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Stripe·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
May 2026

Summary

Stripe technical screen centered on a map integration problem broken into three parts, all leaning on Python fundamentals and the ability to explain your thinking as you go. Nothing too exotic, but the third sub-task tripped me up more than I expected.

Questions Asked (3)

Q1

Read and parse data from a JSON file using Python's built-in json package.

API & IntegrationsTechnical Trade-offs
Author's notes

Pretty straightforward.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the requirements: file size, error handling, and performance needs. Then demonstrate a clean, idiomatic solution using json.load() for files, with proper context management and exception handling. Finally, discuss trade-offs and potential improvements for production use.

Pro tip: Mention that for large files, json.load() loads the entire file into memory, so you might use ijson or process incrementally if memory is a concern. Also, always specify encoding='utf-8' when opening the file to avoid platform-dependent defaults.

1. Clarify requirements and constraints

Ask about file size, expected structure, error handling needs, and whether the data is trusted. This shows you think about context before coding.

2. Write the basic parsing code

Use a with statement to open the file and json.load() to parse it. Show a minimal working example.

3. Add robust error handling

Wrap the parsing in try-except blocks to catch FileNotFoundError, json.JSONDecodeError, and PermissionError. Explain how you would log or propagate errors.

4. Discuss performance and scalability

Mention that json.load() reads the entire file into memory. For large files, suggest streaming approaches like ijson or line-delimited JSON.

5. Consider security and validation

If the JSON comes from an untrusted source, validate the schema and avoid using eval(). Mention that json.loads() is safe by default.

Key Points to Mention

  • Use json.load() for file objects and json.loads() for strings.
  • Always open files with a context manager (with statement) to ensure proper closure.
  • Handle common exceptions: FileNotFoundError, json.JSONDecodeError, PermissionError.
  • Specify encoding='utf-8' when opening the file to avoid platform inconsistencies.
  • For large files, consider memory usage and streaming alternatives like ijson.
  • Validate the parsed data against expected schema if the source is untrusted.

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

Q2

Make an HTTP GET request to a provided URL using a requests-style library in Python.

API & IntegrationsTechnical Trade-offs
Author's notes

Also basic, but I fumbled slightly explaining error handling.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the requirements: which library (requests vs httpx), error handling, timeouts, and response parsing. Then write a clean, production-ready function that makes the GET request, handles common exceptions, and returns the response. Finally, discuss trade-offs like synchronous vs asynchronous, retries, and idempotency.

Pro tip: Demonstrate awareness of Stripe's API best practices: always set a timeout, use exponential backoff for retries, and handle rate limits (429) gracefully. Mention that GET requests should be idempotent and safe, aligning with REST principles.

1. Clarify requirements

Ask about the expected response format (JSON, text), error handling needs, timeout, and whether retries or async are required. Confirm the library preference (e.g., requests, httpx).

2. Write the basic request

Use the chosen library to perform a GET request with a timeout. For example, with requests: `response = requests.get(url, timeout=5)`. Then call `response.raise_for_status()` to catch HTTP errors.

3. Handle errors and edge cases

Wrap the request in a try-except block to catch exceptions like `requests.exceptions.Timeout`, `ConnectionError`, and `HTTPError`. Consider retry logic with exponential backoff for transient failures.

4. Process the response

Parse the response based on content type (e.g., `response.json()` for JSON). Return the parsed data or handle it as needed. Optionally, log status codes and response times.

5. Discuss trade-offs and improvements

Mention alternatives like using `httpx` for async support, adding retries with `urllib3` or `tenacity`, and considering idempotency keys for safe retries. Highlight the importance of timeouts and rate limit handling.

Key Points to Mention

  • Use of timeout parameter to prevent hanging requests
  • Error handling for network issues and HTTP status codes (4xx, 5xx)
  • Retry logic with exponential backoff for transient errors (e.g., 429, 503)
  • Idempotency of GET requests and safe retries
  • Response parsing (JSON vs text) and content-type handling
  • Trade-offs between synchronous (requests) and asynchronous (httpx, aiohttp) libraries

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

Q3

Parse a provided JSON file describing ride data, then generate map markers and path overlays to produce a rendered map image.

API & IntegrationsSystem DesignAlgorithms & Data Structures
Author's notes

This is where it got interesting.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the requirements: input JSON schema, expected map output format, and any constraints on libraries or performance. Then outline a pipeline: parse and validate the JSON, transform ride data into markers and path overlays, and render the map image using a mapping library or custom drawing. Discuss trade-offs and edge cases like large datasets or invalid coordinates.

Pro tip: Mention that you would validate the JSON schema and handle malformed data gracefully, and consider using a streaming parser for large files to avoid memory issues. Also, discuss how you would test the rendering with unit tests for parsing and visual regression tests for the map output.

1. Clarify Requirements

Ask about the JSON structure, expected map output (format, resolution), and any constraints like performance or library restrictions. Confirm whether the map should be interactive or a static image.

2. Design Data Pipeline

Outline steps to parse JSON, validate data (e.g., coordinates, timestamps), and transform into a normalized format for markers and paths. Consider error handling for missing or invalid fields.

3. Choose Rendering Approach

Decide on a mapping library (e.g., Leaflet, Mapbox) or custom canvas/SVG rendering. Discuss trade-offs: ease of use vs. control, dependencies, and performance for large datasets.

4. Implement Rendering Logic

Describe how to generate markers (e.g., start/end points) and path overlays (e.g., polylines) from the parsed data. Mention coordinate projection and styling options.

5. Handle Edge Cases and Testing

Address edge cases like empty rides, invalid coordinates, or huge files. Explain testing strategy: unit tests for parsing, integration tests for rendering, and visual checks.

Key Points to Mention

  • JSON parsing and schema validation (e.g., using JSON Schema or manual checks)
  • Coordinate systems and map projections (e.g., WGS84 to Web Mercator)
  • Efficient rendering of many markers/paths (e.g., clustering, simplification)
  • Choice of mapping library vs. custom rendering and trade-offs
  • Error handling and graceful degradation for malformed data
  • Testing strategies: unit tests, visual regression, performance benchmarks

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