meebis

A fast, disposable, in-memory Redis-compatible server in Rust — for ephemeral local work.

Spin one up per git worktree, point a couple of processes at it, then throw it away. It boots clean every time, keeps everything in RAM, and forgets it all on exit. There is no config file and nothing to clean up. To skip the server lifecycle entirely, meebis run -- npm test lends one command an instance and takes it away again — see meebis run. If you want the keyspace to survive a restart, --dumpfile reads and writes Redis' own RDB snapshot format — see Snapshots.

• Fast — matches real Redis throughput (~110–130k ops/sec single-threaded, sub-millisecond latency).
• Tiny — a sub-1 MB binary using ~2 MB RAM per instance idle, so you can run dozens at once without noticing (see Footprint & performance).
• Compatible — speaks RESP2 and RESP3 and a broad slice of the Redis command surface. redis-cli, redis-py, and other standard client libraries just work, verified byte-for-byte against Redis 7.2.
• Disposable — clean on boot, gone on exit, unless you hand it a snapshot to load and save. Not durable either way, by design.

It is not a Redis replacement for production. It's a dev tool.

Install

Homebrew (macOS & Linux):

brew install mileszim/tap/meebis

npm — nothing to install if you only want to run one:

npx meebis                      # fetch and run, no install step
npm install --save-dev meebis   # or pin it into a project

Handy as a package.json script, so a checkout comes with its own Redis:

"scripts": {
  "redis": "meebis --port 6400"
}

Shell installer (macOS & Linux) — downloads the right prebuilt binary for your platform:

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/mileszim/meebis/releases/latest/download/meebis-installer.sh | sh

Cargo:

cargo binstall meebis           # prebuilt binary, no compile (needs cargo-binstall)
cargo install meebis            # build from source (crates.io)

mise or asdf — pin a version per project, alongside your other tools:

mise use github:mileszim/meebis@0.12.0        # mise, no plugin needed

asdf plugin add meebis https://github.com/mileszim/meebis.git
asdf install meebis 0.12.0                    # asdf

See mise & asdf for .tool-versions, mise.toml, and the @latest caveat.

Devcontainer — add it to devcontainer.json, see Devcontainer:

"features": { "ghcr.io/mileszim/meebis/meebis:1": {} }

Docker (linux/amd64 & linux/arm64) — see Docker for Compose:

docker run --rm -p 6379:6379 ghcr.io/mileszim/meebis

Prebuilt binaries for macOS and Linux (arm64 & x86_64) are attached to every release as .tar.xz archives, with sha256 checksums. The shell and npm installers both just fetch the right one of these — there is no compile step and no build toolchain needed.

From a local checkout:

cargo build --release           # ./target/release/meebis
cargo install --path .          # installs `meebis` into your cargo bin

Run

meebis                          # listen on 127.0.0.1:6379
meebis --port 6400              # pick a port (the main thing you'll configure)
meebis --port 0                 # let the OS choose a free port (printed on boot)
meebis --requirepass hunter2    # require AUTH
meebis run -- npm test          # or skip all that: see `meebis run` below

meebis 0.1.0 ready on 127.0.0.1:6400 (pid 12345) — in-memory, no persistence

Then connect as you would to Redis:

redis-cli -p 6400 set hello world
redis-cli -p 6400 get hello

import redis
r = redis.Redis(port=6400)      # redis-py, node-redis, go-redis, lettuce, ...
r.set("hello", "world")

Options

Flag	Default	Description
-p, --port <PORT>	6379	Port to listen on (0 lets the OS pick a free one)
--bind <ADDR>	127.0.0.1	Address to bind
--unixsocket <PATH>	(none)	Listen on a unix socket; on its own it replaces the port (see Unix sockets)
--port-file <PATH>	(none)	Write the actual listen port to <PATH> on boot
--requirepass <PASS>	(none)	Require AUTH before most commands
--maxclients <N>	10000	Maximum simultaneous connections
--databases <N>	16	Number of SELECTable databases
--dumpfile <PATH>	(none)	Load this RDB snapshot at boot, write it on exit (see Snapshots)
--dir <DIR> / --dbfilename <NAME>	. / dump.rdb	Redis' two-part spelling of --dumpfile
--seed <PATH>	(none)	Load this RDB snapshot at boot and never write to it (see Seeding from a fixture)
--dumpfile-strict	(off)	Refuse to start when the snapshot asked for cannot be loaded
--verbose	(off)	Log every command and reply (see Verbose logging)
--loglevel <LEVEL>	notice	nothing/warning/notice/verbose/debug; verbose and debug are the same as --verbose
--env <NAME>	(none)	meebis run only: also set <NAME> to the connection URL (repeatable)
-h, --help / -v, --version		Print help / version

