READY · FREE · NOTHING UPLOADED

Mainframe data, made visible.

● RECORD DECODER · customers.dat · FB 71 · CP037ROW 3 OF 3

CUST-ID ..... 100236

CUST-NAME ... LEE CHEN

CUST-BAL .... X'4040404040' ◂ S0C7 RISK

ORDER-COUNT . 0

F1=HelpF7=UpF8=DownF10=CSVF11=JSONon this device

Byte maps, colour-linked hex, annotated JCL and plain-English error codes. Everything runs on your device — free, no sign-in, nothing uploaded.

ENTER ▸ Decode a file Look up a code

10tools for data, JCL and sort

161abend, SQL, CICS and MQ codes

7EBCDIC code pages

0 bytesever sent to a server

Tools

OPTION ===> type a number in the command boxAll tools

01Copybook viewer

Paste a COBOL copybook and see every field's position, length and type.

02Record decoder

Read a mainframe data file with its copybook as a table, CSV or JSON.

03Packed decimal calculator

Turn numbers into packed, zoned or binary hex, and back.

04EBCDIC converter

Convert text to EBCDIC hex and back, in seven code pages.

05Mainframe date converter

Julian YYDDD, CYYDDD, Lilian days and STCK clock values to real dates.

06Block size and space calculator

Best BLKSIZE for your record length and the space a file needs on 3390.

07JCL checker

Find common JCL mistakes and read each statement in plain English.

08JCL generator

Fill in a form to get ready-to-run JCL for everyday jobs.

09DFSORT helper

Build SORT, INCLUDE and OUTREC statements, or explain existing ones.

10COBOL debugger

Step through a COBOL program line by line and watch every field change.

11MainframeKit assistant

Ask in plain words; answers come only from this site's pages.

Error codes, explained

All 161 codes

S0C1 · S0C2 · S0C4

Abend codes36 codes

-805 · -811 · -803

Db2 SQLCODEs40 codes

ASRA · AEXL · ASRB

CICS codes44 codes

2009 · 2016 · 2018

MQ reason codes41 codes

Recently used

kept in this browser only

Tools and codes you open appear here.

Why it is private

Processed on your device

Files and text are read by your browser. There is no server that could receive them.

Blocked by design

The site's security settings forbid these pages from sending data anywhere, so even a bug cannot leak a file.

No accounts, no cookies

Nothing to sign up for and nothing that follows you around.