Your API starts with a great spec.
ARCitect is an AI-native OpenAPI editor that helps you design, validate, and refine your API contract — before a single line of code is written.
Agentic, not autocomplete
ARCitect understands your intent across the full spec — not just the line you're on. It reasons about consistency, naming, and structure holistically.
One prompt. Every change it implies.
Describe what you want to change. ARCitect figures out everything that needs to move — across schemas, parameters, responses, and references — and surfaces it as a single reviewable set. You see the full picture before anything is committed.
Your spec, your contract
ARCitect produces a clean, portable OpenAPI 3.0 document. No lock-in, no proprietary format. It works anywhere specs work.
The loop that builds your spec
Provide as much or as little context as you’d like. ARCitect is highly proficient at this process and will fill in what’s missing — but it welcomes collaboration. The more you bring, the more precisely the output reflects your intent.
The refinement loop
Repeats across all four steps until your spec is complete. At every stage, nothing advances without your sign-off.
The four steps
Vision
PRDThe north star. What problem does this API solve, and for whom?
Vision is the highest-leverage document in the process — and the most forgiving place to make big decisions. A single sentence here can reshape everything downstream: entire feature families, data models, and API surfaces are added, removed, or reoriented based on what this document establishes. For leadership, it's a forcing function for alignment on scope and purpose before any technical investment is made. For product, it's the constraint that keeps the spec honest. For engineers, it's the "why" that makes every subsequent decision legible.
Get Vision right and the rest of the spec has direction. Skip it and you're building on assumption.
Features
PRDThe capabilities. What can users do with this product?
Features translates vision into product surface. Where Vision answers what this is for, Features answers what it does — the discrete capabilities a user or system can invoke. This is where product thinking matures into something buildable: use cases become concrete, scope boundaries become visible, and the shape of the API starts to emerge. For product, it's the clearest expression of user value. For engineering, it's the first signal of complexity — which features are straightforward, which require careful data modeling, which may need revisiting before the spec goes any further.
Features still operates at the level of intent, not implementation. That precision comes next.
Resources
SPECThe data models. What entities does the API own and persist?
Resources is where the spec becomes structural. Every entity the API owns — users, orders, sessions, documents — is defined here along with its fields, types, and relationships. This is the domain model that operations will be built on top of, and getting it right matters: a poorly modeled resource creates ripple effects across every endpoint that touches it. For engineering and data, this is the most important document in the process — the place where naming conventions, cardinality, and ownership boundaries get established before they become load-bearing. For product, it's a useful reality check on whether features are achievable with the data model being proposed.
A well-defined resource layer makes Operations nearly write itself.
Operations
SPECThe endpoints. How does the outside world interact with your data?
Operations is the most granular document in the process — and the most consequential. Every endpoint, method, parameter, request body, response schema, and status code is defined here in full. This is the contract: what consumers depend on, what Code Reactor generates from, what tests will validate. By the time ARCitect reaches this step, Vision has set the direction, Features has defined the surface, and Resources has established the data model — so Operations isn't guesswork. It's the precise, grounded expression of everything that came before it.
This document is the deliverable. Everything upstream exists to make it correct.
A document describes what you hope to build. A spec is what ships.
A production-grade OpenAPI spec does something no PRD or README can: it gives every part of your organization the same source of truth at the same time. Frontend and backend teams can build in parallel — not sequentially — because the contract between them is explicit, validated, and agreed upon before either side writes a line of code. Coding agents can generate implementations directly from it. Mock servers can simulate it. Tests can validate against it. The spec is the coordination layer.
And when things change — because they always do — ARCitect works with you to carry the change through. Not just the endpoint you touched, but everything the change implies: the schemas that reference it, the parameters that depend on it, the responses that need updating. The next version of your API arrives with the same consistency and quality as the first.
Build against the contract before the backend exists. No blocking, no assumptions, no rework.
Implement to a spec that's already been reviewed and agreed. Scope is clear before a function is written.
Coding agents generate implementations, tests, and clients directly from the spec. No interpretation required.
When the API evolves, ARCitect ensures every implication is surfaced and resolved. Consistency carries forward.
Start writing specs
that ship systems.
ARCitect is open to a limited beta cohort. We're prioritizing teams that own real APIs on AWS and founders building production-grade prototypes.
What you get- Early access to ARCitect and the full spec-as-source pipeline
- First access to Code Reactor self-serve when it opens
- Discounted GA pricing locked in at beta rates