Free Tools for Key-Value Stores
Free tools for the jobs that come with running a key-value store: working out cluster slots, looking inside a snapshot, reading a server’s traffic, converting DynamoDB JSON, bulk-loading data, making sense of a keyspace and planning how keys spread over servers. Each one runs in your browser. There’s no sign-up and nothing to install.
Nothing you paste leaves your browser. The tools don’t send anything anywhere, and each tool page’s security policy stops it from fetching or loading anything from another site. Your keys, data and cluster layout stay on your machine.
Hash Slot Calculator
Find which of a cluster’s 16,384 slots a key lands in, and which primary holds it. Paste a multi-key command to see whether a cluster would run it or answer CROSSSLOT, or paste a whole key list to see how it spreads across the primaries. Works with Redis Cluster and Valkey Cluster.
Typed JSON Converter
Turn DynamoDB’s typed JSON, where every value is wrapped in its type, into plain JSON, and plain JSON back into typed JSON you can send to DynamoDB. It reads Scan and Query output, exports to S3 and stream records, and keeps every digit of every number.
Mass Insert Builder
Turn CSV, JSON or plain commands into a file in the Redis protocol, ready for redis-cli --pipe or valkey-cli --pipe, the fast way to load a lot of data. It also turns captured protocol bytes back into readable commands and replies.
Keyspace Map
Paste the output of --scan and see what a keyspace holds: the prefixes as a tree with counts, the naming patterns behind the keys with IDs folded together, and naming slips such as usr: next to user:.
Consistent Hashing Playground
Spread keys over a few servers with modulo hashing, a hash ring, rendezvous hashing and jump hash, then add or remove a server and count what moves. It shows why modulo hashing reshuffles almost everything and the others don’t.
Open the Consistent Hashing Playground
Snapshot Viewer
Open a Redis or Valkey dump.rdb and see what’s in it: keys by type and database, the biggest keys, the prefixes that take the most space, expiries, and any key’s value. It reads every format from Redis 2.6 to 8.10 and Valkey 7.2 to 9.1, and the payloads of the DUMP command, without putting any load on the server.
Traffic Analyzer
Load what MONITOR printed and see what a Redis or Valkey server is busy with: commands per second, the command mix, the busiest keys, key patterns and clients, how the keys would spread over a cluster, and commands worth a second look, such as KEYS or reads of whole collections. Its cache curve shows how many keys a cache needs for a given hit rate, and it matched a real Valkey server to within a third of a point.
How the Tools Are Built
- One library file each, no dependencies. Each tool’s logic is one JavaScript file, and the web page, a command line in Node.js and the tests all load it.
- Checked against the real thing. Each tool was checked against real Valkey 9.1.2 and Redis 8.10.2 servers, the AWS SDK or reference code. The recorded answers and results are published with the code, and the tests replay them.
- Open source. Everything is on GitHub under the Apache License 2.0. Each tool’s folder has a README that is its full manual.
More tools are on the way. If there’s one you’d like to see, the contact page is the place to say so.