Engineering Glossary · 17 Core Concepts
Software Lifecycle Cloud & AI Engineering Glossary.
Clear, hype-free technical definitions for modern cloud architecture, AI agent sandboxes, serverless data primitives, and declarative infrastructure.
Agents Agent sandbox An agent sandbox is where a coding agent’s work lives on KERNSTACK: a dedicated agent/<id> branch in hosted git, deployed to its own agent-<id> environment. Your main branch is never touched, and nothing leaves the sandbox without a reviewed plan. Delivery Blueprint A blueprint is a starter scaffold for a KERNSTACK workload — for example func-go-minimal for a Go function or work-nodejs-minimal for a Node.js worker — copied into the project by kernstack add and published in the template gallery. Edge Canonical redirect A canonical redirect is the gateway behaviour (canonical_redirects on a bucket prefix route, on by default) that 301-redirects alternate page URLs — trailing-slash and legacy .html forms — onto the single canonical URL the route publishes. Data Change stream A change stream is a table declaration — change_stream: { function } — that invokes a named function with batched changes to that table’s items. It is how a KERNSTACK table announces writes without a separate queue or streaming product. Pricing Credit A credit is KERNSTACK’s single unit of metering: compute costs 0.01 credits per GiB-second, storage 0.04 credits per GB-hour, egress 9.00 credits per GiB, and catalogue inference is priced per token or image in credits. One balance pays for everything a project does. Sovereignty Data residency Data residency on KERNSTACK means a project runs in one declared European zone on bare-metal infrastructure KERNSTACK operates itself — not in a hyperscaler region rented underneath — and every environment of the project answers the residency question the same way. Access Environment isolation Environment isolation is the separation between a project’s targets — default (production), preview targets, and agent-<id> environments — each instantiating the same stack.json with its own data, routes, and keys, so work in one cannot touch another. Workflow Human approval Human approval is a workflow step — { "human": { "title": "..." } } — that pauses a run until a named person decides. The decision, the decider, and the record as shown are stored in the run, and the workflow resumes with the outcome as data. Delivery OpenSpec plan An OpenSpec plan is the change a KERNSTACK topic asks @agent to write in Plan mode: a proposal, requirements with scenarios, and a task list, shown as a card in the thread. Product files and deploys stay closed until someone on the topic approves that card. Delivery Plan diff A plan diff is the preview kernstack plan produces before any deploy: the creates, updates, and deletes the new stack.json would cause — with deletes listed under “Will delete” and refused until a person passes --confirm-destructive. It is also available as kernstack plan --json. Edge Prefix route A prefix route is a gateway route of type "prefix" that serves a bucket — usually a built frontend or published content — under a path, with default_key for the index document, optional prefix restriction, CDN delivery, canonical redirects, and a declared fallback for unknown paths. Architecture Project graph The project graph is the whole system a KERNSTACK project declares in stack.json — gateway routes, functions, workers, tables, buckets, search indexes, workflows, and secrets — instantiated per environment target and changed only through reviewed plans. Pricing Scale to zero Scale to zero means idle compute stops billing: functions charge 0.01 credits per GiB-second only while executing, and workers with min_instances: 0 stop after their idle_timeout_ms. An idle project spends on storage (0.04 credits per GB-hour), not on standing replicas. Manifest stack.json stack.json is the manifest file that declares a KERNSTACK project: the stack target, gateway routes, and every resource — functions, workers, tables, buckets, search indexes, inference endpoints, secrets, alert rules, and workflows. It lives in git and is applied with kernstack deploy. Search Vector index A vector index is a KERNSTACK search index with index_type "vector", declared over the tables and buckets that hold the source records. Retrieval runs inside the project, fed by embeddings from catalogue models such as text-embed-v1 (3 credits per 1,000 tokens) or a custom inference endpoint. Runtime WASM function A WASM function is a KERNSTACK function: a Go handler compiled to WebAssembly, declared under resources.functions, and invoked through a gateway route, a schedule, a table change stream, or a workflow step. Websocket routes must target functions. Runtime Worker A worker is a KERNSTACK container process for work that outlives a single request — a Go binary or a Node.js, Python, or PHP runtime — declared under resources.workers with its own HTTP port, memory and CPU sizing, idle timeout, and instance limits.
FAQ
Frequently asked questions
It provides clear, implementation-grounded definitions of core concepts across the Software Lifecycle Cloud — from WebAssembly sandboxes and HNSW vector indexing to agent harnesses and declarative stack.json infrastructure.
Yes. Each glossary term links directly to the corresponding KERNSTACK platform capability and includes a concrete stack.json or SDK snippet.
Start with the Software Lifecycle Cloud pillar page and the Project Graph glossary entry to see how infrastructure, code, intelligence, and collaboration connect.
Connected in the Project Graph
Related capabilities, architectures, and comparisons
Platform · AgentsAgent sandboxesIsolated sandboxes for coding agentsPlatform · InsightAnalyticsProduct analytics on the same fabricPlatform · DataBucketsObject storage with presigned uploadPlatform · EdgeCDNCached delivery for apps and assetsPlatform · PeopleCollaborationBoards and conversations on the projectPlatform · ComputeFunctionsGo WebAssembly HTTP handlers
Ship your stack on the Software Lifecycle Cloud.
Closed preview on dedicated European infrastructure. Bring a repository or start from a blueprint.