48 terms
Glossary
The words on pricing pages, explained for someone setting these services up for the first time, and what each one means for what you pay.
- APM and tracing Also called: observability
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Tools that measure where time goes inside your app, request by request, across services. Useful once something is slow and you cannot tell why.
For your bill: Usually priced per GB or per event ingested. Most small projects do not need it.
- Background job and queue Also called: worker, task queue, cron, durable workflow
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A job is work your app hands off to run outside a web request; a queue holds jobs until a worker runs them, retrying the ones that fail. A durable workflow remembers which steps finished, so a long process survives crashes and restarts.
For your bill: Hosted services usually bill per run or per step. One job that fans out into many steps can use a free allowance faster than expected.
- Backups and point-in-time recovery Also called: PITR
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Daily backups let you restore yesterday’s database. Point-in-time recovery lets you restore to any minute within a window, such as just before a bad migration.
For your bill: Many free tiers have no backups at all. Check this before you store anything you cannot recreate.
- Card required
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Whether you must enter a payment card to sign up for a free tier. Providers ask for one to stop abuse, and some charge it automatically once you pass a limit.
For your bill: With no card on file, the worst case is your project stopping, not a bill.
- CDN (content delivery network)
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Servers around the world that keep copies of your images, scripts and pages close to visitors, so they load faster. Most app hosts include one.
For your bill: Priced per GB delivered, sometimes more for Asia, South America and Africa. Free plans cover most small sites.
- Cold start
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The delay when a stopped app or function has to start up before it can answer. Serverless functions take milliseconds to a second; a sleeping container can take up to a minute.
For your bill: The first visitor after a quiet spell waits. Paid plans usually keep at least one copy running to avoid it.
- Connection pooling Also called: pooler, PgBouncer
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A layer that lets many short-lived app processes share a small number of database connections. Serverless functions open a new connection on almost every request, which can exhaust a small database without one.
For your bill: Small database plans cap connections. "Too many connections" errors on a quiet site usually mean you need the pooled connection string.
- Container (Docker)
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A package of your app plus everything it needs to run, described in a Dockerfile. Any host that runs containers can run it the same way, which makes moving between hosts easier.
- Cron job and heartbeat check
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A cron job is a script that runs on a schedule. A heartbeat check expects the script to ping it each time it runs and alerts you when a ping does not arrive.
- Database branching
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A quick copy of your database, like a Git branch, so you can test a change against real data without touching production.
For your bill: Useful when each pull request gets its own preview deployment. Not needed for a first project.
- Dedicated IP
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An email sending address used only by you, instead of a pool shared with other customers.
For your bill: Only helps if you send tens of thousands of emails steadily. Below that, a good shared pool delivers better, so do not pay extra for one early.
- Deliverability
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Whether your email reaches the inbox rather than spam. It depends on your domain’s reputation, the sending service’s reputation and the DNS records above.
- DNS
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The internet’s address book: records that point your domain name at your host, your email provider and so on. Your registrar gives you DNS for free; you only change it when a host tells you to.
- Egress Also called: bandwidth, data transfer, outbound traffic
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Data leaving the provider’s network: pages, images and downloads sent to your visitors. Data coming in (ingress) is almost always free.
For your bill: The most common surprise on a cloud bill. AWS, Google Cloud and Azure charge per GB after a small allowance; many smaller hosts include terabytes in the price.
- Error tracking
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A small library in your app that reports crashes with the stack trace, the browser and what the user did, grouped so you see each bug once.
- Free tier, trial and credits
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A free tier lasts as long as you stay under its limits. A trial ends after a set time. Credits are a sum of money you use up. This site counts only the first as free.
For your bill: A trial or credit that runs out turns into a bill, often without much warning.
- Headless (unstyled) components Also called: unstyled components, primitives
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Components that handle behaviour and accessibility (keyboard use, focus, screen readers) but come with no visual style, so you style them yourself.
