SaaS architecture glossary, in plain English.
Sixteen terms founders and product teams hear in architecture reviews, explained without jargon.
Rajesh Ayyavu, TenlyrUpdated 2026-11-03The short answer
Sixteen terms founders and product teams hear in architecture reviews, explained without jargon. Search for a term, or scroll.
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Plain English
No jargon, no assumed background.
Built for founders
The terms you hear in architecture reviews.
Terms
Written for founders and product teams, not engineers.
16 terms
SaaS architecture review
A written health check of how a software product is built. It finds what could break as the product grows, ranks problems by urgency and says what to fix first.
Multi-tenancy
One software product serving many customers (tenants), with each customer's data kept separate from the others'.
Tenant
One customer organisation using a multi-tenant product, with its own users and data.
Data isolation
The rules and design that make sure one customer can never see or change another customer's data.
RBAC (role-based access control)
A way to control who can do what by giving users roles, such as admin or viewer, each with defined permissions.
API
A defined way for one piece of software to ask another to do something or return data.
N+1 query
A slow pattern where a page runs one extra database query for each item in a list instead of fetching them together.
Database index
A structure that lets the database find rows quickly, like an index in a book. The right indexes make queries fast; missing ones make them slow.
Technical debt
Shortcuts in the code or design that save time now but make every future change slower or riskier.
Background job
Work done outside the user's request, such as sending emails or processing exports, so the product stays fast.
Row-level security
A PostgreSQL feature that restricts which rows of a table each user or customer can see, enforced by the database itself.
Rate limiting
Capping how many requests a customer or user can make in a period, so one heavy user cannot slow the product for others.
Caching
Keeping a copy of a result so it can be reused instead of recalculated, making repeated requests faster and cheaper.
LLM (large language model)
The kind of AI model behind text features such as chat, summaries and drafting. Cost and speed depend on how much text is sent and received.
Hallucination
When an AI model produces an answer that sounds confident but is wrong or invented.
Product engineering
Building a software product with attention to what to build, how it will grow, and how it stays safe and healthy after launch, not just writing code.
Keep reading
Written by Rajesh Ayyavu, founder and software architect at Tenlyr. He reviews SaaS products and fixes backend, database and AI problems. Last updated 2026-11-03. LinkedIn
Common questions
What is multi-tenancy in SaaS?
Multi-tenancy means one software product serves many customers, with each customer's data kept separate from the others'.
What is an N+1 query?
It is a slow pattern where a page runs one extra database query for every item in a list instead of fetching all the items together.
What is technical debt?
Technical debt is shortcuts in code or design that save time now but make every later change slower or riskier.
Not sure which term applies to you?
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