Errors & Middleware interview questions

15 real Errors & Middleware questions from the FastAPI bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.

1. What is Exception handler?

Mid
  1. A.the parameter used to schedule work that runs after the response is sent, such as sending an email
  2. B.a layer that wraps every request and response, useful for logging, timing, or attaching headers across all endpoints
  3. C.the component that adds cross-origin headers so browsers permit requests from other configured domains
  4. D.a function registered to catch a given exception type globally and convert it into a formatted response
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3. Which statement is correct?

Mid
  1. A.Exception handler — a layer that wraps every request and response, useful for logging, timing, or attaching headers across all endpoints
  2. B.Exception handler — a function registered to catch a given exception type globally and convert it into a formatted response
  3. C.Exception handler — the error raised when incoming data fails schema checks, returned by default as a 422 with details of each invalid field
  4. D.Exception handler — the parameter used to schedule work that runs after the response is sent, such as sending an email
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4. What is Middleware?

Mid
  1. A.the error raised when incoming data fails schema checks, returned by default as a 422 with details of each invalid field
  2. B.a layer that wraps every request and response, useful for logging, timing, or attaching headers across all endpoints
  3. C.the component that adds cross-origin headers so browsers permit requests from other configured domains
  4. D.the parameter used to schedule work that runs after the response is sent, such as sending an email
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5. Which term means: "a layer that wraps every request and response, useful for logging, timing, or attaching headers across all endpoints"?

Mid
  1. A.CORS middleware
  2. B.BackgroundTasks
  3. C.Middleware
  4. D.RequestValidationError
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6. Which statement is correct?

Mid
  1. A.Middleware — the error raised when incoming data fails schema checks, returned by default as a 422 with details of each invalid field
  2. B.Middleware — the component that adds cross-origin headers so browsers permit requests from other configured domains
  3. C.Middleware — a layer that wraps every request and response, useful for logging, timing, or attaching headers across all endpoints
  4. D.Middleware — the parameter used to schedule work that runs after the response is sent, such as sending an email
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7. What is CORS middleware?

Mid
  1. A.a layer that wraps every request and response, useful for logging, timing, or attaching headers across all endpoints
  2. B.the component that adds cross-origin headers so browsers permit requests from other configured domains
  3. C.the parameter used to schedule work that runs after the response is sent, such as sending an email
  4. D.a function registered to catch a given exception type globally and convert it into a formatted response
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9. Which statement is correct?

Mid
  1. A.CORS middleware — the error raised when incoming data fails schema checks, returned by default as a 422 with details of each invalid field
  2. B.CORS middleware — a function registered to catch a given exception type globally and convert it into a formatted response
  3. C.CORS middleware — the component that adds cross-origin headers so browsers permit requests from other configured domains
  4. D.CORS middleware — a layer that wraps every request and response, useful for logging, timing, or attaching headers across all endpoints
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10. What is BackgroundTasks?

Mid
  1. A.a layer that wraps every request and response, useful for logging, timing, or attaching headers across all endpoints
  2. B.the parameter used to schedule work that runs after the response is sent, such as sending an email
  3. C.the component that adds cross-origin headers so browsers permit requests from other configured domains
  4. D.the error raised when incoming data fails schema checks, returned by default as a 422 with details of each invalid field
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12. Which statement is correct?

Mid
  1. A.BackgroundTasks — a layer that wraps every request and response, useful for logging, timing, or attaching headers across all endpoints
  2. B.BackgroundTasks — the error raised when incoming data fails schema checks, returned by default as a 422 with details of each invalid field
  3. C.BackgroundTasks — a function registered to catch a given exception type globally and convert it into a formatted response
  4. D.BackgroundTasks — the parameter used to schedule work that runs after the response is sent, such as sending an email
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13. What is RequestValidationError?

Senior
  1. A.the error raised when incoming data fails schema checks, returned by default as a 422 with details of each invalid field
  2. B.a function registered to catch a given exception type globally and convert it into a formatted response
  3. C.a layer that wraps every request and response, useful for logging, timing, or attaching headers across all endpoints
  4. D.the parameter used to schedule work that runs after the response is sent, such as sending an email
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14. Which term means: "the error raised when incoming data fails schema checks, returned by default as a 422 with details of each invalid field"?

Senior
  1. A.CORS middleware
  2. B.BackgroundTasks
  3. C.RequestValidationError
  4. D.Exception handler
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15. Which statement is correct?

Senior
  1. A.RequestValidationError — the parameter used to schedule work that runs after the response is sent, such as sending an email
  2. B.RequestValidationError — the component that adds cross-origin headers so browsers permit requests from other configured domains
  3. C.RequestValidationError — the error raised when incoming data fails schema checks, returned by default as a 422 with details of each invalid field
  4. D.RequestValidationError — a layer that wraps every request and response, useful for logging, timing, or attaching headers across all endpoints
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