API Security Engineer
API Security Engineers specialise in identifying, communicating, and remediating security vulnerabilities in API surfaces. Their work spans from threat modelling API endpoints and writing security findings reports to explaining OAuth 2.0 grant type choices to developers and presenting API security posture to compliance teams. This path covers the authoritative vocabulary needed to discuss API authentication, authorisation, and attack surface management in technical and cross-functional settings.
Topics covered
- OWASP API Top 10
- JWT & token security
- OAuth 2.0 & PKCE
- Rate limiting algorithms
- mTLS vs API keys
- API threat modelling
Vocabulary spotlight
4 terms every API Security Engineer should know in English:
Broken Object Level Authorisation — the top OWASP API vulnerability, where an API endpoint fails to verify that the requesting user is authorised to access a specific resource object
"The BOLA finding showed that any authenticated user could access any invoice by simply changing the ID in the URL parameter."
A JWT vulnerability where an attacker modifies the token header to set the algorithm to "none", causing servers that accept unsigned tokens to bypass signature verification entirely
"The penetration test confirmed the alg:none attack was possible — the server was trusting the algorithm specified in the token header rather than enforcing it server-side."
A rate limiting algorithm where tokens accumulate in a bucket at a fixed rate up to a maximum capacity; each request consumes one token, allowing burst traffic up to the bucket's capacity
"We use a token bucket at the API gateway with a refill rate of 100 req/s and a burst capacity of 500 — legitimate clients can absorb traffic spikes."
Mutual Transport Layer Security — a TLS configuration where both client and server present cryptographic certificates for bidirectional authentication; each party verifies the other's identity
"For service-to-service API calls within the cluster, we require mTLS — no service can call the payment API without presenting a valid SPIFFE certificate."
📚 Vocabulary Reference
Key terms organised by category for API Security Engineers:
OWASP API Top 10
JWT & Token Security
OAuth 2.0 & Auth
API Protection Controls
Recommended exercises
Real-world scenarios you'll practise
- Explaining BOLA and the difference from BFLA (Broken Function Level Authorisation) to a backend team before a security sprint
- Writing a security finding report section on JWT algorithm confusion vulnerabilities for a penetration test report
- Presenting API security posture to a compliance officer: framing OWASP API Top 10 coverage and remediation status
- Recommending mTLS vs API key authentication for a new inter-service API to an architecture review board
Recommended reading
Frequently Asked Questions
What English skills do API Security Engineers most need to improve?+
API Security Engineers most commonly need to improve: technical vocabulary (the correct English terms for domain concepts), collocation accuracy (using the right verb for each action), written communication (bug reports, PR descriptions, technical docs), and spoken communication for standups, code reviews, and stakeholder meetings.
How long does the API Security Engineer learning path take?+
The API Security Engineer learning path contains 20–40 hours of material studied comprehensively. Most learners focus on the highest-priority modules first and return to the rest over time. Spending 30 minutes per day for 4–6 weeks produces noticeable improvement in workplace English.
What vocabulary should a API Security Engineer prioritise first?+
Start with the vocabulary that appears most in your daily work — terms you read in documentation, use in commit messages, and hear in meetings. The API Security Engineer path begins with the most frequent vocabulary clusters before moving to advanced communication patterns.
Are there interview exercises for API Security Engineer roles?+
Yes. The API Security Engineer path includes role-specific interview question modules with model answers and key phrases — the actual questions interviewers ask and the vocabulary needed to answer them fluently. There is also a dedicated Interview Practice hub for general interview skills.
Does this path include pronunciation help?+
Yes. The path links to pronunciation exercises for the technical terms most commonly mispronounced in this domain. The Pronunciation hub includes drills for acronyms, silent letters, word stress, and minimal pairs — all in IT context.
What are the most common English mistakes API Security Engineers make?+
The most common mistakes: incorrect collocations (using the wrong verb with a technical noun), false friends from L1, tense errors when narrating past incidents or walkthroughs, and using overly formal or overly casual register in written communication.
How do I improve my English for code reviews?+
Learn the standard code review collocations: approve a PR, request changes, leave a nit, address feedback, block a merge, resolve a conversation. Use hedging language for suggestions: "This might be cleaner as…", "Have you considered…?". The Collocations section includes a dedicated Code Review set.
Can I use this path alongside my daily work?+
Yes — the path is designed for working professionals. Each exercise set takes 10–15 minutes. The most effective approach is to study a vocabulary module before a meeting or task where you'll use that vocabulary, then practise immediately after. Context-linked practice produces much faster retention.
Is the content free?+
Yes, completely free. No registration required, no payment, no time limit. All vocabulary modules, exercises, glossary entries, and learning path guides are open access.
How do I track my progress through this path?+
Progress is tracked in your browser's local storage — completed exercise sets are marked with a checkmark when you return. No account is needed. You can bookmark specific modules and use the exercises overview to see which sets you've completed.