Expand the Abbreviation

Application Programming Interface — a set of rules and contracts that allow different software applications to communicate with each other. You may see it in: "We expose a REST API", "the third-party API returns JSON", "rate-limiting on the public API".

Secure Shell — a cryptographic network protocol for operating network services securely over an unsecured network. Most commonly used for remote server login: "SSH into the server", "add your SSH key to authorized_keys".

Object-Relational Mapping — a technique that lets you interact with a database using object-oriented code instead of raw SQL. Examples include SQLAlchemy (Python), Hibernate (Java), ActiveRecord (Ruby), Prisma (Node.js). "We use an ORM to avoid writing raw queries."

Content Delivery Network — a geographically distributed group of servers that work together to provide fast delivery of internet content. "We serve static assets through a CDN", "CDN edge caches the images closest to the user", "cache invalidation on the CDN after each deploy".

Transport Layer Security — a cryptographic protocol that provides end-to-end security for communications over a network. Successor to SSL. "Enforce TLS 1.2 minimum", "TLS termination at the load balancer", "the TLS certificate expired".

Cross-Origin Resource Sharing — a browser mechanism that allows or restricts web applications running at one origin to make requests to a different origin. "CORS headers are missing", "configure CORS to allow our frontend domain", "the CORS preflight request fails".

JSON Web Token — a compact, URL-safe means of representing claims to be transferred between two parties. Pronounced "jot" (not J-W-T). "Sign the JWT with the private key", "check the JWT expiry time", "never store sensitive data in the JWT payload — it is base64-encoded, not encrypted".

Continuous Integration / Continuous Delivery OR Deployment — CI/CD is a combined term. "CD" can legitimately mean either Continuous Delivery (code is always in a deployable state but humans trigger deploys) or Continuous Deployment (every passing CI build is automatically deployed to production). Both expansions are correct; teams define which they mean. CI always means Continuous Integration — automated testing on every commit.

Domain Name System — the internet's phonebook: it translates human-readable domain names (coderslingo.com) into machine-readable IP addresses. "DNS propagation takes up to 48 hours", "check the DNS record with nslookup", "TTL on the DNS entry is set to 300 seconds".

Service Level Agreement — a contract between a service provider and a customer defining the level of service expected. Key related terms: SLO (Service Level Objective — the target within the SLA, e.g. 99.9% uptime) and SLI (Service Level Indicator — the actual measured metric). "We breached the SLA", "the SLO is 99.95% monthly uptime", "latency is the primary SLI for this service".

HyperText Transfer Protocol — the foundation of data communication on the web. HTTP/1.1 (1997), HTTP/2 (2015), HTTP/3 (2022, uses QUIC over UDP). HTTPS adds TLS. "Return a 404 HTTP status", "upgrade to HTTP/2 for multiplexing", "enforce HTTPS redirect".

YAML Ain't Markup Language — a recursive acronym (the "Y" stands for YAML itself). YAML is a human-readable data serialisation format used heavily in config files (Docker Compose, Kubernetes manifests, GitHub Actions workflows, Ansible playbooks). Pronounced "yam-ul". "The GitHub Actions workflow is a YAML file", "Kubernetes uses YAML manifests", "indentation errors in YAML can break the entire config".