A 1 MB JSON test file

About this file

A 1 MB test file in JSON format, sized to exactly 1,048,578 bytes. Free to download with no signup, for verifying upload limits and file-handling behaviour.

The MD5, SHA-1 and SHA-256 values listed above are the real digests of this file. Recomputing them after download confirms the transfer was not corrupted, and they double as known-good expected values when testing a hashing library.

What this size means in practice

1 MB is exactly the nginx client_max_body_size default (1m). Behind a reverse proxy where nobody set that directive, anything larger never reaches your application — nginx answers 413 Request Entity Too Large itself.

That makes it the ideal size for reproducing the classic incident where the app limit was raised to 10 MB yet uploads still fail at 1 MB. If the 413 never appears in your application log, the cause is almost always the proxy layer in front of it.

Getting a feel for this size

On a 10 Mbps link the transfer takes roughly 839 ms, and about 84 ms at 100 Mbps. Base64-encoded it grows to roughly 1,365 KB.

Treated as an array of records of roughly 180 bytes each including keys, this size holds about 5,825 records — enough to judge whether you can hold them all in memory or should switch to a streaming parser. It is a rough estimate; the real figure depends heavily on your structure.

What to check for this format

JSON is likewise plain text and is UTF-8 by specification. Syntactic validity cannot be judged without parsing the whole document, so the larger the file, the more the cost of "read everything just to validate" matters.

• Whether large JSON goes through a streaming parser or is expanded into memory all at once
• Whether nesting depth is capped — deeply nested JSON can exhaust a parser's stack
• Whether large integers keep their precision — JavaScript numbers lose accuracy beyond 2^53