who builds software, and what they call everything.

The Big Three

• product manager PM · "product"

  The person who decides what gets built and why. They talk to customers, look at data, write specs, and prioritize the backlog. They're the one in the room arguing for the user's problem.

  What they doInterviews users. Writes the doc that says "here's the problem, here's the proposed solution, here's how we'll know it worked." Defends scope. Says no to a lot of things.

  Not to be confused withProject manager. Different job. Project managers run timelines and coordinate across teams. Product managers decide what the product should be. Same two letters, very different role. When tech people say "PM" they almost always mean product manager.

  You'll hear"The PM said we're not building that." / "Who's the PM on this?" / "PM-led" vs "engineering-led" company.

• engineer ENG · developer · dev · SWE · "the eng team"

  The people who write the code. Engineer and developer mean the same thing in practice. There is no real distinction. "Software engineer" is the modern resume word; "developer" is the older, slightly more casual word; "coder" is what your parents call them. SWE = Software Engineer.

  What they doTake the spec from the PM and the mockup from the designer, then build the actual thing. Argue about how to build it. Estimate how long it'll take, then take twice as long. Maintain it after it ships.

  Not to be confused withA "developer" in real estate (totally different industry, same word). Also, not every technical person on a team is an engineer. Designers, PMs, and ops people often have technical skills without writing production code.

  You'll hear"Eng pushed back on the deadline." / "We need another engineer." / "The dev team is shipping next week." / "Talk to engineering about feasibility."

• designer product designer · UX · UI · "design"

  The person who decides what the product looks like and how it feels to use. They make the mockups, define the visual system, and worry about whether a button should be 8 or 12 pixels.

  What they doResearch how users actually behave, sketch flows, build mockups in Figma, hand off to engineers, iterate when things don't work. At small companies, one designer does all of it. At big companies, it splits into UX (user experience, the flows) and UI (user interface, the pixels).

  You'll hear"Design is blocking us on the new checkout." / "The PM and designer need to align." / "Who's our designer on this?"

Specializations of Engineer

"Engineer" is a big category. When people talk about which kind of engineer, it's usually one of these:

• frontend engineer FE · "front-end"

  Builds the part users see and click. The website, the app screens, the buttons. Lives in HTML, CSS, JavaScript, and frameworks like React or Vue.

  You'll hear"We need a frontend for the new dashboard." / "Frontend is done, waiting on backend."

• backend engineer BE · "back-end" · server engineer

  Builds the part users don't see. Databases, business logic, the APIs that power everything. The plumbing.

  You'll hear"Backend is the bottleneck." / "We need a backend who knows Postgres."

• full-stack engineer fullstack · FS

  Does both frontend and backend. Common at startups where you can't afford specialists. Senior full-stack engineers are gold because they can ship a whole feature without handoffs.

  You'll hear"We're hiring two full-stack engineers." / "She's full-stack but stronger on backend."

• DevOps / SRE platform · infra · "ops"

  The engineers who keep everything running. Servers, deploys, monitoring, the pipes between systems. They're the reason your app doesn't go down at 3am. SRE = Site Reliability Engineer (the term Google popularized; basically the same job).

  You'll hear"Devops set up the new CI pipeline." / "SRE is on-call this week." / "We need to hire infra."

• AI / ML engineer "the AI team"

  Engineers focused on building with language models, training models, or wiring AI into a product. The newest specialization. At companies built around AI (like a Claude wrapper or a RAG product) the AI engineers and the backend engineers blur together.

  You'll hear"Our AI engineer is prototyping the agent." / "We need someone who's good with LLMs."

Seniority Ladder

All engineering roles have levels. When someone says "she's a Staff engineer" or "we just hired a Principal," this is what they're referencing:

• junior L1, L2, "new grad"

  Just started. 0-2 years experience. Needs guidance on what to build and how to build it.

• mid-level / senior L3, L4, L5

  Can ship a feature end-to-end without hand-holding. Most engineers spend most of their career here. "Senior engineer" is the most common title in tech.

