The term "tax self-certification" does not exist in OKX's official documentation. What you actually need to fill out is Tax Information, centered on your country of tax residence and your TIN (Taxpayer Identification Number). Where and how you fill these in depends on your account's registration region and whether you are an EEA (European Economic Area) user. Non-EEA users usually do not need to proactively "self-certify"; it only needs to be handled when the platform requires an update or a form pops up during the registration process. If you make a mistake, you cannot correct it yourself; you must go through customer support.
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First, Confirm If You Are Required to Fill It Out
OKX's collection of tax information follows a clear region-driven logic. According to DAC8 (EU Crypto-Asset Reporting Framework) rules, EEA users must provide tax information when registering or when required by the platform; failure to do so may result in temporary account restrictions until the information is provided. This applies to users in EEA countries such as Germany, France, Italy, the Netherlands, and Poland.
If you are not an EEA user, OKX currently does not mandate in its public documentation that you proactively fill out a tax self-certification form. The situation for US users is different: starting in 2026, OKX will begin collecting W-9 (for US persons) or W-8 (for non-US persons) forms. Failure to provide them may result in a 24% backup withholding starting January 1, 2027. This is a US tax compliance requirement, separate from the EEA's DAC8 framework.
The situation for Chinese-speaking readers is more varied: users from Mainland China, Hong Kong, and Singapore are subject to different rules. If you were not asked to fill in a TIN when registering for OKX, and you have not received a notification from the platform asking you to update your tax information, then you do not need to proactively look for an entry point. If you have received a notification, follow the path indicated in the notification.
What to Fill in for TIN: Depends on Your Country of Tax Residence
A TIN is not a single, globally unified string of numbers; each country has its own format and name. OKX's DAC8 FAQ lists the TIN formats and how to find them for various EEA countries. Here are a few relevant to Chinese-speaking readers.
Germany: Steueridentifikationsnummer (Steuer-ID), typically 10 to 11 digits, formatted like 99 999 999 999. It can be found on the Einkommensteuerbescheid (income tax assessment), letters from the local tax office, or the annual wage tax statement.
France: Numéro fiscal de référence (NIF), 13 digits, like 1234567890123. It appears on the tax notice (avis d'imposition), letters from DGFiP, and in your personal account on impots.gouv.fr.
Italy: Codice Fiscale, a 16-character alphanumeric code, like MRTMTT91D08F205J. It can be found on the tax card, the back of the electronic identity card, or official communications from the tax authority.
Spain: For individuals, the NIF is 8 digits plus 1 letter, like 12345678A. For foreigners, the NIE is a letter (X/Y/Z or M) plus 7 digits plus a control letter, like X1234567T. It can be found on the ID card, driver's license, or residence permit.
Netherlands: BSN (Burgerservicenummer), 9 digits. Poland: PESEL, 11 digits.
If your country is not within the EEA, OKX's public FAQ does not provide TIN format guidance. In this case, fill in the taxpayer identification number issued by your country's tax authority, using the format shown on your local tax documents.
What to Do If You Don't Have a TIN
OKX's DAC8 FAQ provides a solution: if your country does not issue a TIN, or you have not yet received one, you can usually select "Tax Number Not Available" and provide a reason, such as student status or a recent move. The platform will record this situation to remain compliant.
This option is not an excuse to "just skip it." If you actually have a TIN but select "Not Available," the platform may require further explanation during a later review. If you genuinely do not have one—for example, you have just moved to a new country and have not completed tax registration—selecting this option and stating the reason is reasonable.
How to Correct a Mistake: You Cannot Do It Yourself
This is directly related to the topic of "correcting information." OKX's public help pages state: to update your SSN, TIN, or legal name, you need to go to the Tax Center, then contact customer support via the "Chat with us" button in the notification banner, and the support team will assist with the update. Some regional pages say "Update Profile or Contact OKX Help," but the core process is the same: there is no self-service correction option.
This means you should double-check before submitting. A TIN is a string of numbers or alphanumeric characters; entering one digit incorrectly could result in the platform reporting incorrect information to the tax authority, and correcting it requires manual customer support, with an uncertain processing time. Hypothetical example: you enter one digit short of the 13-digit French NIF, submit it, and only then realize the mistake. You cannot edit it yourself in the Tax Center; you must contact customer support. During the support process, if the reporting deadline arrives, the incorrect information may already have been reported.
A Common Point of Confusion
The term "tax self-certification" can easily be mistaken for "proving that you have already paid your taxes." OKX does not require your tax payment certificate, nor your trading profit and loss calculations. What it requires is your tax identity: which country you are a tax resident of, and what your TIN is. The platform uses this information to report account details to tax authorities under frameworks like DAC8 or the US 1099-DA. It is not calculating your taxes for you, nor is it auditing whether you have paid them.
You do not need to upload tax returns, tax payment certificates, or transaction records to "self-certify." If someone on an unofficial channel asks you to provide these materials to "complete OKX tax self-certification," that is not an OKX process.
Our Recommendation
If you use OKX in an EEA country and have received a request to fill out tax information, fill it out carefully; do not skip it. The consequence of not filling it out is account restriction, not "I'll do it later." The TIN format and where to find it are listed by country in OKX's DAC8 FAQ. First, check your country of tax residence to find the correct number before filling it in. Double-check before submitting, because you cannot change it yourself.
If you are not in the EEA and are not a US taxpayer, OKX does not require you in its public documentation to proactively complete a "tax self-certification." Just wait for a notification from the platform; you do not need to research TIN formats in advance. If you are asked to fill in a TIN on other trading platforms, the logic is similar: you are providing your tax identity, not proof of tax payment.
If you do not yet have an OKX account, when registering with our site's invitation code 24U2795, the referrer field is in the registration form and is optional. The invitation code has no connection to filling out tax information—TIN and tax residence are independent compliance fields and are not affected by referral relationships.
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New user benefit: 20% off trading fees upon registration!！
References
- OKX·Crypto Tax Reporting (DAC8) FAQ (English), page published or updated: 2026-02-24; verified: 2026-10-21.
- OKX·Crypto Tax Reporting (DAC8) FAQ (Traditional Chinese), page published or updated: 2026-02-24; verified: 2026-10-21.
- OKX·Questions fréquentes sur la déclaration fiscale des cryptos (DAC8), page published or updated: 2026-02-24; verified: 2026-10-21.
- OKX·Preguntas frecuentes sobre la declaración fiscal de criptomonedas (DAC8), page published or updated: 2026-02-24; verified: 2026-10-21.
- OKX·How do I manage my tax account and documents?, page published or updated: 2026-08-05; verified: 2026-10-21.
- OKX·How do I manage my tax account and documents? (Poland site), page published or updated: 2026-05-29; verified: 2026-10-21.
- Awaken Tax·OKX 1099-DA Tax Form: What It Means and How to Report It Correctly, page published or updated: no date indicated; verified: 2026-10-21.
