It's not clear from your post, have you tried Gumroads API? They have an endpoint for verifying licenses that works nicely.

  curl https://api.gumroad.com/v2/licenses/verify \  -d "product_id=SDGgCnivv6gTTHfVRfUBxQ==" \  -d "license_key=YOUR_CUSTOMERS_LICENSE_KEY" \  -X POST

Example in React/TS:

  const checkLicenseKeyWithGumroad = async (licenseKey: string) => {
  try {
    const isValidLicenseRequest = await axios.post(
      process.env.GUMROAD_VERIFY_URL as string,
      {
        product_id: 'SDGgCnivv6gTTHfVRfUBxQ==',
        license_key: licenseKey?.trim()
      }
    )
    const isValidLicense = isValidLicenseRequest?.data?.success ? true : false
    return isValidLicense
  } catch (error) {
    console.log(`Error checking license key: ${error}`)
    return false
  }

}

For your language issue, you could self-host the platform and only run purchases through Gumroad. This is how I do it.

> For your language issue, you could self-host the platform and only run purchases through Gumroad. This is how I do it

Good advice. Will have a look at this. Thanks!

https://docs.lemonsqueezy.com/help/licensing (I've never used it myself)

Looks good! Thank you

As a current user of LemonSqueezy, I cannot recommend it.

There is also paddle, which has been around for a lot longer: https://developer.paddle.com/classic/api-reference/4c7d88de5...

I looked at paddle initially, but was not too happy with their chat support. The content of the support was great but the response time was about 1 day, which made it difficult for a chat type conversation. In retrospect, I could've tried writing longer messages.

So I was looking for an alternative and found LemonSqueezy. One of the founders actually helped me onboard, which I was very grateful for. At the beginning the support was great, but it has degraded a lot since. If you go to their slack, you would notice many people complaining about issues being unattended to for weeks and months. I've had first hand experience with this too. I suggest you go to their slack and check out the state for yourself.

In contrast, paddle's response time was better and higher quality too. I'm strongly considering switching to paddle at this point.

but do they have similar api for software licensing?

I recently started using it. integration is really easy.

haven't got any sales so I'm just saying how has it been so far.

Long term HN user @ezekg also runs this https://keygen.sh/ if that might suit your needs (i.e. if you want to separate out licensing logic from the payment logic)

Thanks for the shoutout. To be clear -- Keygen doesn't do payment processing (so no MOA), but here to answer any questions.

Highly recommend implementing accounts for your software and licensing through that, as well as making some features of your app online only (server side), even if they don't have to be.

If your software becomes commercially successful it will eventually get cracked and many corps will use that because licensing in an org setting is messy and who wants to ask for software or deal with the red tape?

>also support EUR as a currency.

Doesn't Gumroad support EU (I assume you mean Euro) as a currency?

EU & UK VAT on Gumroad

https://help.gumroad.com/article/10-dealing-with-vat

Yes, Gumroad supports EUR as a currency (partially).

I am looking for alternatives and I am saying that those alternatives also need to support EUR as a currency (some only support USD).m

Btw the article you linked to is about EU VAT handling. That has nothing to do with supporting EUR as a currency.

Okay, got it, and mea culpa, sorry.

Fastspring or Paddle.

FWIW: As a customer/end-user I found Fastspring easy to use.

Steam?