C to XML Converter
Paste C structs or typedefs. Get clean XML back.
What this tool does
C has no built-in XML serializer. If you want an XML document that mirrors a typedef struct, you typically reach for libxml2, Expat, or you hand-write the thing character by character. Paste your C here and you skip that first round of typing — the tool emits well-formed XML that lines up with the fields, nested types, and arrays you defined.
It reads real C, not a toy subset. A typedef struct { char orderId[16]; double totalAmount; OrderItem items[2]; } Order; paired with a C99/C11 designated initializer (Order o = { .orderId = "ORD-4821", ... };) turns into a complete <Order>...</Order> tree with each member as a child element. Fixed-size char arrays are treated as strings (not byte arrays), numeric types keep their literal form, and bool from <stdbool.h> becomes true / false in the output.
Arrays and nested structs come out the way you would hand-write them. An OrderItem items[2] becomes <items><OrderItem/><OrderItem/></items>, with each element expanded. Nested typedefs are resolved to their underlying layout, so a MoneyAmount alias for double still emits a numeric value, not a dangling reference. Pointers that have no initializer become empty elements rather than being silently dropped — handy if you are using the output as a schema template for a GCC-built service that still speaks XML to older consumers.
How to use it
Three steps. Works whether you paste a single typedef or a whole header plus an initializer.
Paste your C (or try the sample)
Drop any C into the left editor — a typedef struct, a plain struct, a designated initializer, or a mix. #include directives, comments, and #define macros are fine; leave them in.
Prefer a clean example? Click Load Sample for a realistic Order typedef with nested OrderItem and Address, initialized with C99 designated-initializer syntax.
Hit Convert
Click the green Convert button. The tool walks your structs, resolves typedefs, expands nested types and arrays, and writes the XML in one pass. A short loading indicator runs while it works.
Copy the XML
The right panel fills with well-formed, indented XML. Copy it into a libxml2 test fixture, a config file your firmware reads at boot, an Expat callback test, or your documentation.
When this actually comes in handy
Embedded / firmware config templates
Bootloaders and industrial devices often read XML config from flash or SD card. Paste the C struct that describes the config, get an editable XML template that matches the layout byte-for-byte.
libxml2 / Expat test fixtures
Writing sample XML by hand for every parser test gets old. Generate the fixtures from the real typedefs your parser hydrates into — the fixtures and the types stay in sync.
Talking to legacy XML systems
Telco, defence, and healthcare C services still exchange XML with partner systems. When a new struct needs to go over the wire, this tool shows you the exact shape before you write the serializer.
Docs and schema examples
README and API reference sections that show a "typical message" are easier to keep accurate when the example is generated from the actual header. No drift between what the code reads and what the docs claim.
Common questions
Can I paste a whole header with multiple typedefs?
Yes. Paste the full header — every typedef struct is captured, nested types expand inline, and forward-declared types get resolved when their definition appears later in the paste. #include, #define, and comments are ignored for layout purposes.
Does it understand C99 / C11 designated initializers?
Yes. Order o = { .orderId = "ORD-4821", .items = { ... } }; is parsed by field name, so the XML element names match what you wrote. Positional aggregate initializers also work when the struct definition is in the same paste — the tool lines up the positions against the declared member order. See the C11 standard section 6.7.9.
How does it treat char arrays, enums, and unions?
Fixed-size char arrays are rendered as strings (the convention in almost every real C codebase), not as a list of integers. enum values are emitted as the enumerator name, not the numeric value, so the output is readable. union members are emitted as the last-assigned variant if the designated initializer makes that clear, or as an empty element with a comment if the active variant is ambiguous.
Why not just use libxml2 or Expat?
Those libraries are solid for runtime serialization, but writing the first fixture or the first config template by hand still takes time. This tool saves that. Once you have the XML shape right, plug it into libxml2 or Expat for the production path.
Is my code stored?
Your code is sent to the backend for conversion and is not persisted — we do not log the payload. As always, if the source is sensitive (proprietary protocol, safety-critical firmware, etc.), look it over before pasting.
What if the C has pointers, function pointers, or opaque types?
Object pointers with an initializer are followed to the pointee. Uninitialized pointers, function pointers, and opaque (struct Foo* with no visible definition) are emitted as empty elements rather than failing the whole conversion. This matches how you would hand-write an XML document for a struct whose pointer target is not part of the serialized payload.
Other tools you may need
C to XML is one piece of the puzzle. These tools pair well with it: