versus "userId" (75 73 65 72 49 64) shows how naming conventions (snake_case vs camelCase) translate to different byte patterns. API gateways sometimes reject requests based on identifier byte patterns—seeing "Bearer token" as 42 65 61 72 65 72 20 74 6F 6B 65 6E reveals the space (20) that some systems interpret as header separator versus token content.
Configuration file parsers exhibit quirks around identifier encoding—YAML keys like "database:host" contain a colon (3A) that INI parsers would interpret as key-value separator. Environment variable names in Docker and Kubernetes must be valid identifiers: "API_KEY" (41 50 49 5F 4B 45 59) works, but "api.key" containing dot (2E) fails validation. Framework-specific escaping rules emerge in hex: Rails params like "user[email]" show brackets (5B 5D) that need URL encoding (%5B %5D = 25 35 42 for opening bracket) during transmission but appear as raw bytes in server logs.
Binary protocol implementations rely on exact identifier matching—gRPC method names, GraphQL field names, and Protobuf message types fail silently when byte-for-byte comparison mismatches. A field named "userID" (75 73 65 72 49 44) won't match "userId" (75 73 65 72 49 64) because uppercase D (44) differs from lowercase d (64). Redis key namespacing with "cache:user:123" shows colons (3A) as delimiters—converting to hex helps debug key collision issues when namespaces unexpectedly overlap. For decoding identifiers back to readable form, use our Hex to String converter. See all programming symbol codes in the ASCII to Hex table.
String Encoding Questions
How do I validate JWT payload encoding before signature verification?
Decode the base64 JWT segments, convert to hex, then back to string to inspect exact JSON structure. Mismatched encoding (extra whitespace, null bytes) causes signature failures even with valid keys.
Why do API keys with underscores sometimes fail validation?
Some systems reject underscores (5F hex) in identifiers. Convert your key to hex to verify the exact bytes transmitted—client encoding might transform _ to %5F (URL-encoded) or replace it entirely.
How do I debug GraphQL variable names in network traces?
Convert expected variable names like "userId" or "$input" to hex, then search packet captures for those byte sequences. This helps locate where variables appear in binary protocol buffers or BSON.
What's the hex representation of JSON structural characters?
Curly braces: 7B (left) and 7D (right). Brackets: 5B and 5D. Colon: 3A. Comma: 2C. Quote: 22. Essential for parsing raw JSON byte streams.
Can JavaScript's null, undefined, and "null" be distinguished in hex?
Yes! The string "null" is 6E 75 6C 6C (4 bytes). JavaScript represents null/undefined differently in memory, but as strings they're distinct: "undefined" = 75 6E 64 65 66 69 6E 65 64 (9 bytes).
How do environment variables appear in process memory dumps?
Linux stores env vars as NAME=VALUE with null terminators (00). In hex: "API_KEY=abc" appears as 41 50 49 5F 4B 45 59 3D 61 62 63 00. Search memory for known variable names converted to hex.
Convert hexadecimal numbers to a string of characters.
Convert text characters to hexadecimal numbers.
Convert ASCII characters to hexadecimal numbers.
Convert UTF8 characters to hexadecimal numbers.
ASCII to hex conversion table.