Multiple processes can connect to the same instance concurrently and share the keyspace, including pub/sub and transactions.

meebis run — one command, one instance

Most of the time you don't want to manage a server at all; you want a command to have a Redis. meebis run starts one, runs the command against it, and shuts it down when the command exits:

meebis run -- npm test

The command is handed its connection details in the environment:

Variable	Example
REDIS_URL	redis://127.0.0.1:54312
REDIS_HOST	127.0.0.1
REDIS_PORT	54312

Without an explicit --port the OS picks a free one, and the port is resolved before the command starts — so there is no startup race to lose, no port file to poll, and no collision when several run at once:

meebis run -- pytest
meebis run -- ./bin/rails test
meebis run --requirepass hunter2 -- ./my-app

That makes it safe to run one per worktree, or several in the same CI job, with nothing left behind either way. Server options go before the --; everything after it belongs to the command.

meebis run exits with the command's own exit status, so it drops into a test script or a CI step without changing what "failed" means. For an app that reads something other than REDIS_URL, name the variable you want:

meebis run --env CACHE_URL --env SIDEKIQ_REDIS_URL -- ./bin/dev

To skip ports altogether, --unixsocket swaps the address for a path — see Unix sockets.

Ctrl-C does what you would expect: the command is signalled, gets its own chance to shut down, and meebis follows it out — writing the snapshot on the way, if you passed --dumpfile. A second Ctrl-C stops asking nicely. meebis' own output goes to stderr in this mode, so the command keeps stdout to itself and meebis run -- ... > out.txt captures only the command's output.

A long-lived instance per worktree

When you want a server that outlives any single command — one per worktree that several processes share — run it directly. Instead of hand-assigning a port to each worktree, let the OS pick a free one with --port 0 and record it with --port-file, so your app and tests can find it:

meebis --port 0 --port-file .meebis-port
export REDIS_URL="redis://127.0.0.1:$(cat .meebis-port)"

The port is written to the file atomically once meebis has bound, and rewritten on each boot — so a reader never sees a half-written value.

With direnv

A .envrc is a natural place to wire this in: the worktree gets a Redis on the first cd into it, and every shell there sees the same one.

# .envrc — one meebis for this worktree, started on the first `cd` in.
#
# direnv re-runs this whenever it reloads, so it must be idempotent: start a
# server only when one is not already answering.
meebis_dir="$PWD/.meebis"
mkdir -p "$meebis_dir"

# Asking the server whether it is there beats checking a pid: a pid can be
# recycled onto something unrelated, and what matters is that a Redis answers.
meebis_answering() {
  [ -s "$meebis_dir/port" ] || return 1
  (exec 3<>"/dev/tcp/127.0.0.1/$(cat "$meebis_dir/port")") 2>/dev/null
}

if ! meebis_answering; then
  rm -f "$meebis_dir/port"
  nohup meebis --port 0 --port-file "$meebis_dir/port" >"$meebis_dir/log" 2>&1 &
  echo $! >"$meebis_dir/pid"
  # meebis writes the port file only once it has bound, so waiting for it is
  # waiting for "ready", not merely for "spawned".
  for _ in $(seq 1 50); do
    if meebis_answering; then break; fi
    sleep 0.1
  done
fi

if meebis_answering; then
  export REDIS_HOST=127.0.0.1
  export REDIS_PORT="$(cat "$meebis_dir/port")"
  export REDIS_URL="redis://$REDIS_HOST:$REDIS_PORT"
  # A restart picks a new port; this makes direnv notice instead of replaying a
  # stale one from its cache.
  if declare -F watch_file >/dev/null; then watch_file "$meebis_dir/port"; fi
else
  echo "meebis: did not come up — see $meebis_dir/log" >&2
fi

Then direnv allow, and add .meebis/ to .gitignore.

