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Design a Donation Service for a 3-Day Charity Campaign
You are tasked with designing an online donation service specifically for a 3-day charity campaign.
Requirements
- Donors can:
- Select a charity campaign (a single campaign lasting 3 days).
- Enter a donation amount and basic donor information.
- Pay using a third-party payment provider (e.g., a card processor).
- Receive a confirmation (and optionally a receipt).
- The system must handle:
- Payment failures (e.g., declines, timeouts, provider errors).
- Retries and idempotency (to prevent double-charging or double-recording donations).
- High traffic spikes (particularly during campaign launches and closing hours).
- Accurate reporting of the total funds raised.
Out of Scope (Optional, clarify with interviewer)
- Fraud detection
- Tax receipts
- Support for multiple charities
- Recurring donations
- Chargebacks
Deliverables
Describe the following aspects of your design:
- APIs and high-level architecture.
- Data model and key flows (covering both happy paths and failure paths).
- How you ensure correctness (e.g., no duplicate transactions) and scalability.
- Observability and operational considerations.
AI interview prep
Core dilemma
Balancing high-volume, idempotent financial transaction processing with external payment provider dependencies and strict data consistency requirements under peak load.
Mid-level signals3
Senior signals3
Red flags4
3 tradeoffs and 3 stress tests locked
Interview prep
Unlock the interviewer X-Ray rubric, tradeoff matrix, stress tests, clarifying questions, and key concepts.
Design a Donation Service for a 3-Day Charity Campaign
You are tasked with designing an online donation service specifically for a 3-day charity campaign.
Requirements
- Donors can:
- Select a charity campaign (a single campaign lasting 3 days).
- Enter a donation amount and basic donor information.
- Pay using a third-party payment provider (e.g., a card processor).
- Receive a confirmation (and optionally a receipt).
- The system must handle:
- Payment failures (e.g., declines, timeouts, provider errors).
- Retries and idempotency (to prevent double-charging or double-recording donations).
- High traffic spikes (particularly during campaign launches and closing hours).
- Accurate reporting of the total funds raised.
Out of Scope (Optional, clarify with interviewer)
- Fraud detection
- Tax receipts
- Support for multiple charities
- Recurring donations
- Chargebacks
Deliverables
Describe the following aspects of your design:
- APIs and high-level architecture.
- Data model and key flows (covering both happy paths and failure paths).
- How you ensure correctness (e.g., no duplicate transactions) and scalability.
- Observability and operational considerations.