For your bill: Free, and more work up front than a styled library, but you never fight someone else’s design.
- Lock-in
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How hard it is to leave a service. Standard things (Postgres, Docker, SMTP) move easily; proprietary databases, auth user stores and platform-specific functions take work to move.
For your bill: Not a reason to avoid a good free tier, but worth knowing which parts you would have to rewrite.
- Managed database
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A database the provider runs for you: they install it, apply updates, take backups and replace failed hardware. You connect to it with a connection string.
For your bill: Costs more than installing Postgres on your own VPS, and removes the job most people do badly: backups.
- MAU (monthly active users) Also called: monthly retained users
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The number of different users who sign in at least once in a month. Auth services price by it, and each defines "active" slightly differently.
For your bill: Free tiers range from a few thousand to over a million MAU, so the same app can be free on one provider and paid on another.
- Merchant of record Also called: MoR, reseller
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The business legally selling to your customer. A merchant-of-record provider buys from you and resells to the customer, so it collects and pays sales tax and VAT in every country.
For your bill: Fees are higher (often around 5% plus a fixed amount) than a plain processor, but you avoid registering for tax in the places your customers live.
- MFA (multi-factor authentication) Also called: 2FA, passkeys
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A second proof of identity at sign-in, such as a code from an app or a passkey. Some auth providers only include it on paid plans.
- OAuth and social login
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The standard behind "Sign in with Google" or "with GitHub". Your app never sees the user’s password; the other service vouches for them.
- ORM (object-relational mapper) Also called: query builder, database client
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A library that lets your code read and write a SQL database with the language’s own objects and functions instead of SQL strings, and usually manages migrations too.
For your bill: Free in almost every case. What it costs is lock-in to its schema format and, on some serverless hosts, a driver or proxy it needs.
- PaaS (platform as a service) Also called: app host, app platform
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A service that takes your code, usually straight from a GitHub repository, builds it and runs it. It handles servers, HTTPS certificates and restarts, so you never log in to a machine.
For your bill: Costs more per unit of CPU and memory than a VPS, and saves you the time of running one.
- Postgres (PostgreSQL)
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The most widely used open-source relational database. Most frameworks, tutorials and AI app builders support it, which makes it the safe default if you are unsure.
- Region
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The data centre location where your server or database runs, such as Frankfurt or Virginia. Put your app and its database in the same region, near most of your users.
For your bill: Cheap plans are often only sold in a few regions, and some services cannot move a project to another region later.
- Renewal price
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What a domain costs every year after the first. Registrars often discount the first year heavily and make it back at renewal.
For your bill: Compare renewal prices, not the first-year offer; you pay the renewal for as long as you keep the domain.
- S3 API (S3-compatible storage) Also called: S3-compatible, object storage, bucket
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The way Amazon S3 lets programs store and fetch files in buckets. Most storage providers copy it, so the same code and tools work with any of them.
For your bill: Being S3-compatible makes it cheap to move providers later: change the endpoint and keys, not your code.
- Scale to zero
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The service shuts down completely when nobody uses it and starts again on demand. It is the same idea as sleeping, described as a feature.
For your bill: You pay nothing while idle, in exchange for a cold start on the next request.
- Self-hosting and open source
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Open-source software publishes its code; self-hostable means you can run it on your own server instead of paying the vendor’s hosted version.
For your bill: No per-user fees, but you pay for the server and spend your own time on updates, backups and security.
- Server rendering, static generation and SPAs Also called: SSR, SSG, SPA, islands
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Server rendering (SSR) builds each page on the server when it is requested; static generation (SSG) builds pages once, ahead of time; a single-page app (SPA) builds them in the browser with JavaScript. Islands send HTML and add JavaScript only to the parts that need it.
For your bill: Static pages can be hosted free almost anywhere. Server rendering needs a server or serverless functions, which is where hosting costs start.
