Doesn't work for the other 125 encoded characters that are numerically seven, as defined in the Unicode Character Database:

https://www.unicode.org/Public/17.0.0/ucd/extracted/DerivedN...

(Viewable / copy-able version: https://pastebin.com/fNRv3wD6)

Well then, I won’t be a paying customer then.

You were going to pay for a joke site that checks if a number is seven?

I should mention that unicode.org has a "Unicode Set" query tool so no one gets swindled by a similar service ;)

https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%...

I was almost sure that they do it client-side for a joke, but if you check the browser console, you can see that they actually make a request! You can even make the same request with curl and it works!

Although, making an HTTP request manually is quite inconvenient, so I'm waiting for Python SDK.

Heads up OP: I’m trying to get a pro license but your checkout flow is borked. Probably should fix ASAP before missing out on HN front page traffic.

I misread this as "is even" and was shocked that 46 returned false

I think that's part of the joke. iseven is a real, non-joke package.

With 250k weekly downloads. That is no joke.

With a dependency on is-odd (which in turn has a dependency on is-number)

250k developers collectively decided math needed an API call.

Enterprise looks promising, but before I take this to upper management: How many sevens of uptime are we talking?

> 77.7% uptime SLA

looks like one 7

Seven Sigma is not all it's cut out to be.

that's at least 3

77.7 is generous. I've seen that SLA hit 3am on a Tuesday.

Vulnerable to a distillation attack, unfortunately not much of a moat.

7.0000000000000001 evaluates to true.

It's an inclusive app.

We hit this at work. Had to use Number.EPSILON comparisons instead of strict equality.

As does 6.9999999999999999.

> 77.7% uptime SLA

Giving GitHub a run for its money, I see.

Bug report: I tried 6.999999̅ and got false. So there's some nonstandard model of the reals being leveraged here.

Bug report: I entered 3 + 4 and did not get a kinda or true.

This app is ngmi

Well the all only has 77.7% uptime maybe it just returns wrong things while it’s down, that’s probably it. Try upgrading to Enterprise that’ll probably fix it.

BTW: For a tool that actually legitimately does this, look at Semgrep. Their playground example literally assigns 1 to a variable x, after which searching for "2" finds the expression "1 + x" in the code: https://semgrep.dev/playground/s/5rKgj

I would have expected something other than false for "se7en".

Similar report here:

70/10, 7.1-0.1 and srqt(49) also do not return true.

Is there a published SLA for the free version?

I think everyone has moved on to iseight

00000111 also came back false

no Roman numeral support either

This SaaS actually will be replaced with an in house vibecoded solution.

That documentation is woefully inadequate. It provides only one example request, and then it shows two separate responses, and it doesn't make clear which one is associated with the request. It doesn't even describe the individual request fields, nor does it provide any response codes or a list of error codes/messages. How am I supposed to develop with this?

I do, however, appreciate the seven figure SLA. My service requires at least five nines of uptime, and seven figures is definitely more than five.

Seven figures is indeed more than five figures. Too bad they're all 7s.

7x7=49 > 45=5*9.

Ldo.

Very similar to https://isevenapi.xyz/

Even down to injecting an ad into the response as a joke.

complaint: someone entered "seven" and it crashed my entire infrastructure because the output returned a non standard 'kinda'.

JSONQ supports quantum-aware booleans. Is there a reason you’re still using classical JSON parsing in 2026?

Needs an Agent skill! Gotta be more modern :)

Reminds me of https://five.js.org/

Apparently “seven” is only kinda seven. I would argue that seven is seven!

Got to love that "kinda" is now a JSON bool value!

I can use this as a random number generator; at least it's not nine.

It's just as random as any other number!

It hallucinates 6.9999999999999996 to be seven.

I wanted to subscribe and I can't! How do you expect to make any money if that doesn't work?!!1

No other numbers were harmed in the making of this API.

But their feeling hurts, especially primes.

Did not work, did not recognise 'VII' as seven.

This Is Seven as a Service.

No, this is the test harness for Seven as a Service.

I like how you spent $10 for the domain for this. :)

Honestly $10 is nothing. We've wasted more on a single EC2 instance left running.

10? That seems about $3 too much!

The cheapest domain purchase can be made from CloudFlare. They are selling at ICANN's minimum fee. Which is $10...

I will vibe code my way out of poverty:

Does this have an MCP server?

+1. OP is clearly not read for the Agentic Era

Is this SOC2 compliant?

Does not work for Nw==

TIL 6+1 is not seven.

We wanted to subscribe to the enterprise plan, but unfortunately:

- No Soc-2 compliance

- No sso support.

We asked if we could host on-prem or even byoc but that seems an impossible dream.

Smh

Oh, come on people. You don't need a cloud service for this. Just use the is-seven NPM package.

$ du -sh node_modules/

371M node_modules/

needs an MCP.

Eh, more better than Prolog.