Webbol: a Minimal Static Web Server Written in Cobol

Posted3 months agoActive3 months ago

simonpure

134 points

51 comments

github.comTechstoryHigh profile

calmpositive

Debate

20/100

CobolProgramming LanguagesWeb Development

Key topics

Cobol

Programming Languages

Web Development

The HN community discusses a GitHub project implementing a minimal static web server in COBOL, sparking conversations about the language's relevance, security, and readability.

Snapshot generated from the HN discussion

Discussion Activity

Very active discussion

First comment

32m

Peak period

0-3h

Avg / period

6.4

Comment distribution51 data points

Loading chart...

Based on 51 loaded comments

Key moments

01Story posted
Oct 3, 2025 at 10:13 AM EDT
3 months ago
Step 01
02First comment
Oct 3, 2025 at 10:44 AM EDT
32m after posting
Step 02
03Peak activity
23 comments in 0-3h
Hottest window of the conversation
Step 03
04Latest activity
Oct 4, 2025 at 9:49 PM EDT
3 months ago
Step 04

Generating AI Summary...

Analyzing up to 500 comments to identify key contributors and discussion patterns

Discussion (51 comments)

Showing 51 comments

nonethewiser

3 months ago

3 replies

It's interesting to see just about every line in the code commented. Makes you re-examine the assumptions made when people say "the code should be self documenting."

Namely, that the code will be read by someone who knows the language. And arguably that the code should be capable of being "self-documenting." Although perhaps people well-versed in COBOL would argue COBOL can be, and I just don't know it.

wrs

3 months ago

2 replies

See commit d9a5e3e, “Added comments to the code to help curious folks understand what each line is doing”.

pmarreck

3 months ago

2 replies

I seem to understand most of it except for this data typing stuff:

    PIC 9(9)V99

and the like. What is PIC?

zoom6628

3 months ago

1 reply

IIRC is means a pictorial definition of a value so the above is a float printable using 12 positions which for maximum value would be as 999999999.99 While a PIC X(10) Means character string length 10. It was defined in era of fixed width fonts and band printers so the max printing width was 132 and one had to know exactly where each character would print. Report writing in COBOL is easy.

ochrist

3 months ago

Almost correct. However, this is not a float but a fixed decimal value with two decimals. The V is not stored but just used to indicate where the decimal sign should be. Source: I've written a lot of COBOL years ago.

tuatoru

3 months ago

PIC is short for PICTURE, which was the original form of the keyword. Picture the number printed this way.

Edit: the numbers in parentheses are repeats. PIC 9(9) means up to 9 digits in the printed representation of the value stored in the variable that has this PIC.

jmsdnns

3 months ago

yep. the comments are for folks who have never tried to read cobol before, which is probably 99% of people looking at the project. this way they can understand a familiar idea expressed in a language that is probably wildly different from what theyre used to.

for example IT IS YELLING AT US THE WHOLE TIME

samus

3 months ago

1 reply

I heard people at a bank claim that COBOL code is basically natural language and thus self-documenting. I almost laughed out at that.

RaftPeople

3 months ago

1 reply

Bank teller: "And how can I help you?"

Customer: "PERFORM 500-DEDUCT-ACCOUNT-BALANCE"

Bank teller: "Ok, great, and how much?"

Customer:

"01 TRANSACTION RECORD

  05 TRANSACTION-AMOUNT PIC 9(9)V99

MOVE 100.00 TO TRANSACTION-AMOUNT"

tuatoru

3 months ago

A future we didn't quite make it into.

CaptainOfCoit

3 months ago

"Namely, that the code will be read by someone who knows the language. " Most of the time I think it depends on the context. If you're writing code as a learning exercise, either for yourself or for others, it makes sense to use comments to expand on what lines actually do.