Two things this deliberately does not pretend to do:

• It does not stop the server when you leave. direnv has no reliable teardown hook, so the instance outlives the shell — which is usually what you want for a worktree, at about 2 MB. kill $(cat .meebis/pid) when you're done with the worktree, or just delete the worktree and let it go.
• direnv caches the environment, so if the server dies while you are away, the variables it exported can outlive it. direnv reload starts a fresh one.

If neither of those appeals, a test command doesn't need any of this — meebis run -- <command> starts and stops its own instance, which is why it is the better default for anything that isn't a long-lived shell.

With a Procfile

If the worktree already runs its processes under foreman, overmind or hivemind, meebis is just another line, and the supervisor handles the lifecycle:

redis: meebis --port 6400
web:   ./bin/dev

Pick a distinct port per worktree, or use --unixsocket .meebis/redis.sock and skip the question entirely.

Unix sockets

A port has to be allocated, recorded, and looked up. A socket path doesn't — it's derivable from the worktree itself, which makes it the simpler address for exactly the case meebis is built for:

meebis --unixsocket .meebis/redis.sock

meebis 0.9.0 ready on .meebis/redis.sock (pid 12345) — in-memory, no persistence

--unixsocket on its own replaces the TCP port entirely. That is the point: leaving 6379 bound as well would reintroduce the collision the socket was chosen to avoid, so twenty worktrees can each run that exact command with nothing to coordinate. Pass --port as well to listen on both:

meebis --unixsocket .meebis/redis.sock --port 6400

Clients dial it the way they dial Redis:

redis-cli -s .meebis/redis.sock ping

r = redis.Redis(unix_socket_path=".meebis/redis.sock")
r = redis.from_url("unix:///abs/path/to/redis.sock")   # or by URL

meebis run works the same way, and hands down what there is to hand down — REDIS_URL as unix://<path> and REDIS_SOCKET as the bare path. REDIS_HOST and REDIS_PORT are unset in this mode rather than left holding whatever they held before, so an app that needs a host:port fails where the mistake is instead of quietly connecting to a different Redis:

meebis run --unixsocket .meebis/redis.sock -- npm test

The socket file is removed on a clean exit. If meebis is killed outright it stays behind, so the next boot clears it — but only after checking that nobody is answering on it, which means a second server can never displace a running one. A path holding something that isn't a socket is refused, never deleted.

Unix only, for the obvious reason; on Windows --unixsocket is rejected at startup.

Verbose logging

To see what your app is actually doing to Redis, start with --verbose:

meebis --port 6400 --verbose

Every command in and reply out is logged to stdout, tagged with the client id that sent it and how long it took:

meebis 0.5.0 ready on 127.0.0.1:6400 (pid 12345) — in-memory, no persistence
2026-08-13T18:04:21.512Z * verbose logging on — every command and reply is logged
2026-08-13T18:04:21.583Z #1 * connected from 127.0.0.1:52814
2026-08-13T18:04:21.583Z #1 > SET greeting "hello world" EX 30
2026-08-13T18:04:21.583Z #1 < OK (21µs)
2026-08-13T18:04:21.584Z #1 > LRANGE queue 0 -1
2026-08-13T18:04:21.584Z #1 < [a, b, c] (6µs)
2026-08-13T18:04:21.585Z #1 > INCR greeting
2026-08-13T18:04:21.585Z #1 < (error) ERR value is not an integer or out of range (4µs)
2026-08-13T18:04:21.612Z #2 * connected from 127.0.0.1:52815
2026-08-13T18:04:21.612Z #2 > SUBSCRIBE news
2026-08-13T18:04:21.612Z #2 < (push) [subscribe, news, (integer) 1] (5µs)
2026-08-13T18:04:21.640Z #2 < (push) [message, news, hello]
2026-08-13T18:04:21.641Z #1 * disconnected

> is a command coming in, < a reply going out, * a connection event (connected, disconnected, parked on a blocking command). Timestamps are UTC. Values are quoted the way redis-cli shows them, long values and big replies are truncated with a note of what was dropped, and passwords (AUTH, HELLO ... AUTH, CONFIG SET requirepass) are logged as <redacted>.

