What is Tether?

Tether turns ordinary Go functions into a live backend. A query reads data, and Tether remembers which rows and collections it read. A mutation writes data. When a mutation's writes commit, Tether re-runs the queries that depend on the changed data and pushes the new results to connected clients.

You own the Go application and the database. Tether handles subscriptions, dependency tracking, and WebSocket delivery.

Reactive by defaultCopy Anchor Link

A query is a live computation, not an endpoint clients poll. Rows a query loads are tracked automatically. When a result should also react to new rows, such as an empty list or a count, you declare a collection or table dependency.

When several clients subscribe to the same query with the same parameters, Tether runs it once and sends everyone the result. Guards keep this sharing working with permissions: each user's access is checked separately, and users with the same access share the query.

Read Reactivity before you write more complex queries. Tether tracks writes made through its database handle, not arbitrary changes elsewhere in your system.

Secure defaults, your rulesCopy Anchor Link

Queries and guards get read-only database handles. Internal functions are hidden from clients. Tether also checks WebSocket origins, limits message sizes, and applies safeguards to file storage by default.

Your application still decides who can read or write each resource, validates parameters, and chooses what data to return. Authentication tells you who the caller is; guards and mutation checks decide what they're allowed to do.

Infrastructure that grows with your appCopy Anchor Link

Start with SQLite in a single Go process. Move to PostgreSQL when you need multiple instances. Engines that share a PostgreSQL database coordinate updates and scheduled tasks through it, so you don't need Redis or a message broker.

File storage works the same way: start with local disk, then switch to an S3-compatible adapter. Switching adapters doesn't migrate existing files or data for you.

PhilosophyCopy Anchor Link

Tether follows four main principles:

• Radical simplicity. Keep the public API small and obvious.
• Effortless infrastructure changes. Make backend swaps straightforward.
• No vendor lock-in. Run a self-contained Go binary on infrastructure you control.
• Pluggable, not hard-coded. Put external infrastructure behind adapters.

Tether fits apps whose screens should reflect database changes as they happen, such as collaborative tools, dashboards, chat, and operational interfaces. It doesn't provide a login service, a UI framework, or a managed database. You bring your identity provider, models, and application rules.

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