APIs

Question 1

400 Cause

Answer 1

Bad request - invalid request syntax, missing params, incorrect data format

Question 2

400 Resolution

Answer 2

Check params, check body of data sent (Content-Type)

Question 3

401 Cause

Answer 3

Unauthorized: Missing or invalid auth credentials

Question 4

401 Resolution

Answer 4

Check API Token (renew token?), service account key, verify auth method (Bearer token, basic auth)

Question 5

403 Cause

Answer 5

Forbidden: User or app doesn’t have permission to access requested resource

Question 6

403 Resolution

Answer 6

Confirm API key has necessary permissions, check for RBAC issues, Verify your IP address is whitelisted

Question 7

404 Cause

Answer 7

Not Found: Requested resource or endpoint doesn’t exist

Question 8

404 Resolution

Answer 8

check URL endpoint and port, ensure correct environment, confirm path exists

Question 9

405 Cause

Answer 9

Method Not Allowed: HTTP method is not allowed for the endpoint

Question 10

405 Resolution

Answer 10

Check the method being sent to endpoint. Is URL allowed by CORS?

Question 11

408 Cause

Answer 11

Request Timeout: Server took too long to process the request

Question 12

408 Resolution

Answer 12

Optimize request payload, check server’s performance, increase timeout value

Question 13

429 Cause

Answer 13

Too Many Requests: API rate limit has been exceeded

Question 14

429 Resolution

Answer 14

Implement rate-limiting logic, get higher limit

Question 15

500 Cause

Answer 15

Internal Server Error: server-side error

Question 16

500 Resolution

Answer 16

Port occupied, backend api or db req sent back an error, check logs of server

Question 17

502 Cause

Answer 17

Bad Gateway: server acting as a gateway received invalid response from upstream server

Question 18

502 Resolution

Answer 18

Check queries, API reqs

Question 19

503 Cause

Answer 19

Service Unavailable: Server is overloaded or undergoing maintenance

Question 20

504 Cause

Answer 20

Gateway Timeout: Upstream server did not respond in time

Question 21

CORS Error

Answer 21

Cross-Origin Resource Sharing: Browser blocked request due to mismatch in server’s CORS policy.

Question 22

CORS Resolution

Answer 22

Add client’s URL to server’s allowedOrigins list
Verify Access-Control-Allow-Origin header on the server

Question 23

JSON Parsing Error Cause

Answer 23

Invalid JSON response or request payload

Question 24

JSON Parsing Error Resolution

Answer 24

Make sure valid JSON is being sent as payload and as response