What does API stand for?
API stands for Application Programming Interface. The interface programs use to talk to each other. For an analyst, APIs are both an attack surface (broken authorization, excessive data exposure) and how tools such as SIEM, SOAR and threat intelligence platforms are wired together.
An API is a defined way for one program to ask another for data or actions. A web API exposes endpoints: a client sends a request, usually over HTTPS with a key or token that identifies it, and gets a structured answer, commonly JSON. Security tools use APIs to exchange alerts and trigger actions, and network devices are configured through them. The same openness is the risk: an endpoint that checks who you are but not what you are allowed to see leaks other people's data.
API in practice: an example
A SOAR playbook receives an alert, calls the firewall's API with an access token and adds an address to the block list. No one logs in to the firewall, and the firewall's log shows which token made the change and when.
What API is confused with
API vs SDK: what is the difference?
An API is the interface itself: the list of requests a service accepts. An SDK is a toolkit, libraries and samples, that makes that API easier to call from a particular programming language.
API vs webhook: what is the difference?
With an API the client asks when it wants something. A webhook reverses the direction: the service calls your URL when an event happens.
Which exams cover API?
API is on the official CompTIA acronym list for two of the four exams covered here.
- CySA+ CS0-004: 1.1, 1.5 (Security Operations).
- Network+ N10-009: 3.0 (Network Operations).
Each number is a CompTIA exam objective and the name in brackets is its domain. The exam puts the term in a scenario; it does not ask you to recite the expansion.
Check yourself: two practice questions
Written by CertSprint for this page. They are not taken from any exam.
1. An API returns any customer's invoice when the invoice number in the URL is changed, as long as the caller is signed in. Which control is missing?
- Transport encryption
- An authorization check on each object
- A longer API key
- Rate limiting
Show the answer
B. An authorization check on each object. The caller is authenticated, but the API never checks that this user owns that invoice. Encryption, key length and rate limits do not decide who may read which record.
2. A script that calls a vendor API suddenly fails with errors saying too many requests were sent. What is the API enforcing?
- Rate limiting
- Certificate pinning
- Port security
- Input validation
Show the answer
A. Rate limiting. Rate limiting caps how many calls a client may make in a period, to protect the service from overload and abuse. The fix is to slow down or batch the requests.
Sources: NIST glossary: application programming interface; OWASP API Security Top 10. The acronym and its expansion come from CompTIA's official acronym lists, linked from each exam glossary above. The explanation, example and questions are CertSprint's own, checked against these sources on 11 November 2026.