• staff L6, "staff eng"

  The level above senior. Influences technical direction across a team or multiple teams. Often the most senior person who's still writing code daily.

• principal / distinguished L7+

  The rare top of the technical ladder. Shapes architecture across the whole company. The non-manager equivalent of a VP.

Managers & Leadership

• engineering manager EM · "eng manager"

  Manages a team of engineers. Hires, fires, runs 1:1s, removes blockers, owns the team's output. Doesn't usually write production code. The first management rung above engineer.

  You'll hear"Talk to the EM about headcount." / "She's the EM for the platform team."

• tech lead TL · "tech lead manager" (TLM)

  A senior engineer who leads the technical direction of a team but isn't a formal manager. Like a player-coach. At some companies it's an official title, at others it's just "the senior person on the team."

  You'll hear"Who's the tech lead on this?" / "Tech lead reviewed the design."

• CTO Chief Technology Officer

  The most senior engineer in the company. At a startup, often a co-founder who writes code. At a big company, an executive who hasn't touched code in years and runs the whole engineering org.

• VP Engineering VPE

  Runs engineering operations. Hiring, performance, delivery. At startups, the CTO and VPE are sometimes the same person; at bigger companies they split (CTO = technical vision, VPE = engineering execution).

• CPO / Head of Product Chief Product Officer

  The most senior product person. Manages all the PMs. Decides what the company builds.

Supporting Roles

• QA / QE Quality Assurance · Quality Engineer · "test engineer"

  Tests the software before it ships. At modern startups, this often gets folded into the engineering role (engineers write their own tests). At bigger or older companies, QA is its own function.

• data engineer / data scientist DE · DS

  Different jobs, often confused. Data engineer = builds the pipelines that move data around. Data scientist = analyzes the data to answer business questions or build models.

• technical PM TPM · Technical Program Manager

  A project manager (the timelines-and-coordination one) who works inside engineering. Owns the cross-team logistics on big initiatives. Common at large companies, rare at startups.

• developer relations DevRel · DX · developer advocate

  The people who help other developers use a company's product (when the product is something developers build with, like Stripe, Anthropic, Vercel). Half marketing, half engineering. Write tutorials, give talks, hang out on Discord.

  You'll hear"Anthropic's DevRel is great." / "She does developer relations at Stripe."

Code & GitHub

• reporepository
  The folder/project hosted on GitHub. Where the code lives.Where"check the repo," "fork the repo."
• PRPull Request
  A proposed code change someone wants merged into the main project. The unit of code review.Where"I opened a PR for that fix," "review my PR."
• commit
  A saved snapshot of changes.Where"I committed the fix," "revert that commit."
• branch
  A parallel line of development. You work on a branch, then merge it back to main.Where"checkout the feature branch."
• mainalso "master"
  The primary branch. The canonical version of the code that gets deployed.Where"merged to main," "CI is failing on main."
• merge
  Combining a branch into another. The final step of a PR.Where"we'll merge this Friday."

Shipping & Environments

• deploy
  Pushing built code to a live server so users can actually use it.Wherevercel deploy --prod, "the deploy failed."
• prodproduction
  The live environment real users hit. The one you don't break.Where"do NOT test that in prod."
• staging
  A near-production environment for final testing before the real thing.Where"works on staging, broken in prod."
• CI/CDContinuous Integration / Deployment
  The automated pipeline that tests your code and ships it on every change. The "robots do the boring part" layer.WhereGitHub Actions, Vercel deploy logs.
• build
  Compiling source code into runnable form. "Build failed" = the compilation step broke.Whereevery deploy log.
• rollback
  Reverting a deploy to the previous version when something breaks.Whereincident response.
• hotfix
  An emergency fix shipped outside the normal release cycle.Where"we hotfixed it Friday night."
• feature flag
  A switch to turn a feature on/off in production without redeploying. Ship code dark, flip it on later.Where"we have it behind a flag."

