20 MB Avro sample

An Avro file of exactly 20,971,520 bytes. It is a valid Apache Avro object container file file, generated by this site. Compare its checksum and test it with the parser used by your application. Use it wherever you need a 20 MB sample, test or dummy Avro file.

sample-avro-20mb.avro

20 MB20,971,520 bytes

Download 20 MB Avro

Created in your browser in a few seconds, then checked against the SHA-256 checksum. No sign-up.

Type: application/avro
SHA-256: b32bbbe3c88a5e087648f944080c2bbe0902c9eba57c1bfc486785fca41acca0
Delivery: Created in your browser from static generator assets (how it works).

What is in this file

An object container file whose header carries the writer schema as JSON, followed by 168,318 binary-encoded customer records in 1,687 blocks. 214 bytes of filler in an extra header metadata entry, which readers ignore, bring the file to the exact size.

Records	168,318
Blocks	1,687, of up to 100 records
Schema	Customer record, 12 fields
Types used	long, string, double, boolean, enum, union, and the uuid and date logical types
Codec	null (not compressed)
Sync marker	16 bytes after every block

First bytes of the file

The first 64 bytes of sample-avro-20mb.avro as a hex dump: offset, bytes, then the same bytes as text. The Avro signature is 4F 62 6A 01.

00000000  4f 62 6a 01 06 16 61 76  72 6f 2e 73 63 68 65 6d |Obj...avro.schem|
00000010  61 d0 0a 7b 22 74 79 70  65 22 3a 22 72 65 63 6f |a..{"type":"reco|
00000020  72 64 22 2c 22 6e 61 6d  65 22 3a 22 43 75 73 74 |rd","name":"Cust|
00000030  6f 6d 65 72 22 2c 22 6e  61 6d 65 73 70 61 63 65 |omer","namespace|

Preview

Avro files cannot be shown in a browser. Download the file and open it in an application that reads Avro, such as Apache Spark, Flink and Hive.

Where 20 MB matters

A 20,971,520-byte file: right at the default attachment limit of Outlook, and just under the 25 MB ceilings of Gmail and GitHub web uploads. These are the default limits a file of this size is useful for testing:

System	Limit	Note
Microsoft Outlook	20 MB of attachments by default for internet mail accounts	This file is right at the limit; add a second attachment and it is exceeded.
Gmail	25 MB per message	Under the limit, although email encoding adds about a third in transit.
GitHub web uploads	25 MiB per file added through the browser	Accepted. Pushing with Git allows larger files.
Cloudflare Pages assets	25 MiB per file	The largest round size that can be served as a static asset.
Amazon API Gateway	10 MB payload	Rejected; the upload has to go directly to object storage.
ASP.NET Core (Kestrel)	About 28.6 MB request body by default	Accepted with room for the multipart overhead.

All 20 MB sample files

Use this file for

Measuring download speed from your own server or CDN
Load-testing readers with many blocks
Testing ingestion jobs and bulk loaders

Testing notes for Avro

No media type is registered for Avro, so files arrive labelled application/octet-stream as often as anything else. Detection has to rely on the four signature bytes.
A logical type is an annotation on a plain type: a date is stored as an int counting days since 1970. A reader that ignores the annotation returns a number where a date was expected.

Avro format reference

Technical details

File name	sample-avro-20mb.avro
Format	Avro (Apache Avro object container file)
Extension	.avro
MIME type	application/avro
Size	20,971,520 bytes (20 MB)
Kind	Binary
Signature	4F 62 6A 01
SHA-256	b32bbbe3c88a5e087648f944080c2bbe0902c9eba57c1bfc486785fca41acca0
Created	2026-10-23
Validation	See the listed size and SHA-256. Small downloads are checked in the browser; verify streamed downloads manually. A hash match does not prove parser compatibility.
Preview	Not available for this file; details only
Source	Generated in your browser by this site's generator; not copied from elsewhere
Licence	Free to use, modify and redistribute (terms)
Category	Data

Check the stated structure and checksum against your application requirements. As with any download, scan the file with your own security tools before opening it. How files are made and checked

Verify your copy

This file is created in your browser, so it has no direct URL for curl or wget. The generator is designed to produce reproducible bytes. After saving, compare the checksum with the SHA-256 value above.

sha256sum sample-avro-20mb.avro     # Linux
shasum -a 256 sample-avro-20mb.avro # macOS

On Windows, run Get-FileHash sample-avro-20mb.avro -Algorithm SHA256 in PowerShell. For scripts and pipelines, save the file once and keep your own copy.

Related files

Questions about this file

Is this file exactly 20 MB?: Yes. It is 20,971,520 bytes, which is 20 MB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
What is inside the 20 MB Avro file?: An object container file whose header carries the writer schema as JSON, followed by 168,318 binary-encoded customer records in 1,687 blocks. 214 bytes of filler in an extra header metadata entry, which readers ignore, bring the file to the exact size.
Are the Avro samples compressed?: No. They use the "null" codec, which every Avro library is required to support, so the records can also be inspected in a hex viewer.

Download