PeSIT is a file transfer protocol originally created by the French Interbank Teleclearing System Economic Interest Grouping (GSIT) to facilitate reliable and secure data exchanges in the financial sector. It was designed to meet the high standards of French and European banking institutions, with built-in support for session control, integrity verification and transmission error handling.
The protocol operates in client-server mode and supports both synchronous and asynchronous transfers. PeSIT allows for file compression, checkpoint restart and detailed logging, which makes it suitable for environments that require high levels of data reliability and auditability. Though its use is largely concentrated in France and specific European markets, PeSIT remains relevant in financial networks that require consistent message handling and guaranteed delivery. It’s sometimes integrated into managed file transfer (MFT) solutions to meet the specific needs of legacy financial infrastructure.
Core features of the PeSIT protocol
Key features of the PeSIT protocol include:
- Built-in restart capability for interrupted transfers to avoid data loss
- Configurable compression options to reduce transfer time and bandwidth use
- Detailed logging and transfer tracing to support audit requirements
- Structured session control with explicit negotiation of transfer parameters
- Support for both binary and text file types with defined transfer modes
- Transfer of file information without using file names or directories (using a virtual file identifier)
Organizations can use these capabilities to maintain data integrity and reliability in their file exchange workflows while maintaining strict consistency and recoverability.
How the PeSIT protocol works
PeSIT operates through a structured communication model that allows two systems to initiate, control and complete a file transfer session with strict verification steps. The protocol requires a negotiated session setup before any data is exchanged, which helps define how the transfer will proceed.
Here are the key steps involved in how PeSIT protocol works:
- A connection is established between the sender and receiver, with initial handshake and session negotiation
- Both systems agree on transfer parameters, including file type, compression and integrity settings
- Files are segmented into blocks and sent with error-checking codes to detect transmission faults
- The receiver sends acknowledgments for successfully received blocks or requests retransmission if needed
- Once the transfer is complete, a termination sequence is triggered to cleanly close the session
This process enables controlled, auditable exchanges where each stage of the transfer is confirmed and logged to maintain reliability and traceability.
PeSIT protocol modes
PeSIT supports multiple operational modes to meet different transfer needs across networks and systems. Each mode defines how control and data messages are handled between endpoints, offering flexibility depending on system roles and transfer direction.
The five main PeSIT protocol modes include:
- Automatic mode: Runs predefined transfer jobs without user interaction
- Client mode: The client initiates the connection and controls the transfer session.
- Interactive mode: Allows manual intervention or confirmation before proceeding with transfers
- Reversed mode: Roles are reversed where the server initiates a transfer to the client.
- Server mode: The server listens for incoming connections and responds to file transfer requests.
These modes allow organizations to configure the PeSIT protocol to align with their network architecture, system behavior and automation needs.
PeSIT protocol deployment options
The PeSIT protocol can be deployed across different environments to support both legacy and modern infrastructure. Its deployment options are adaptable to varied system requirements, depending on your organization’s architecture and the criticality of its data flows.
Common PeSIT deployment options include:
- DMZ deployment: Isolates external PeSIT connections for added network security
- Hybrid deployments: Combines on-premises systems with cloud-based services using gateways or connectors
- Mainframe integration: Supports file exchange between distributed systems and legacy mainframe platforms
- On-premises servers: Used in regulated environments with strict data residency requirements
- Private network use: Operates within internal WANs for secure file transfers between branch locations
Your organization can use these flexible options to deploy PeSIT where it fits best within its infrastructure while maintaining security and control.
PeSIT protocol FAQs
PeSIT does not include built-in encryption, but it can work with TLS or VPN tunnels to meet security standards.
PeSIT was designed with built-in controls to support secure and reliable file transfers, particularly in environments where data accuracy and traceability are required. It supports session authentication, configurable file integrity checks and detailed logging, which help maintain control over who can send or receive data and what was exchanged.
The protocol’s support for restartable transfers, session monitoring and error detection help prevent incomplete or corrupted files.
PeSIT and SFTP are both file transfer protocols, but they differ in design and use cases. PeSIT was developed specifically for the banking sector and focuses on reliable, auditable transfers with structured session control. SFTP, on the other hand, is built on SSH and is widely adopted across industries for secure file transfer with built-in encryption.
While PeSIT supports features like session restart and detailed transfer negotiation, it does not include encryption by default. SFTP encrypts all data and commands by design, which makes it a preferred option for organizations with general-purpose security needs. PeSIT remains more common in legacy financial systems, while SFTP is used in broader enterprise environments.
Moving from PeSIT to newer protocols like SFTP, FTPS or HTTPS takes careful planning. Organizations must review current workflows and list all system dependencies. Each endpoint must be updated to work with modern standards. Many older systems rely on PeSIT for batch transfers or mainframe links. The migration must consider timing, file types and automation steps.
A typical migration approach includes parallel testing of the new protocol, configuring encryption and access controls and validating data integrity between systems. The use of middleware or gateways can ease the transition by bridging older systems with modern ones while preserving workflow continuity during the migration process.
