Key-Value Store

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What is the Key-Value Store?

The RelayX Key-Value Store stores and retrieves small pieces of shared state with low latency.

Key properties:

• Values are stored under a string key
• Any client can read or write a value
• Writes overwrite previous values (last-write-wins)
• Scoped to your RelayX account
• Values persist until explicitly deleted

Not Available for iOS

The Key-Value Store is not currently available in the Swift SDK.

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Initializing the Store

Before any KV operations, initialize the store from a connected client:

const kvStore = await client.initKVStore();

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Writing a Value

Use put() to create or update a key:

// Store different value types
await kvStore.put("config.maxRetries", 5);
await kvStore.put("featureFlags.newUI", true);
await kvStore.put("service.metadata", { region: "ap-south-1" });
await kvStore.put("service.name", "my-service");

Key Rules

• Must be a non-empty string
• Allowed characters: a-z, A-Z, 0-9, _, -, ., =, /

Supported Value Types

Type	Example
String	"hello"
Number	42, 3.14
Boolean	true, false
Object/Dict	{ "key": "value" }
Array/List	[1, 2, 3]
Null	null

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Reading a Value

Use get() to retrieve a value by key:

const retries = await kvStore.get("config.maxRetries");
console.log(retries); // 5

const missing = await kvStore.get("nonexistent.key");
console.log(missing); // undefined or null

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Deleting a Key

Use delete() to permanently remove a key:

await kvStore.delete("featureFlags.newUI");

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Listing All Keys

Use keys() to get all stored keys:

const allKeys = await kvStore.keys();
console.log(allKeys); // ["config.maxRetries", "service.metadata", ...]

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Good Use Cases

The Key-Value Store works best for:

• Configuration values — app settings, thresholds
• Feature flags — toggle features on/off
• Shared state — small pieces of data multiple clients need
• User preferences — per-user settings

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What This Is Not

The Key-Value Store is not:

• A database (no queries, joins, or transactions)
• A coordination service (no locking)
• A history tracker (no versioning)

It stores the latest value only. Newer writes replace older ones.

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Guarantees

Guarantee	Description
Single value per key	Each key holds exactly one value
Persistence	Values persist until explicitly deleted
Last-write-wins	Most recent successful write determines the value
Read consistency	Reads return the latest stored value

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Common Mistakes

Mistake	Why It's a Problem
Using it as a database	No queries, no transactions, no joins
Assuming coordinated writes	Concurrent writers are not synchronized
Storing critical state	No strict consistency guarantees
Large payloads	Designed for small values only

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Limitations

• No atomic operations
• No partial updates
• No conditional writes
• No history or versioning

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