Commands a Lua script issues are traced too, tagged (lua), so an EVAL shows its work instead of just its final reply:

2026-08-13T18:04:22.100Z #3 > EVAL "redis.call('set', KEYS[1], ARGV[1]) return redis.call('get', KEYS[1])" 1 k v
2026-08-13T18:04:22.100Z #3 > (lua) SET k v
2026-08-13T18:04:22.100Z #3 < (lua) OK (49µs)
2026-08-13T18:04:22.100Z #3 > (lua) GET k
2026-08-13T18:04:22.100Z #3 < (lua) v (2µs)
2026-08-13T18:04:22.101Z #3 < v (312µs)

It can also be flipped on and off on a running server, so you can leave a long-lived instance quiet and only trace the moment you care about:

redis-cli -p 6400 config set loglevel verbose   # start logging
redis-cli -p 6400 config set loglevel notice    # stop

Logging is off by default and gated on a single atomic load, so a quiet server runs at full speed; with it on, expect to give up some throughput to the formatting and writing (~15% under redis-benchmark).

Docker

Multi-arch images (linux/amd64, linux/arm64) are published to the GitHub Container Registry on every release:

docker run --rm -p 6379:6379 ghcr.io/mileszim/meebis

Tag	Points at
0.8.0	that exact release
0.8	the newest patch of that minor
latest	the tip of main
main, sha-<short>	the tip of main, and each individual commit

latest follows main rather than the newest release, so pin to 0.8 (or a full version) for anything you want to stay put.

The image is built FROM scratch around a statically linked musl binary — no shell, no package manager, nothing but meebis, at roughly the size of the binary itself. The entrypoint already passes --bind 0.0.0.0, so the server is reachable from outside the container; any flags you add are appended to it:

docker run --rm -p 6400:6379 ghcr.io/mileszim/meebis --requirepass hunter2 --verbose

Compose

meebis is a drop-in swap for a redis service. The whole point is that there is nothing else to configure — no volume, no command: override, no health-check wait, because a fresh instance is the desired state every time:

services:
  redis:
    image: ghcr.io/mileszim/meebis:0.8
    ports: ["6379:6379"]

  app:
    build: .
    environment:
      REDIS_URL: redis://redis:6379
    depends_on: [redis]

Two things to know, both consequences of the scratch image:

• No in-container health check. There is no shell and no redis-cli inside, so the usual test: ["CMD", "redis-cli", "ping"] will not run. meebis binds its port before it prints its banner and does no startup work unless you pass --dumpfile, so plain depends_on is normally enough; if you need a real gate, run the probe from the depending service instead.
• docker exec gets you nothing. Use redis-cli from the host (or another service) against the published port.

Snapshots in a container

Nothing is written to disk by default. To carry a keyspace across container restarts, mount a directory and point --dumpfile into it:

docker run --rm -p 6379:6379 -v "$PWD/.meebis:/data" \
  ghcr.io/mileszim/meebis --dumpfile /data/dump.rdb

docker stop sends SIGTERM, which meebis catches and snapshots on; docker kill does not. See Snapshots for what that file is and is not.

mise & asdf

If your project already pins its toolchain, meebis can be one more line in it — which is the natural fit, since the audience for a per-worktree Redis is largely the audience already running a version manager.

mise

No plugin required: mise can install straight from the release assets.

mise use github:mileszim/meebis@0.12.0

# mise.toml
[tools]
"github:mileszim/meebis" = "0.12.0"

@latest also works, with one wrinkle worth knowing: mise's minimum_release_age setting hides releases newer than a few days, so immediately after a release @latest still resolves to the previous one. Pin the version, or clear the setting, if that matters to you.

meebis also hosts an asdf plugin (below) that mise can use instead, if you would rather refer to it by bare name:

mise plugin add meebis https://github.com/mileszim/meebis.git
mise use meebis@0.12.0

asdf

The plugin lives in this repository rather than a separate asdf-meebis one, so there is nothing extra to trust:

asdf plugin add meebis https://github.com/mileszim/meebis.git
asdf install meebis 0.12.0
asdf set meebis 0.12.0          # writes .tool-versions

# .tool-versions
meebis 0.12.0

It installs the prebuilt binary for your platform (macOS and Linux, arm64 and x86_64) and checks it against the sha256 published beside it. asdf install meebis latest picks the newest release.

