What Is a DAS Code? Pine IP Firm Practical Guide
Pine IP Firm
October 22, 2025
When filing overseas applications in the United States, Europe, China, and other jurisdictions based on a Korean invention, applicants are often asked by domestic or foreign counsel to provide a "DAS code" or "DAS access code." Clear practical materials explaining what this code is, why it is needed, and how it should be managed are not always easy to find, which can cause confusion.
A small procedural mistake can even result in the loss of priority rights for an invention that required significant time and cost.
This column explains the exact meaning and importance of the DAS code and, based on Pine IP Firm's practical experience, highlights key checkpoints for reducing critical risks caused by small errors.
DAS stands for Digital Access Service. It is a kind of international digital vault for patent documents operated by WIPO, the World Intellectual Property Organization.
In the past, to claim Paris Convention priority in an overseas filing, an applicant had to obtain a paper priority document, or certified copy, from the office of first filing, such as the Korean Intellectual Property Office, and submit it by expensive international mail to the second filing office, such as the USPTO. This process was costly, time-consuming, and exposed documents to loss.
DAS completely replaces this paper-based priority document submission process.
It is a system that allows patent offices to securely exchange priority documents electronically.
The DAS access code is the unique access credential, similar to a password, that authorizes the later filing office to retrieve the application document stored in this digital vault.
This is one of the most common questions. When foreign counsel asks for the DAS code, where should you look?
When Pine IP Firm completes a patent, utility model, or design application with KIPO, the Korean office immediately issues a Filing Number Notification.
Around the middle of this notice, the [Access Code] item is clearly stated. It is usually a four-character combination of numbers and letters A-F.
This code is generated once for the application and can be reused repeatedly when submitting the same priority document in multiple countries, such as the United States, Europe, China, and Japan.
Use of the DAS system is no longer merely optional. In many countries it has become an essential procedure. The practical trends at major patent offices we regularly work with, including KIPO, USPTO, and EPO, are as follows.
The main cause of failed electronic exchange through DAS is not a system error, but incorrect basic data entered by the applicant.
For the later filing office, such as the USPTO, to retrieve documents from WIPO's DAS vault, the following four items must match the information registered with the first filing office, such as KIPO, exactly.
The door opens only when all four keys match. If the application number or date is entered incorrectly, or the DAS code contains a typo, the USPTO will treat the document as not found.
In that case, the priority document may be deemed not submitted by the deadline, resulting in the entire priority claim being denied. This can lead directly to loss of novelty or inventive step and become a reason for patent refusal.
The DAS code is more than a convenient system. It is a core security key for safe and reliable overseas patent filings.
Accurately recording and managing the basic first-filing information and this four-character code can save significant cost and time in proving priority and prevent serious procedural risks.
Pine IP Firm connects DAS code management from the KIPO filing stage through national phase entries and PCT procedures, providing the safest and most efficient execution plan.
Systematic management from the earliest stage reduces later office actions, correction and amendment risks, and unnecessary costs. We will be your trusted partner in protecting valuable intellectual property.
