Modernizing passenger information: the alliance of gravitee and kafka serving public transportation

Faced with the growing challenges of mobility and the ever-increasing expectations of travelers, public transport companies find themselves at a decisive crossroads. The obsolescence of many traditional passenger information systems leads to user frustration and complicates operations management for technical teams. In this context, transforming a passenger information system into a modern and agile platform has become a strategic necessity.

This article explores how integrating API Management solutions—such as Gravitee—and adopting an event-driven architecture based on Kafka can revolutionize the delivery of reliable, real-time, and personalized passenger information.

Context and challenges of digital transformation in public transportation

1. A passenger information system at a crossroads

Traditional passenger information systems often rely on heterogeneous, fragmented infrastructures that are difficult to maintain. Historically, these systems aimed solely to broadcast static schedules and announcements across various channels: mobile apps, websites, display boards, etc. This outdated approach no longer meets the demands of a connected population expecting precise, personalized, and instant information.

Imagine a traveler consulting a mobile app, a website, and display boards simultaneously, only to encounter contradictory information. Such inconsistencies cause a loss of trust in the system and degrade service quality. Furthermore, technical teams struggle to integrate new data sources (IoT sensors, ticketing data, social media) and deploy new services in a rigid and fragmented environment.

2. Challenges of the traditional passenger information system

Key obstacles include:

• Information silos: Data circulates within isolated systems, each with its own formats and protocols, making coherent information delivery difficult.
• Multiplicity of channels: Companies must ensure consistency across all touchpoints—mobile apps, websites, public display devices.
• Traveler expectations: Users demand real-time, personalized information accessible within a few clicks. They want to be alerted of disruptions before leaving home and to receive alternative route suggestions.
• Scalability and performance: Systems must handle significant data volumes during peak traffic times without compromising service quality.
• Security and privacy: Handling sensitive data (e.g., personal or geolocation information) requires robust protection and access control mechanisms.

API Management and event-driven architecture: the pillars of transformation

Meeting these challenges requires a comprehensive approach that rethinks the very design of passenger information systems. API Management and event-driven architecture are two key enablers of this transformation.

1. API Management: centralized and secure control of services

API Management involves designing, publishing, securing, and monitoring APIs that enable efficient communication between applications and systems. Gravitee, a French open-core API Management solution, offers major benefits:

• Unified data exposure: Gravitee transforms data from various sources—including Kafka streams—into standardized APIs accessible through a single entry point across all channels.
• Security and access control: By integrating authentication protocols (OAuth 2.0, OpenID Connect) and authorization policies, Gravitee ensures that only authorized entities access sensitive information.
• Monitoring and analytics: Built-in monitoring tools enable real-time API performance tracking, anomaly detection, and data flow optimization.
• Abuse management and rate limiting: Implementing quotas and throttling rules prevents denial-of-service (DDoS) attacks and ensures continuous high-quality service..

2. Kafka : the engine behind event-driven architecture

At the heart of this transformation is event-driven architecture, allowing asynchronous, real-time communication between applications. Kafka, a distributed messaging broker, plays a central role:

• Real-time data collection and distribution: Kafka ingests data from various sources—sensors, ticketing systems, mobile apps—and immediately distributes it to interested consumers.
• Scalability and resilience: Kafka is built to handle massive data volumes while ensuring high availability and fault tolerance.
• System decoupling: Event-driven architecture allows independent operation of producers (event generators) and consumers (applications receiving events), simplifying system evolution and maintenance.

Integrating communication technologies to modernize passenger information

Beyond API Management and Kafka, a smart combination of complementary technologies ensures seamless, channel-specific communication.

1. REST : interface for on-demand queries

REST (Representational State Transfer) uses HTTP to exchange data. In passenger information:

• On-demand queries: Mobile apps or websites use REST APIs to fetch schedules, route searches, or purchase tickets.
• Ease of integration: REST APIs simplify data integration across diverse applications, ensuring consistent information delivery.
• Synergy with real-time streams: REST complements real-time technologies like SSE for continuous updates.

2. SSE (Server-Sent Events) : continuous update streaming

SSE technology allows servers to push continuous updates to clients subscribed to an event stream:

• Real-time notifications: Immediate delivery of updates (delays, incidents, route changes) to subscribers.
• Enhanced user experience: Dynamic, real-time information without manual refreshes in mobile apps and web interfaces.
• Easy integration: Seamless integration into web applications for cohesive ecosystems.

3. WebSocket: enabling interactive, bidirectional communication

While SSEs provide one-way data streaming, WebSocket establishes a two-way, persistent connection between client and server:

• Instant interaction with chatbots: Real-time messaging for chatbot interactions ensures smooth and responsive communication.
• Rich interactive applications: Supports dynamic needs like personalized notifications or crisis communication.
• Complementary to SSE: SSE handles steady information updates; WebSocket manages interactive exchanges.

Concrete use cases and interaction scenarios

To illustrate the impact of this transformation, let’s examine some concrete scenarios of interaction between users and the modernized passenger information system.