Release Stages

• alpha
  Earliest pre-release. Expect bugs. Insider-only.Where"Claude Code is in alpha."
• beta
  Pre-release that's mostly working. "Private beta" or "public beta."Wherewaitlist signup pages.
• GAGeneral Availability
  Officially released to everyone. The "we're live" moment.Where"the feature is now GA."
• deprecated
  Old, still works, but will be removed eventually. A "switch to the new way" warning.WhereAPI doc warnings.

AI & Claude Code

• LLMLarge Language Model
  The kind of AI that Claude, ChatGPT, and Gemini are.Whereevery AI blog post since 2023.
• model
  Generic word for any trained AI. Claude Opus 4.7 is a model.Where"what model are you using?"
• prompt
  The text you send to an LLM. The "system prompt" is the hidden instructions that shape its behavior across a session.Where"tweak the prompt."
• context window
  How much text an LLM can hold in its working memory at once.Where"Claude has 1M context."
• token
  The unit LLMs see, roughly 0.75 words. Pricing is per-token.Where"you burned 200k tokens."
• agent
  An LLM that can use tools and take multi-step actions on its own. Claude Code is an agent.Where"build an agent for X."
• MCPModel Context Protocol
  Anthropic's open standard for connecting LLMs to tools and data. The plug between Claude and everything else.WhereClaude Code config.
• RAGRetrieval-Augmented Generation
  Giving an LLM access to your documents at query time so it can answer based on them.Whereevery AI startup pitch since 2024.
• hallucination
  When an LLM confidently makes up facts.Whereevery AI critique post.
• hook
  In Claude Code: code that runs at a specific moment (before a tool call, after, on stop). Guard rules are hooks.WhereClaude Code config.
• subagent
  A Claude instance spawned by Claude to handle a focused subtask.WhereClaude Code's context-guard skill.

Tools You Touch

• CLICommand Line Interface
  A text-based tool you run in a terminal. The opposite of a clickable app.Whereevery Claude Code command.
• IDEIntegrated Development Environment
  A code editor with extra developer tools built in. VS Code and Cursor are IDEs.Where"open your IDE."
• SDKSoftware Development Kit
  A library that wraps an API in your programming language so you don't have to make raw HTTP calls.Where"Stripe SDK," "Anthropic SDK."
• API key
  A long secret string that authenticates you to a service.Whereevery integration setup.
• env varenvironment variable
  A config value passed in from outside your code, like API_KEY=sk_live_abc... Lives in the .env file.WhereVercel env settings, "leaked .env" horror stories.

Web & Internet Plumbing

• frontend
  The browser-side code. What users see and click.
• backend
  The server-side code. Databases, business logic, APIs.
• endpoint
  A specific URL your code can call to get data or trigger something.Whereevery API doc.
• webhook
  A URL where another service posts events to you. The inverse of an API call: they call you.WhereStripe webhooks, Zapier triggers.
• DNSDomain Name System
  The internet's phonebook. Maps domain names (yourdomain.com) to server IP addresses.Where"DNS hasn't propagated yet," domain setup.

Culture Slang You'll Hear

• ship it
  "Just release it; stop polishing." A cultural battle cry.Wheredev Twitter forever.
• dogfooding"eat your own dog food"
  Using your own product internally before shipping it to customers.Where"we dogfooded it for a month first."
• technical debt"tech debt"
  Shortcuts taken now that you'll pay for later. The "we'll clean it up someday" pile.Whereevery engineering retro.
• refactor
  Restructuring code without changing what it does. Cleaning up without adding features.Where"let me refactor this first."
• edge case
  A rare or unusual input that breaks your code. The empty list, the user with no name.Whereevery code review.
• yak shaving
  Doing pointless sub-tasks that pile up while trying to accomplish one real thing.Where"I went yak shaving on the build config for 3 hours."
• on-call
  The engineer responsible for handling production incidents during a given shift. Usually rotates weekly.Where"I'm on-call this week."
• postmortem
  A blameless write-up after an incident. What broke, why, what we're changing.WhereCloudflare blog, status pages.
• MVPMinimum Viable Product
  The smallest version of something that proves the idea works. The Tier 1 startup vocabulary word.Where"ship the MVP first."