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Show HN: KiviDB, a faster Redis-compatible memory database and vector cache

Show HN: KiviDB, a faster Redis-compatible memory database and vector cache

8 hours ago

KiviDB

KiviDB

KiviDB is a fast, multi-threaded alternative to Redis® and Valkey, written in Rust. It speaks the Redis protocol (RESP2 and RESP3), so existing Redis clients, redis-cli and libraries work unchanged, and it has full-text and vector search built in. It runs every core on a sharded in-memory key-value design, and persists to snapshots and an optional append-only file.

On the same 32 cores, KiviDB serves 21 million pipelined GETs per second: about 9× Redis 8 and 2.3× Dragonfly, with under half Dragonfly's p99 latency (benchmarks).

docker run -d -p 6380:6380 kividb/kividb
redis-cli -p 6380 PING        # PONG

KiviDB listens on 6380, not Redis's 6379, so the two can run side by side; point your client at that port, or pass --port 6379.

  • Protocol: Redis-compatible command surface (see COMMANDS.md for the supported commands)
  • Search and vectors: Redis Stack–style FT.* commands for full-text, tag, numeric and vector (FLAT / HNSW) search
  • Lua scripting: optional Cargo feature. EVAL, SCRIPT, FUNCTION, FCALL and related commands are available in builds with --features lua (see Scripting commands (Lua))
  • TLS: optional Cargo feature (--features tls)
  • Default listen address: 0.0.0.0:6380, with protected mode on
  • License: GNU Affero General Public License v3 (AGPL-3.0-only), open source; using KiviDB does not put your application under the AGPL; see License

Repository: github.com/kividbio/kividb · Website: kividb.io

How it compares

KiviDB Redis 8 Valkey 8 Dragonfly KeyDB
License AGPL-3.0 RSALv2, SSPLv1 or AGPL-3.0 BSD-3-Clause BSL 1.1 BSD-3-Clause
Language Rust C C C++ C++
Commands run on every core (sharded) one thread (I/O threads) one thread (I/O threads) every core (shared-nothing) several threads
Full-text and vector search (FT.*) built in built in (Query Engine) separate module built in no
Lua scripting lua build yes yes yes yes

As of October 2026. Something out of date or wrong? Please open an issue.

Performance

KiviDB benchmarks: throughput, latency, vector search and vector ingest

Throughput, latency, vector search and vector ingest. Click for the full-resolution video.

All figures below are from one session in October 2026 on AWS Graviton3 bare metal: the server on a c7gn.metal (64 vCPU), confined to 32 cores, and the load generator on a second c7gn.metal in the same placement group. Each engine ran alone on the server, one after another.

Key-value

memtier_benchmark through kivi-benchmark's run-matrix.sh: 10 million keys, 100-byte values, 30 s a scenario, mean of two rounds; 300 connections pipelined, 1,200 without pipelining.

Pipelined throughput: KiviDB, Dragonfly, Redis, Redis Cluster
ops/s KiviDB 1.1.0 Dragonfly 2.0.2 Redis 8.10 Redis Cluster (32 shards)
GET, pipeline 16 21.2M 9.1M 2.4M 4.7M
SET, pipeline 16 19.2M 8.5M 2.0M 4.7M
GET, no pipelining 3.07M 3.35M 1.32M 1.46M
SET, no pipelining 3.12M 3.38M 1.54M 1.46M
p99 latency, GET / SET, pipeline 16 0.36 / 0.42 ms 0.88 / 1.07 ms 2.2 / 2.7 ms
Memory per key 177 B 134 B 178 B 183 B
p99 latency, pipelined

Vector search

redis/vector-db-benchmark on glove-25-angular (1.18M vectors, 25 dimensions): HNSW with M=16 and EF_CONSTRUCTION=256, 100 clients uploading in batches of 64, then queries at ef 64, 128, 256 and 512.

Vector search: queries per second against recall
KiviDB 1.1.0 Dragonfly 2.0.2 Redis 8.10 (query engine)
Queries/s at ef 64 (recall@10) 59.3k (0.943) 41.3k (0.912) 31.8k (0.912)
Queries/s at ef 128 50.7k (0.961) 40.3k (0.937) 28.9k (0.937)
Queries/s at ef 256 31.5k (0.989) 36.2k (0.979) 21.1k (0.979)
Queries/s at ef 512 18.7k (0.998) 29.8k (0.995) 13.7k (0.995)
Ingest and index build 31 s 13 s 38 s
Memory after ingest 1.66 GB 1.13 GB 1.07 GB
Vector ingest time

Results depend on the environment. Treat published figures as one controlled capture, not a guarantee, and measure on your own hardware and workload.