1. The smart mobile application

Imagine a user planning their trip to work:

• Route search: The mobile application sends a REST request to obtain optimal schedules and routes based on the user's preferences.
• Subscription to updates: Once the route is chosen, the application subscribes to an SSE stream, allowing it to receive real-time updates on traffic and possible disruptions.
• Responsiveness in case of disruption: In the event of a delay or incident reported via Kafka, the application immediately displays a notification, suggests an alternative route, and informs the user of any modified connections.
• Interaction with the user: If the user wishes to receive personalized advice or report a problem, they can interact with a chatbot powered by WebSocket, thus ensuring an instant and interactive response.
• Integrated payment: Through secure APIs exposed by Gravitee, the user can purchase their transport ticket directly from the application, thereby simplifying the overall experience.

2. Dynamic display panels

Display panels at train stations or bus stops are transforming into true intelligent dashboards:

• Continuous information stream: Subscribed to SSE streams, the panels receive real-time schedule updates and disruption alerts.
• Contextual display: Depending on the time and ongoing events, the panel can highlight specific information, such as major delays or recommended alternative routes.
• Interaction with other systems: These panels can also interact with traffic management systems to adjust displays based on passenger density and information flow throughout the network.

3. The conversational chatbot

The use of chatbots and generative AI provides personalized and interactive support to travelers:

• Discussion interface: The user engages in a conversation via a chatbot integrated into the mobile application or the website to obtain information about their trip.
• Real-time responses: Thanks to WebSocket, the chatbot can provide instant and tailored responses while proactively alerting the user in case of changes to their itinerary.
• Personalization of alerts: Generative AI also proposes to subscribe the user to personalized notifications, adapted to their frequent routes and preferences.

Security, governance, and monetization

Modernizing a passenger information system is not limited to improving the user experience. It also relies on rigorous management of security and data governance, essential elements for establishing a climate of trust.

1. Strengthened authentication and authorization

Gravitee integrates perfectly with identity providers (OAuth 2.0, OpenID Connect) to ensure that only authorized users access sensitive information:

• Controlling API access: API access is governed by a subscription system. Depending on their exposure models—open data, restricted, or private—subscription requests can be automatically accepted or go through an approval process.
• Managing permissions: Access to each API resource and operation can be finely configured to restrict access based on roles and permissions, ensuring that data is accessible only to authorized persons.
• Encrypting and protecting communications: Encryption of communications between clients (applications, websites, panels, chatbots) and servers (API Gateway, Kafka) ensures effective protection against any interception or tampering of data.

2. Abuse prevention and traffic control

Several mechanisms are put in place to avoid abusive uses that could compromise system performance:

• Usage limitation: Strict policies limiting the number of requests or the rate per user and per application prevent denial-of-service (DDoS) attacks and excessive usage.
• Detection of suspicious activity: Monitoring tools quickly detect anomalies, such as an unusual traffic spike, enabling real-time reaction.

3. Proactive monitoring and feedback

Data analysis and continuous monitoring offer several benefits:

• Performance optimization: Monitoring tools integrated with Gravitee help identify bottlenecks and optimize API throughput.
• Predictive maintenance: Real-time analysis of event flows helps detect potential failures before they impact the user experience.
• Continuous improvement: Collecting data on API usage helps adjust and improve the platform based on feedback from users and technical teams.

4. Data monetization and value enhancement

Digital transformation also paves the way for new economic opportunities for transport operators:

• Premium APIs and subscriptions: By opening access to certain data through standardized APIs, operators can offer premium services to third parties, developers, or companies wishing to integrate enriched data. Subscription or pay-per-use models can thus be implemented.
• Strategic partnerships and data licensing: Building an open ecosystem fosters collaboration with digital and mobility players, generating additional revenue through partnerships or data licensing.
• Data analysis and value creation: Data flows collected via Kafka and analyzed using advanced tools can be monetized in the form of reports or predictive analyses, marketable to organizations or companies interested in performance and traffic indicators.

Concrete benefits and outcomes for public transport operators

Adopting a modern platform based on API Management and event-driven architecture offers many benefits for public transport companies.

1. Improvement of the passenger experience

Users benefit from real-time, consistent, and personalized information:

• Responsiveness: Immediate alerts on disruptions and schedule updates allow travelers to adjust their itineraries with peace of mind.
• Multichannel approach: Unifying information across all platforms (applications, websites, display panels, chatbots) guarantees a consistent and reliable experience.
• Personalization: Thanks to secure APIs, each user can access services tailored to their needs (personalized alerts, custom itineraries, promotional offers).

2. Optimization of operational efficiency

For operators, this transformation results in:

• Reduction of information silos: Centralized data management facilitates the management and integration of new information sources.
• Increased scalability: The ability to manage traffic peaks and process large volumes of data helps maintain optimal service quality even during periods of high demand.
• Simplified maintenance: A decoupled and modular system is easier to update, monitor, and evolve, thus reducing long-term operating costs.

3. Security, governance, and economic opportunities

• Protection of sensitive data: Authentication and encryption mechanisms ensure the confidentiality of information.
• Abuse prevention: Quotas and rate limitations guarantee system stability.
• Data monetization: Opening APIs and leveraging data offer new revenue streams and encourage strategic partnerships.

4. Innovation and agility

The architecture based on Kafka and Gravitee API Management paves the way for continuous innovation:

• Easy integration of new features: The flexibility of the architecture allows new services to be quickly added (e.g., integration of IoT sensors to monitor real-time bus occupancy or infrastructure conditions).
• Adaptability to market changes: A scalable platform enables operators to stay competitive and meet the evolving expectations of travelers, such as real-time information and personalized services.