Stripe·Software Engineer·Take-home Assignment·Intermediate

Intermediate

Jun 2026

Summary

Stripe take-home for a software engineer role. The problem was a map rendering task involving coordinate data, alternating path colors, and POSTing a combined payload to a render endpoint to get back a PNG. Pretty self-contained but there were a few moving parts that made it less trivial than it looked.

Questions Asked (1)

You're given a JSON file of GPS coordinates for a ride. Render the path on a map with a start marker at the first coordinate, an end marker at the last, and alternating colored segments every 10 coordinates. Then combine that with existing map data, POST the payload to a render endpoint, and save the returned PNG to disk.

API & IntegrationsTechnical Trade-offs

Author's notes

The color alternation tripped me up more than I expected.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and constraints, then outline a modular pipeline: parse the JSON, generate SVG overlays for markers and colored segments, merge with existing map data, POST to the render endpoint, and save the PNG. Emphasize error handling, idempotency, and scalability considerations.

Pro tip: Mention that you would make the segment length and colors configurable, and use a streaming or chunked approach for large coordinate sets to avoid memory issues. Also, discuss how you would handle API failures with retries and exponential backoff.

1. Clarify Requirements and Constraints

Ask about the expected size of the GPS data, the format of existing map data, the render endpoint's API contract, and any performance or security requirements.

2. Design the Data Processing Pipeline

Outline steps to parse the JSON, validate coordinates, and generate visual elements: start/end markers and alternating colored segments every 10 coordinates.

3. Integrate with Existing Map Data

Explain how to combine the generated overlays with existing map data, ensuring coordinate system alignment and proper layering.

4. Handle the Render API Call

Describe constructing the POST payload, sending it to the render endpoint, and handling responses, errors, and retries.

5. Save and Verify the Output

Detail saving the returned PNG to disk, including file naming, directory structure, and validation of the image.

Key Points to Mention

Input validation and error handling for malformed JSON or missing coordinates
Efficient generation of SVG or canvas overlays for large datasets
Coordinate system compatibility between GPS data and existing map data
API contract details: request format, authentication, rate limits, and error codes
Idempotency and retry logic for the render endpoint
File I/O best practices: atomic writes, unique filenames, and cleanup

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.