Low-Level KV Storage

Use the built-in key-value store on ActorContext for durable string and binary data alongside actor state.

Every Rivet Actor includes a lightweight key-value store on c.kv. It is useful for dynamic keys, blobs, or data that does not fit well in structured state.

If your data has a known schema, prefer state. KV is best for flexible or user-defined keys.

Basic Usage

Keys and values default to text, so you can use strings without extra options.

import { actor } from "rivetkit";

const greetings = actor({
	state: {},
	actions: {
		setGreeting: async (c, userId: string, message: string) => {
			await c.kv.put(`greeting:${userId}`, message);
		},
		getGreeting: async (c, userId: string) => {
			return await c.kv.get(`greeting:${userId}`);
		},
	},
});

Value Types

You can store binary values by passing Uint8Array or ArrayBuffer directly. Use type when reading to get the right return type.

import { actor } from "rivetkit";

const assets = actor({
	state: {},
	actions: {
		putAvatar: async (c, bytes: Uint8Array) => {
			await c.kv.put("avatar", bytes);
		},
		getAvatar: async (c) => {
			return await c.kv.get("avatar", { type: "binary" });
		},
		putSnapshot: async (c, data: ArrayBuffer) => {
			await c.kv.put("snapshot", data);
		},
	},
});

TypeScript returns a concrete type based on the option you pass in:

import { actor } from "rivetkit";

const example = actor({
	state: {},
	actions: {
		demo: async (c) => {
			const textValue = await c.kv.get("greeting");
			//    ^? string | null

			const bytes = await c.kv.get("avatar", { type: "binary" });
			//    ^? Uint8Array | null
		},
	},
});

Key Types

Keys accept either string or Uint8Array. String keys are encoded as UTF-8 by default.

When listing by prefix, you can control how keys are decoded with keyType. Returned keys have the prefix removed.

import { actor } from "rivetkit";

const example = actor({
	state: {},
	actions: {
		listGreetings: async (c) => {
			const results = await c.kv.list("greeting:", { keyType: "text" });

			for (const [key, value] of results) {
				console.log(key, value);
			}
		},
	},
});

If you use binary keys, set keyType: "binary" so the returned keys stay as Uint8Array.

Range Operations

Use listRange(start, end) to read an arbitrary half-open range [start, end). Use deleteRange(start, end) to clear that same range efficiently.

import { actor } from "rivetkit";

const example = actor({
	state: {},
	actions: {
		pruneAndScan: async (c) => {
			const encoder = new TextEncoder();
			const active = await c.kv.listRange(
				encoder.encode("job:"),
				encoder.encode("joc:"),
				{
					keyType: "text",
				},
			);

			await c.kv.deleteRange(
				encoder.encode("job:old:"),
				encoder.encode("job:old;"),
			);

			return active.map(([key, value]) => ({ key, value }));
		},
	},
});

Batch Operations

KV supports batch operations for efficiency. Defaults are still text for both keys and values.

import { actor } from "rivetkit";

const example = actor({
	state: {},
	actions: {
		batchOps: async (c) => {
			await c.kv.putBatch([
				["alpha", "1"],
				["beta", "2"],
			]);

			const values = await c.kv.getBatch(["alpha", "beta"]);
		},
	},
});

API Reference

ActorContext - c.kv is available on the context