I simply want to know if my client gives me his crypto website link to put on my website. Is it considered haram or halal?
Opinion of scholars on crypto is divided. Many scholars are on wait and watch mode. As Jammooly has presented above, fiqh council of North America has permitted it with some caveats.
Since you are putting advertising links, I don't think there should be a problem.
If you are thinking of investing, then be careful. Halal does not mean recommended. Compared with other investments - it is one of the most volatile. Invest in it with a fraction of your money, if your risk tolerance is high.
There are many cryptos out there and each one has a white paper that states their purpose and objectives. Cryptos are a form of currency and are often times used as an investment, so the same Islamic rulings that apply to regular fiat currencies such as the USD also apply to Cryptos.
The Fiqh Council of North America views that Bitcoins (cryptos) shall be treated with the same Islamic rulings that apply to all fiat currencies. This includes but is not limited to the following:
- All the rulings of ribā will apply to Bitcoins, as they do to fiat currencies.
- Exchanging Bitcoins for other cryptocurrencies, or for fiat currency, must be done as a spot-trade at the current rate of exchange.
- Purchasing and trading in Bitcoins for the sake of investment is permissible.
- Zakāt will be due on Bitcoin investments if an Islamic year has passed and it is more than the niṣāb amount.
- Obtaining Bitcoins from another person in an impermissible, illegal or deceitful manner is sinful, as is the case with fiat money.
- It is permissible to mine Bitcoins and to be paid for one’s efforts in doing so, even if the payment is in the form of Bitcoins itself.
So promoting crypto links is not haram but, for example, if this certain crypto is used/advertised primarily for something haram such as gambling, then you should not promote it.