JSON Pointer is a string syntax defined in RFC 6901 for identifying a specific value within a JSON document. It uses forward slashes / as path separators, similar to file system paths or XPath. For example, /store/books/0/title navigates to the title of the first book in a store object. An empty string "" refers to the entire document root.

Since / is used as a path delimiter and ~ is the escape indicator, they must be escaped when they appear in actual JSON keys:

• ~1 → represents a literal / (slash) in a key name
• ~0 → represents a literal ~ (tilde) in a key name

For example, to access a key named "path/to~file", the pointer would be /path~1to~0file.

JSON Pointer treats array indices as numeric tokens. For instance, /items/0 accesses the first element (index 0) of the items array. If the current value is an object, the token is used as a key name (even if it looks like a number). Only when the current value is an array is the token interpreted as an integer index. Out-of-range indices will produce an error.

According to RFC 6901, an empty string "" points to the entire JSON document (the root). A single slash / technically points to a key that is an empty string "" at the root level. In practice, many implementations treat both as referring to the root, but this tool follows the strict RFC interpretation.

No. JSON Pointer is purely a read-only addressing mechanism. It only identifies a location within a JSON document. For modification operations (add, remove, replace, move, copy, test), you need JSON Patch (RFC 6902), which uses JSON Pointer expressions within its operation objects to specify target paths.

Common reasons include: (1) The pointer is missing a leading / — all non-empty pointers must start with /. (2) The key contains / or ~ but wasn't escaped — use ~1 for / and ~0 for ~. (3) You're trying to use a numeric index on an object — check if the current value is actually an array. (4) Case sensitivity — JSON keys are case-sensitive.