application/*
application/x-ndjson
File extensions: .ndjson, .jsonl
One JSON object per line — the standard for streaming and log formats.
What is application/x-ndjson?
application/x-ndjson streams JSON documents by placing one complete JSON value on each line, separated by newline characters. Unlike a single large JSON array, ND-JSON can be produced and consumed incrementally, which makes it perfect for logs, exports, and streaming APIs.
Typical usage
Log pipelines (Fluentd, Filebeat), Elasticsearch bulk API, streaming REST responses, big data exports.
Common gotchas
Not IANA-registered; you will see application/jsonl and application/x-jsonlines in the wild for the same format. Consumers should be tolerant of both.
HTTP header example
Response header
Content-Type: application/x-ndjson; charset=utf-8Registration status
This media type is not officially registered with IANA. It is widely used in practice, but strict clients or standards-conformant tooling may not recognize it — check your consumer's tolerance.