Design a customer journey intelligence platform
PremiumData pipelineMedium
- Event driven
- Olap
- Stream processing
Quick answer
This data pipeline interview question asks you to design a customer journey intelligence platform. Aim for a design that moves data from sources to consumers reliably and on time, then explain ingestion, processing, storage and trade-offs. Interviewers want to see how you handle volume, late or bad data and failures along the way.
The problem
Design a Distributed Customer Journey Intelligence Platform. Modern digital businesses use this platform to track end-to-end customer behavior across marketing campaigns, public websites, mobile apps, and backend support systems.
Customers often interact anonymously across multiple devices before finally creating an account or logging in. Your platform must ingest massive streams of disjointed telemetry, perform real-time "identity stitching" to link anonymous session IDs to known user profiles, and reconstruct continuous, chronological customer journeys. Business analysts will use the platform to run complex, multi-step funnel queries (e.g., "Users who clicked Ad A -> browsed product on Mobile -> purchased on Web -> opened a Support Ticket").
What must a customer journey intelligence platform do?
- Event Ingestion: Provide a highly available API to accept telemetry from web, mobile, and backend server integrations.
- Identity Resolution: Dynamically link anonymous events (e.g., Device ID, Cookie) to known user entities (e.g., User ID, Email) as soon as an authentication event is detected.
What scale should you design for?
Use these numbers in your estimates.
The scale numbers unlock with this questionUnlock
Key concepts
- Event driven
- Olap
- Stream processing
- Identity resolution
- Analytics
How you’ll practise
- Requirements
- Data volume
- Ingestion
- Storage and processing
- Serving and freshness
- Wrap-up
Lala, personalized to you, gives a hint when you ask and reviews your design when you are ready.
What do interviewers look for?
In any data pipeline design round.
- Clarifies sources, consumers and freshness needs
- Chooses batch, streaming or both with reasons
- Handles late, duplicate and malformed records
- Makes each stage safe to retry
- Explains storage formats and partitioning
- Plans monitoring, backfills and data quality checks
Questions people ask about this interview question
- Which design type is this question?
- It is a data pipeline question. You design a customer journey intelligence platform and explain your choices the way you would in an interview.
- Is this question asked at entry level?
- It is marked Medium. Entry-level engineers can practise it, but it expects you to reason about requirements and trade-offs, not only list components.
- What should I cover first?
- Start with the data sources, the consumers and how fresh the data must be. Agree on scope with the interviewer before you design anything.
- Can I practise it for free?
- It is a premium question. Sign up and unlock it once for 10 credits; it then stays unlocked. When you finish, Lala, your personalized AI mentor, can review your design for 30 credits.
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Updated · Written by the SevyDevy team