SPI and DICT are central components of the Pix infrastructure, but they serve different functions.
For the user, making a Pix payment seems simple: enter a key or scan a QR code, check the details, enter the amount, and confirm.
Behind the scenes, however, there is a complex financial infrastructure consisting of systems, communication standards, cryptographic mechanisms, and security controls that enable different institutions to exchange information and transfer funds securely.
Two components are essential to understanding this ecosystem: the Instant Payment System (SPI) and the Directory of Transaction Account Identifiers (DICT), both managed and operated by the Central Bank of Brazil (BCB).
DICT allows users to locate the account information associated with a Pix key, while SPI handles the financial settlement of transactions between different institutions. Together, they help make instant payments fast, secure, and available around the clock.
Read on to learn about the role of each party and how they contribute to the operation of Pix.
What are SPI and DICT in Pix?
SPI and DICT are not competing systems. They perform complementary functions within the Pix infrastructure.
To put it simply:
- DICT: links Pix keys to data on transaction accounts and their account holders;
- SPI: settles instant payments between different institutions;
- PI Account: A special-purpose account held at the Central Bank by direct participants in the SPI and used for settlement.
Therefore, a simple way to understand the difference is to think of DICT as helping to identify where the payment should be directed, while SPI actually processes the settlement between the institutions.
What is DICT?
The DICT (Directory of Transaction Account Identifiers) is the Pix database that stores links between addressing keys, transaction accounts, and their account holders.
Currently, the directory supports the following keys: CPF, CNPJ, cell phone number, email address, and EVP, which users refer to as a random key.
When a user enters a Pix key, DICT allows the institution to retrieve the necessary data from the associated account and display the recipient's information for verification before the payment is confirmed.
This system eliminates the need for the payer to know and manually enter the recipient's various bank details.
What information does DICT list?
According to the Central Bank, the database may contain information such as:
- Pix Key;
- Account holder's name;
- CPF or CNPJ;
- Relationship-building institution;
- Agency;
- Account number;
- Account type;
- Dates related to the creation of the key and the opening of the account.
In addition to the query used in the context of payment, DICT supports processes related to key management, including creation, update, deletion, portability, and reclamation, in accordance with the rules applicable to each key type.
There are also specific controls in place to protect this infrastructure. The DICT API uses mutual TLS authentication, and certain requests that include or modify information must be digitally signed. DICT responses are also signed, and their signatures must be validated by API clients.
This shows why integration with DICT involves much more than simply querying a database: there are requirements for authentication, signing, security, and communication control that must be properly implemented by the participating institutions.
What is SPI?
The SPI (Instant Payment System) is the centralized infrastructure used to settle instant payments between different institutions in Brazil.
Operated by the Central Bank since November 2020, the SPI operates on the RTGS (Real-Time Gross Settlement) model. This means that transactions are processed and settled individually, one by one. Once settled, they become irrevocable.
Unlike models in which various transactions are offset for subsequent settlement of net income, in the SPI, settlement occurs on an individual basis.
What is the role of the PI Account?
To understand the SPI, it is also important to understand the Instant Payments Account, or PI Account.
Direct participants in the SPI maintain these special-purpose accounts at the Central Bank. Payments are settled through transactions posted to these accounts.
In addition, the SPI only processes a settlement when there is an available balance in the paying institution’s PI Account. Overdrafts and negative balances are not permitted.
Settlement is conducted in central bank currency and is final, irrevocable, and unconditional. The system operates continuously, 24 hours a day, seven days a week, including holidays.
What is the difference between SPI and DICT?
Although both are part of the Pix infrastructure, their responsibilities are quite different.
| Component | Primary Function |
| DICT | Maintains the links between Pix keys, transactional accounts, and account holders |
| SPI | Processes and settles instant payments between different institutions |
| PI Account | It facilitates the transfer of funds during settlement among direct participants in the SPI |
In practice, therefore, DICT relates to addressing and identification, while SPI relates to financial settlement.
This distinction is especially important for technology, security, architecture, and compliance teams responsible for implementing or maintaining the Pix infrastructure.
How do SPI and DICT participate in a Pix transaction?
In a transaction initiated by a Pix key, the process can be understood, in simple terms, through the following steps:
1. The payer provides the Pix key
The user enters the recipient's CPF, CNPJ, phone number, email address, or random code.
2. The institution consults the DICT
The payer's PSP looks up the corresponding link and retrieves the information needed to identify the recipient's account.
The Central Bank itself states that the data returned by DICT allows the payer’s PSP to generate the payment instruction intended for the settlement system.