- Serverless Also called: functions, edge functions, lambdas
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Your code runs only when a request arrives, then stops. You do not choose a server size; the platform starts copies as traffic needs them.
For your bill: Billed per request and per unit of compute time, so a quiet project costs close to nothing and a busy one can cost more than a fixed server.
- SLA (service level agreement)
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A written promise of uptime, such as 99.9%, with a refund of part of your bill if the provider misses it. It does not make outages less likely.
For your bill: Usually only on paid or business plans. A side project does not need one.
- Sleeping (spin down) Also called: idle timeout, paused project
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Many free tiers stop your app or database after a period with no traffic, from 15 minutes to a week. The next request wakes it, slowly, and some services delete projects that stay asleep too long.
For your bill: Fine for a demo; a problem for a bot, a webhook receiver or anything a customer relies on.
- SMTP
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The standard protocol for sending email. Almost every email service gives you an SMTP server address and password, which works with any framework even if it has no SDK for that service.
- Spend cap Also called: hard limit, budget alert
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A setting that stops a service, or warns you, when a bill reaches an amount you choose. A cap stops spending; an alert only emails you.
For your bill: AWS, Google Cloud and Azure offer alerts but no hard cap on most services. Check what happens at the limit before relying on it.
- SPF, DKIM and DMARC
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Three DNS records that prove an email came from your domain. Your email provider tells you what to add; it takes about ten minutes.
For your bill: Gmail and Yahoo now reject or spam-folder bulk mail without them, so set them up before your first send.
- SSO and SAML Also called: enterprise SSO, SCIM
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Lets a company’s employees sign in to your app with their work account (Okta, Microsoft, Google Workspace). SAML is the protocol; SCIM adds and removes users automatically.
For your bill: Often the most expensive line on an auth bill, charged per company connection. You need it only when business customers ask.
- TLS/SSL certificate Also called: HTTPS
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What makes the padlock appear and encrypts traffic to your site. Every host on this site issues one free and renews it automatically.
For your bill: Never pay for a basic certificate.
- Tokens (AI pricing) Also called: input tokens, output tokens, context window
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The pieces of text an AI model reads and writes; a token is roughly three quarters of an English word. APIs charge per million tokens, with separate prices for input (your prompt) and output (the reply).
For your bill: Output usually costs several times more than input, and long conversations resend the whole history each time. Prompt caching and batch discounts can cut the bill a lot.
- Transactional email
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Email your app sends to one person because of something they did: a sign-up confirmation, a password reset, a receipt. It is sent through an API or SMTP.
For your bill: Priced per email. Different from newsletters, which are priced per subscriber.
- Uptime monitoring
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A service that loads your site every few minutes from outside and alerts you when it stops answering, so you hear about an outage before your users tell you.
- Usage-based pricing and overage Also called: pay as you go, metered
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You pay for what you use (requests, GB, compute hours) rather than a flat fee. Overage is the price for going past what a plan includes.
For your bill: Cheap while small, harder to predict. Look for a spending limit or alerts before you launch anything that could get a traffic spike.
- vCPU
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One virtual processor core. "Shared" vCPUs are shared with other customers and can slow down when neighbours are busy; "dedicated" ones are yours alone and cost more.
For your bill: Compare plans on vCPU, RAM and disk together: an entry price often hides a much smaller machine.
- VPS (virtual private server) Also called: cloud server, droplet, instance
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A slice of a physical server that behaves like your own Linux machine: you get root access and install whatever you like. You also keep it updated and secure yourself.
For your bill: A flat monthly price, usually with a bundle of traffic included. The cheapest way to run something that has to stay on all the time.
- WAF and DDoS protection
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A web application firewall blocks malicious requests before they reach your app. DDoS protection absorbs floods of junk traffic meant to knock a site offline.
For your bill: Basic DDoS protection comes free with most CDNs. Custom WAF rules are usually a paid add-on.
- WHOIS privacy
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Hides your name, address and email from the public domain registration record. Most good registrars include it free.