Reference
381 pages. Every fenced example is compiled through the real compiler in CI, so a page cannot describe a language this release does not have.
An `agent` is a declaration — instructions, tools, model — and calling it is calling a name. The first-day mistake is treating…
`app.Apis` publishes your app to a third party over HTTP. You never write a controller or an endpoint handler — you EXPOSE what…
A class is an in-memory shape — data plus the behaviour that belongs to it — and it never touches the database. That is the whole…
The cross-cutting settings an app declares in one place — the app config object. Two kinds live here: the external providers and…
The PLATFORM assigns this number at create and you never set it — invoice codes, ticket numbers. NOT a manual order a person…
What your app says while it runs, and what the compiler says about it. The first-day mistake is reaching for a print statement —…
An entity is a table — and the rules that are true about it. Not just its columns: what must hold for a row to exist, and who may…
A fixed set of named values, used as a member type. By default an enum stores as a compact number; add [Type(string)] to store…
A function is where your app's logic lives — a top-level unit of work, written like a C# method, that runs on the server. It is…
Two ways to make an outbound HTTP call. A `client` block is a typed wrapper around a known API — name the base URL once, declare…
Turn a value into a JSON string and a JSON string into a typed object — the C#-faithful System.Text.Json spelling…
The local develop-and-debug loop for an Osy# app — for the person in the editor and the coding agent at the CLI alike. Run your…
How you make text findable in Osy#. You never touch a vector, an index, or an embedder — you mark a text field [Searchable] and…
A workflow run can outlive the deploy that started it. Deploying with --new-version freezes the code and data shape the running…
How you read data in Osy#. You write C# LINQ; it becomes one SQL statement. The rules that follow from that are the whole model:…
Realtime in Osy# is one construct: a topic. A topic is a declared, addressable destination — publishing to one delivers the value…
A schedule produces work on a cadence. Each occurrence creates a row of the entity its Template names — carrying whatever context…
How authorization works in Osy#, end to end. Everything is denied until you grant it; a grant is compiled into every query rather…
The pure standard library, and the one fact about it that changes how your app feels: 126 of its 155 methods run in the BROWSER…
Replacing a stored file's content while keeping what it said before. The FILE is the identity — a record pointing at it never…
A `[Test]` reaches the network for real — `Http.*` and a typed `client { }` operation both run inside a test, against the live…
The complete vocabulary of built-in types — the scalars you can store, the collections, the two callable spellings (`Action` and…
Two controls over a stored PDF: a reader with fit, zoom and a real text layer, and a thumbnail that draws one page as a picture…
Any call that leaves the platform — an outbound client call, an external service — is made a durable step by the compiler. In a…