If you're in the context of a professional environment, where you chose the team, it makes sense to be more dogmatic about it to enforce a better overall architecture, and you can safely assume that the next reader at least knows the language already.

jrmg

3 months ago

2 replies

I know this is a ‘joke’, but it sparked in me actual questions that I am sure some folks here will know the answers to:

What are the security guarantees with writing in COBOL? Like, does COBOL allow out-of-bounds memory access? How does it compare to C or Rust as far as allowing ‘accidental’ security lapses?

evnu

3 months ago

I wondered about that as well while looking into the http handler. I think a missing space between method and path overruns the buffer (haven't tried running it though).

leakycap

3 months ago

> Like, does COBOL allow out-of-bounds memory access?

Modern COBOL compilers will catch this with an error; if you do manage to compile and run, you'll get a runtime error or immediate crash.

> How does it compare to C or Rust as far as allowing ‘accidental’ security lapses?

COBOL has reference modification that can easily be purposefully used to reference memory outside the bound of the original data you target. It isn't memory safe, it's just very restrictive so many errors/misuses get weeded out during compiling.

tuveson

3 months ago

3 replies

People say “pick the best tool for the job” and then refuse to pick COBOL for their COmmon Business Oriented probLems

dardeaup

3 months ago

1 reply

They don't refuse to pick COBOL, they refuse to consider COBOL.

pmontra

3 months ago

They even forget that COBOL could run on their computers and servers.

graemep

3 months ago

2 replies

Why and when is the the "best tool for the job"?

ternaryoperator

3 months ago

It's an ideal language for creating business reports, which is what it was originally designed to do. It has built-in commands for reading randomly or sequentially from a database and it has extensive report-formatting options. It has other application capabilities, of course, but business reporting (especially complex reports) are its sweet spot.

lazerman

3 months ago

Whoosh

jsight

3 months ago

1 reply

That is true for MUMPS too. People overlook what an epic decision they could be making.

slongfield

3 months ago

The big problem with MUMPS is that as the "Massachusetts General Hospital Utility Multi-Programming System", it does not work well for development in other states. There's been some experimentation with using it in Wisconson, but a W is not an M.

john-tells-all

3 months ago

2 replies

I thought I could program in any language. But: that Cobol project makes Assembly language look clean and elegant.

I applaud Jms Dnns! This project really makes you think.

jmsdnns

3 months ago

thank you!

zoom6628

3 months ago

First job out of school was manufacturing systems support in COBOL and finance systems support in Assembler. As someone who has dealt with 40cm deep line flow stacks of source code for both the COBOL is way easier to hold in my brain. YMMV.

neoeno

3 months ago

3 replies

Love to see fixed format mode in use :)

For those who are unaware — you can use COBOL in two modes: free mode and fixed format mode.

Fixed format mode is (afaik) the original, based on punch card affordances, and specifies specific columns for specific purposes:

* The first 6 columns for line numbers

* Column 7 for the indicator character (notably: * for comments as you can see here https://github.com/jmsdnns/webbol/blob/main/file-structs.cpy )

* Column 8-11 for special division markers, though they can extend beyond (visible in this file: https://github.com/jmsdnns/webbol/blob/main/webserver.cbl)

* Columns 12-72 for ordinary COBOL statements

* Columns 73-80 for programmer comments or whatever notes you like

All the columns are undoubtedly a bit taxing to the modern developer and their tools, so 'free mode' which discards all the above is the suggested default.

But, I think fixed mode is very charming, and if you're going to write COBOL in 2025, you may as well try to get the most authentic experience!

rdimartino

3 months ago

1 reply

I liked this too, but interesting that the Makefile uses the `-free` flag for cobc

bombcar

3 months ago

1 reply

I assume fixed is a subset of free? So perhaps a few lines somewhere aren’t perfect.

jmsdnns

3 months ago

the code is similar to fixed format, but the location of the comments gives away that it is actually in free format.

* comments use *> at start of line, though I'm not sure i'll keep that

* indentation is flexible, but i prefer how fixed looks

* no column restrictions

gmueckl

3 months ago

1 reply

Early versions of Fortran also had a fixed column layout, although the columns were different. The only commonality thst I can find right now is ignoring columns 73 to 80 to make space for card sequence numbers.

