URLdatajson

URLdatajson is a concept used to describe embedding a JSON-encoded data payload within a URL, typically as a query parameter or fragment, to accompany a web resource with machine-readable context. It is intended to complement traditional URL query strings by carrying structured, typed data that can be parsed by clients without requiring a separate HTTP body.

Structure and encoding

A URLdatajson payload is a JSON object (or array) that must be transmitted in a URL-safe form. In practice, implementations often encode the JSON string using percent-encoding or base64url to avoid issues with reserved characters and to keep the URL within practical length limits. The payload commonly resides in a parameter such as datajson or in the URL fragment after the hash symbol. Typical fields might include resource identifiers (id, type), metadata (title, timestamp), and data payload (data, attributes, relations).

Usage and examples

URLdatajson is used when a client needs to carry structured context alongside a link, enabling richer behavior in single-page apps, bookmarkable states, or lightweight API calls without a separate request body. Example: https://example.org/resource?datajson=%7B%22type%22%3A%22book%22%2C%22id%22%3A%22123%22%2C%22title%22%3A%22Web%20Engineering%22%7D. Alternatively, the JSON can be placed in the fragment as #datajson=%7B...%7D. Security considerations include avoiding exposure of sensitive data in URLs, managing URL length limits, and accounting for referer leakage.

Status and standards

URLdatajson is not an official IETF or W3C standard. It appears as a pattern in certain documents and projects to describe passing structured data via URLs. Practitioners should align with general URL encoding practices and be mindful of privacy, security, and interoperability implications.

See also

JSON, URL encoding, query string, fragment identifiers, base64url.