Vector search (Redis Stack–style FT.*)

KiviDB implements Redis Stack–compatible search and vector commands, so existing clients and tutorials largely work unchanged. Use them for full-text (BM25), tags / numerics, and vector ANN (FLAT or HNSW) on hash fields.

Quick start

  1. Create an index on keys with a prefix, declaring at least one VECTOR field (HNSW or FLAT) and optional TEXT / TAG / NUMERIC fields:
redis-cli -p 6380 FT.CREATE idx ON HASH PREFIX 1 doc: SCHEMA \
  vec VECTOR HNSW 10 TYPE FLOAT32 DIM 128 DISTANCE_METRIC COSINE M 16 EF_CONSTRUCTION 128
  1. Store vectors as raw FLOAT32 little-endian bytes in a hash field (DIM × 4 bytes), the same convention as Redis Stack and redis-py / numpy blobs. Use your client's binary-safe HSET (the integration tests under tests/e2e/ have examples).

  2. Query with KNN (Dialect 2), passing the query vector as a named binary parameter:

redis-cli -p 6380 FT.SEARCH idx '*=>[KNN 10 @vec $q]' PARAMS 2 q <blob> DIALECT 2

The full command surface, filters, hybrid search and edge cases are in COMMANDS.md (search for FT.CREATE, FT.SEARCH, FT.HYBRID, and so on).

Persistence and restarts

  • Native snapshots (dump.kdb) store the keys, the index schemas, and, when you SAVE / BGSAVE with indexes populated, the HNSW graph of each vector field, so search quality after a restart matches the graph you had before shutdown.
  • While search indexes are being rebuilt at startup, most commands return LOADING until the rebuild finishes; PING, INFO and a few other commands still work.
  • After a large ingest, run SAVE (or schedule BGSAVE) so the next start reloads the graph from disk instead of rebuilding it from the hashes.

Builds

KiviDB comes in four variants, chosen by Cargo features at build time:

Variant Cargo features Adds
default none the core server, without Lua or TLS
lua lua Lua scripting (EVAL, EVALSHA, SCRIPT, FUNCTION, FCALL, …)
tls tls TLS listener, and TLS between cluster nodes and replicas
full lua,tls both

In a build without Lua, the scripting commands return an error. A build without TLS refuses to start if --tls-port is given, rather than serving plaintext.

Building from source

Requires a stable Rust toolchain (rust-toolchain.toml selects stable with rustfmt and clippy). The crate uses the 2024 edition; the oldest toolchain it is checked against is Rust 1.89, the version the Dockerfile builds with.

git clone https://github.com/kividbio/kividb.git
cd kividb

cargo build --release                      # default variant
cargo build --release --features lua       # with Lua scripting
cargo build --release --features tls       # with TLS
cargo build --release --features lua,tls   # full

./target/release/kividb

On Linux the server uses io_uring when the kernel allows it and falls back to Tokio otherwise (--io-model auto, the default).

To build the Docker image yourself, docker build -t kividb . builds the default variant; docker build --build-arg KIVIDB_FEATURES=lua,tls -t kividb:full . builds another one.

Running KiviDB

./target/release/kividb                    # listens on 0.0.0.0:6380
redis-cli -p 6380 PING

Any Redis client works; point it at port 6380.

Protected mode

Protected mode is on by default, as in Redis. While it is on, no bind address has been set (--bind or bind in the config file) and the default user has no password, only clients on the same machine (loopback) may connect. Any other client receives a -DENIED error that explains the options, and is disconnected.

To accept clients from other machines, do one of these:

  • set a password: --requirepass <password>, or ACL SETUSER default ><password>;
  • set a bind address: --bind <address>;
  • turn protected mode off: --protected-mode no, protected-mode no in the config file, or CONFIG SET protected-mode no from a local client.

If you turn it off or bind to a public address, make sure the server cannot be reached from the internet without a password.

Docker

Images are published to Docker Hub and the GitHub Container Registry, with the same tags in both:

docker pull kividb/kividb:latest
# or
docker pull ghcr.io/kividbio/kividb:latest

latest and version tags such as v1.1.0 are the default variant; v1.1.0-lua, v1.1.0-tls and v1.1.0-full are the others. Images are built for amd64 and arm64.

docker run -p 6380:6380 kividb/kividb

A container is reached through its network, never from loopback, so the image's default command is --protected-mode no. Arguments you pass replace that default, which turns protected mode back on. When you pass your own flags, set a password (recommended) or add --protected-mode no yourself:

docker run -p 6380:6380 ghcr.io/kividbio/kividb \
  --requirepass "change-me" \
  --databases 8 \
  --loglevel debug