3. The user checks the data
The recipient's information is displayed for confirmation, helping to simplify the process and reduce the risk of payments being sent to the wrong recipient.
4. The payment instruction is forwarded for processing
After the institution has performed the necessary validations, the transaction is forwarded for processing.
5. The SPI handles the settlement
When a transaction occurs between different institutions and is settled in the SPI, funds are transferred between the corresponding PI accounts.
Payments are processed individually and only if there is a sufficient balance in the paying institution's account.
Thus, different components work together in a coordinated manner so that what appears to be a simple user experience is supported by a robust infrastructure.
Why is cryptographic security essential when integrating with SPI and DICT?
To participate in the Pix ecosystem, institutions must meet the technical and security standards set by the Central Bank.
This involves elements such as digital certificates, authentication, digital signatures, communication security, and proper management of cryptographic keys.
In DICT, for example, communication uses TLS mutual authentication. Requests that include or modify information in the directory must be digitally signed by the participant responsible for sending them, while the responses provided by DICT also include a digital signature that must be validated by the client.
Protecting the private keys used in these processes is particularly critical. Inadequate management can increase risks related to unauthorized access, compromised credentials, and operational downtime.
Therefore, integration with Pix must be planned with a view to not only system connectivity but also the entire lifecycle of the crypto assets involved.
How does PRODIST support integration with SPI and DICT?
PRODIST offers an encryption solution designed for institutions that need to integrate into the Pix ecosystem with security, scalability, and compliance with applicable technical requirements.
The solution includes integration with SPI and DICT, secure TLS communication, and digital signature capabilities, and can be deployed on-premises or in the cloud.
Its capabilities include:
- XML signature for SPI and applicable DICT operations;
- JWS Signature for Dynamic QR Codes;
- HTTP message streaming;
- JWKS formatting of public keys used in dynamic QR codes;
- Microservices with OAuth2 access control;
- Integration with various key protection mechanisms.
One of the key aspects of this architecture is precisely the protection of the cryptographic keys used in the Pix ecosystem.
PRODIST supports PRODIST STS with its own KMS, as well as the option to integrate with HSMs from approved partners, vaults, and cloud-based KMSs. This allows the institution to structure key custody in accordance with its architecture and security requirements.
PRODIST STS also offers features such as role-based access control (RBAC), certificate-based authentication via mTLS, and remote management.
From design to operation: PRODIST offers technology and specialized support
Integration with SPI and DICT does not end once the components become operational.
Technical changes, certificates, crypto assets, availability, and any incidents must be monitored continuously. In critical financial operations, the time required to diagnose and resolve a problem can be just as important as the robustness of the software used.
PRODIST handles everything from architectural design and implementation to the maintenance of the solution in production.
Founded in 1987, the company has been operating in the Brazilian market for 39 years and has been developing solutions used in National Financial System operations since the SPB’s inception in 2002.
In addition to its proprietary technology, PRODIST offers direct, specialized technical support, with a response time of up to 15 minutes during business hours, the option of 24/7 service, and bilingual support in Portuguese and English.
For banks, fintech companies, credit unions, payment institutions, and other organizations that need to operate within the Pix ecosystem, leveraging specialized technology helps reduce implementation complexity and ensures they have a structure in place that meets the security requirements of one of the country’s most important financial infrastructures.
Do you need to integrate your institution with SPI and DICT, or review the cryptographic security of your Pix infrastructure?
Contact PRODIST to learn about solutions for secure integration with the Central Bank’s ecosystem.
FAQ – SPI and DICT on Pix
SPI is the infrastructure used to settle instant payments between different institutions. DICT is the directory that maps Pix keys to the data of the corresponding transaction accounts and account holders.
DICT is responsible for addressing and identifying the accounts linked to Pix keys. SPI handles the financial settlement of transactions between participating institutions.
SPI stands for Instant Payment System. It is the centralized settlement infrastructure for Pix operated by the Central Bank of Brazil.
DICT stands for Directory of Transaction Account Identifiers. It maintains the links between Pix keys, transaction accounts, and their account holders.
DICT accepts CPF, CNPJ, cell phone numbers, email addresses, and EVP, also known as a random key.
The PI Account is a special-purpose account held at the Central Bank by direct participants in the SPI. It is used for the settlement of instant payments.
Certain requests that include or modify information in the DICT must be digitally signed. Responses from the DICT are also digitally signed and must be validated by the client.
PRODIST provides technology for integration with the Pix ecosystem, including digital signatures, secure communication, protection and management of cryptographic keys, and integration with HSMs, KMSs, and vaults, as well as specialized technical support.