I never wrote a program on punch cards, but I'd definitely drop card stacks accidentally or get them into a jumble somehow. Having numbered cards and a card sorting machine (radix sort in hardware!) would be extremely helpful then.

pklausler

3 months ago

1 reply

Old-timer tip: take a marker and draw a diagonal line across the top of your card deck, from the column 1 left side edge of the first card to the column 80 right side edge of the last card. When you drop the deck, just reassemble the line.

dmoy

3 months ago

1 reply

Which sorting algorithm do you use when reassembling? Does it work well with "eyeball it and stick it near correct-ish spot and then fiddle with it later"?

sgarland

3 months ago

Depends how much bleed your paper has with your marker, but in general it’s quite accurate to eyeball it. I’ve never used it on punch cards, but I have for large documents.

wrs

3 months ago

Cols 73-80 were sometimes used for sequence numbers so when you spilled your cards on the floor you could run them through the sorting machine.

This may help you get the feel (pick the COBOL card at the top). [0]

For an even more authentic experience, write the program on a coding form first, then give it to an assistant for keypunching. [1]

[0] https://www.masswerk.at/keypunch/

[1] https://www.mainframestechhelp.com/tutorials/cobol/coding-sh...

rdimartino

3 months ago

1 reply

I'd love to learn more about what `CALL "socket"` is doing. CALL is for running subprograms, but it's not clear to me where "socket" is?

I've thought about a COBOL webserver before, but didn't get beyond reading the GnuCOBOL FAQ that mentions it's possible with CGI https://gnucobol.sourceforge.io/faq/gcfaq.html#id1126

I'm definitely going to dig into this project more later. This is very neat!

samus

3 months ago

1 reply

Could simply be the `socket` system call.

jmsdnns

3 months ago

yep, it calls the external c function. same with setsockopt, bind, and listen further down.

tangus

3 months ago

1 reply

In the late 90's I had a girlfriend who worked for a shop that made web pages in COBOL. I thought those were COBOL's death throes, but apparently I was mistaken...

z3ratul163071

3 months ago

that's it. you get the reward for the weirdest gf ever.

ethin

3 months ago

I've always wanted to learn Cobol. So, I of course did what I sometimes do and bought the standard. Of course, it then turned out that the standard used inaccessible diagrams instead of any kind of decently modern syntax notation like EBNF, so I could at most only get scraps from the syntax parts and nothing actually useful. I wasn't entirely sure if even learning it would be worthwhile or be something I would be able to do, but I thought eh, why not give it a go?

GartzenDeHaes

3 months ago

COBOL used to drive some government and business web sites. You could tell because the HTML was output in 100 column fixed width format.

pantulis

3 months ago

Now we are one step closer to fully realize the vision of Cobol on Cogs

http://www.coboloncogs.org/INDEX.HTM

beny23

3 months ago

Love this!!! Any tips for learning cobol?

throwaway-18

3 months ago

My employer has been around 40 nearly 50 years. We still run COBOL for 90% of our business operations. Day-to-day employees work in bluescreens built in RM/COBOL and RM/PANELS.

As recently as the 2010s, we used to emit HTML out of COBOL, but fell short of it directly responding to HTTP requests. Instead, we licensed an RPC layer that sits behind Apache and translates HTTP calls through CGI to a listener on the COBOL side that then invokes COBOL programs. Those programs send back HTML strings through the CGIRPC interface and, well, out comes a webpage in your browser.

We're still using it to serve XML and have turned it into a makeshift web service that helps power a traditional web application.

But, honestly, this is way cooler.

pmarreck

3 months ago

I showed my toddler parts of the original TRON not long ago, and for some reason, reading this reminds me of that lol

andrewshadura

3 months ago

IDENTIFICATION DIVISION. PROGRAM-ID. WEBSERVER.

brightball

3 months ago

Saw a great talk on COBOL this summer at the Carolina Code Conference

https://youtu.be/RM7Q7u0pZyQ