With AOF persistence (mount a volume so data survives restarts; the server runs as user kividb in /home/kividb):

docker run -p 6380:6380 \
  -v $(pwd)/data:/home/kividb \
  ghcr.io/kividbio/kividb --aof --requirepass "change-me"

With --aof, every write is appended to appendonly.aof and the file is replayed on startup, so a crash loses at most about the last second of writes (the fsync interval) rather than everything since the last snapshot. When an AOF is present it is the source of truth and the snapshot is not loaded; see docs/PERSISTENCE.md for why.

io_uring in containers: Docker's default seccomp profile blocks io_uring on recent versions, and KiviDB then falls back to Tokio. To allow it on a Linux host, run with --security-opt seccomp=unconfined (understand what that permits before using it in production).

Release binaries

Release binaries for Linux (x86_64, aarch64) and macOS (Apple silicon, Intel) are published on GitHub Releases. The latest/download links below always resolve to the newest release; replace latest/download with download/v1.1.0 to pin a version.

# Linux x86_64
curl -LO https://github.com/kividbio/kividb/releases/latest/download/kividb-linux-x86_64.tar.gz
tar xzf kividb-linux-x86_64.tar.gz
./kividb

# Linux aarch64 (an ARMv8.1 CPU or newer: Graviton2 and later, Ampere; not a Raspberry Pi 4)
curl -LO https://github.com/kividbio/kividb/releases/latest/download/kividb-linux-aarch64.tar.gz

# macOS, Apple silicon / Intel
curl -LO https://github.com/kividbio/kividb/releases/latest/download/kividb-darwin-aarch64.tar.gz
curl -LO https://github.com/kividbio/kividb/releases/latest/download/kividb-darwin-x86_64.tar.gz

Each variant other than the default has its name in the file: kividb-lua-linux-x86_64.tar.gz, kividb-tls-…, kividb-full-…. The default variant is also packaged for Linux as kividb_amd64.deb / kividb_arm64.deb and kividb.x86_64.rpm / kividb.aarch64.rpm, built with nfpm from packaging/nfpm.yaml. A SHA256SUMS.txt file lists the checksum of every file in a release.

curl -LO https://github.com/kividbio/kividb/releases/latest/download/kividb_amd64.deb && sudo dpkg -i kividb_amd64.deb
curl -LO https://github.com/kividbio/kividb/releases/latest/download/kividb.x86_64.rpm && sudo rpm -i kividb.x86_64.rpm

Configuration

KiviDB is configured with command-line flags, or with a Redis-style configuration file (one directive per line, such as port 6380 or appendonly yes). The file is read from /etc/kividb/kividb.conf if it exists; --configfile <path> names another one. A flag given on the command line wins over the same setting in the file. Run kividb --help for the full list.

Flag Default Description
--port 6380 Port to listen on
--bind 0.0.0.0 Address to listen on. Setting it explicitly turns off protected mode
--protected-mode <yes|no> yes See Protected mode
--threads 0 (auto) Worker threads; auto is the number of cores minus 2 (all cores below 4)
--databases 16 Number of databases
--dir <path> start directory Where dump.kdb, appendonly.aof and nodes.conf live
--aof off Append-only file persistence
--maxmemory <bytes> 0 (unlimited) Memory limit
--maxmemory-policy noeviction What happens at the limit: noeviction, or the allkeys-* / volatile-* eviction policies (kividb --help lists them)
--loglevel info debug, verbose, notice (or info), warning, nothing
--logfile <path> standard error Write the log to a file
--log-format <text|json> text Log line format
--io-model auto auto, uring or tokio (io_uring is Linux only)
--requirepass <password> none Password for the default user
--aclfile <path> none ACL file to load users from
--replicaof <HOST> <PORT> none Replicate from a primary
--replica-announced-port <port> server port Port announced to the primary via REPLCONF listening-port
--slowlog-log-slower-than <us> off Slowlog threshold in microseconds (0 logs every command)
--slowlog-max-len <n> 128 Slowlog entries kept
--cluster-enabled <yes|no> no Cluster mode: a cluster bus on <port> + 10000, topology in nodes.conf, gossip, failure detection and failover
--cluster-node-timeout <ms> 15000 Time without a reply before a peer is suspected to have failed
--tls-port <port> 0 (off) TLS listener (TLS builds only)
--tls-cert-file, --tls-key-file none Server certificate and key (PEM)
--tls-ca-cert-file none CA that client certificates are checked against
--tls-auth-clients <yes|optional|no> yes Whether clients must present a certificate (only with --tls-ca-cert-file)
--update-check <yes|no> yes The startup update check

TLS

TLS clients connect on a separate port, --tls-port; plain traffic stays on --port.

cargo build --release --features tls
./target/release/kividb --port 6380 --tls-port 6381 --tls-cert-file cert.pem --tls-key-file key.pem
redis-cli --tls -p 6381 --cacert ca.pem   # ca.pem: the CA that signed cert.pem

Client certificates (mutual TLS). With --tls-ca-cert-file ca.pem, clients must present a certificate signed by that CA; others are refused during the handshake. --tls-auth-clients optional accepts clients without a certificate but still refuses an invalid one, and --tls-auth-clients no does not ask for one. With redis-cli: redis-cli --tls -p 6381 --cacert ca.pem --cert client.pem --key client.key.

Clients must use TLS on the TLS port. A plain connection to it (for example redis-cli -p 6381 without --tls) fails the handshake, and the server logs [TLS] handshake failed. For memtier_benchmark, add --tls (and --tls-skip-verify for a self-signed certificate).

Logs and errors

The log goes to standard error, or to --logfile. docs/LOGGING.md describes the log; docs/ERRORS.md explains the warnings, errors and error replies, and what to do about each.

Startup update check

When it starts, a release build of KiviDB makes one HTTPS request to https://github.com/kividbio/kividb/releases/latest, the same page you would open to find the newest release. GitHub answers with a redirect to that release's tag; if it is newer than the running build, KiviDB prints a short notice with the link before the startup banner. Nothing is sent but the request itself, with a User-Agent of kividb/<version>: no host name, configuration, keys, data or identifier. GitHub sees the request's source IP address, as any web server would.

Startup waits at most 1.5 seconds for the reply; a failure is logged at debug level only and never affects clients. Only a version-shaped tag is accepted from the reply, and nothing else from it is printed.

Any one of these turns it off:

  • --update-check no on the command line;
  • update-check no in the configuration file;
  • KIVIDB_NO_UPDATE_CHECK=1 in the environment.

It is also never made by a debug build or when the CI environment variable is set. --update-check-url points it at another https:// address, such as a mirror inside a closed network. docs/UPDATE_CHECK.md has the details.

Contributing

Contributions are welcome. See CONTRIBUTING.md for how to build, test and submit changes. Contributions are accepted under the Contributor License Agreement, which you sign on your first pull request.

Please follow the Code of Conduct. The Changelog lists what changed in each release.

Security

Please do not report security vulnerabilities in public issues. See SECURITY.md for how to report one privately.

License

Copyright (c) 2026 KIVIDB PRIVATE LIMITED.

KiviDB is open source software, licensed under the GNU Affero General Public License, version 3 (AGPL-3.0-only), an OSI-approved license. You may use, modify and redistribute it under its terms. See NOTICE.

Using KiviDB does not put your application under the AGPL. An application that talks to KiviDB over the network, through any Redis client, is a separate program: you can run an unmodified KiviDB as your database, in any product, open or closed, commercial or not, with no obligation on your application's code. The AGPL asks for one thing beyond the GPL: if you modify KiviDB itself and let others use your modified version over a network (for example, as a hosted service), you must offer them the source code of your modified KiviDB.

Commercial license. KIVIDB PRIVATE LIMITED owns the copyright in KiviDB and also offers it under a commercial license, for organizations that cannot use AGPL software or that want to modify or embed KiviDB without publishing their changes. Write to [email protected].

Our commitment. Every version of KiviDB we release under the AGPLv3 stays available under the AGPLv3. The Contributor License Agreement lets us offer the commercial license alongside it; it is not a way to take the open source version away.

FAQ

  • Can I use KiviDB as the database of my closed-source or commercial application? Yes. Your application connects to KiviDB over the network; it is not a derivative of KiviDB, and the AGPL places no obligation on it.
  • Can I run KiviDB as a service for my own users or customers? Yes. If you run it unmodified, you have nothing to publish. If you modify KiviDB and offer that modified version over a network, you must offer its source to the users of that service.
  • Do client libraries or my configuration count as modifications? No. Redis clients, configuration files, and scripts and functions you send to KiviDB are not part of KiviDB.
  • My organization does not allow AGPL software. The commercial license is for that case: [email protected].

Trademarks

Redis® is a registered trademark of Redis Ltd. Any rights therein are reserved to Redis Ltd. Any use by KiviDB is for referential purposes only and does not indicate any sponsorship, endorsement or affiliation between Redis and KiviDB. KiviDB is not affiliated with Redis Ltd. Other names mentioned are trademarks of their respective owners.

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