Neither route builds from source, so neither needs a Rust toolchain.

Devcontainer

There is a devcontainer feature that puts meebis in the image:

{
  "image": "mcr.microsoft.com/devcontainers/base:debian",
  "features": {
    "ghcr.io/mileszim/meebis/meebis:1": {}
  }
}

Pin the version if you want to:

"features": {
  "ghcr.io/mileszim/meebis/meebis:1": { "version": "0.12.0" }
}

It installs the binary and starts nothing — meebis has no daemon, no data directory, and no config, so there is nothing to keep running between uses. Wrap whatever needs a Redis:

"postCreateCommand": "meebis run -- npm test"

...or start one for the life of the container, if several processes need to share it:

"postStartCommand": "nohup meebis --port 6379 > /tmp/meebis.log 2>&1 &"

The base image needs glibc 2.34 or newer — Debian 12+, Ubuntu 22.04+ — since that is what the release binaries are linked against. On an older base, or on Alpine, the feature stops during the build and says so rather than installing something that cannot run. For a musl or minimal environment, use the Docker image instead: it is statically linked and has no such requirement.

Claude Code plugin

Coding agents working in parallel worktrees hit the same problem this whole tool is about: each one needs its own Redis, and none of them should be sharing a keyspace. There is a plugin in claude-code/ for that:

/plugin marketplace add mileszim/meebis
/plugin install meebis@meebis

It ships a skill that tells Claude to reach for meebis run -- <command>, where to find a running instance's port, and — the part that saves the most time — which Redis features meebis does not implement, so a missing XREADGROUP isn't mistaken for a bug in the code under test.

It also ships session hooks that give a project its own instance for as long as a session lasts. Those are opt-in per project, so installing the plugin does not start servers everywhere:

mkdir .meebis            # this project wants an instance
echo .meebis/ >> .gitignore

Every Claude Code session in that project then gets a server on an OS-assigned port, recorded in .meebis/port; sessions in the same project share one, and it is stopped when the last of them ends. See the plugin README for the details.

Supported commands

Verified byte-for-byte against Redis 7.2 for the cases in the test suite.

• Strings — GET SET (EX/PX/EXAT/PXAT/NX/XX/GET/KEEPTTL) SETNX SETEX PSETEX GETSET GETDEL GETEX APPEND STRLEN INCR DECR INCRBY DECRBY INCRBYFLOAT MGET MSET MSETNX GETRANGE SETRANGE SUBSTR
• Bitmaps — SETBIT GETBIT BITCOUNT BITPOS BITOP
• Keys — DEL UNLINK EXISTS EXPIRE PEXPIRE EXPIREAT PEXPIREAT TTL PTTL EXPIRETIME PEXPIRETIME PERSIST KEYS SCAN TYPE RENAME RENAMENX RANDOMKEY TOUCH COPY MOVE
• Hashes — HSET HMSET HSETNX HGET HMGET HDEL HGETALL HKEYS HVALS HLEN HEXISTS HSTRLEN HINCRBY HINCRBYFLOAT HSCAN HRANDFIELD
• Lists — LPUSH RPUSH LPUSHX RPUSHX LPOP RPOP LLEN LRANGE LINDEX LSET LREM LTRIM LINSERT LPOS RPOPLPUSH LMOVE
• Sets — SADD SREM SMEMBERS SISMEMBER SMISMEMBER SCARD SPOP SRANDMEMBER SMOVE SUNION SINTER SDIFF SUNIONSTORE SINTERSTORE SDIFFSTORE SINTERCARD SSCAN
• Sorted sets — ZADD (NX/XX/GT/LT/CH/INCR) ZREM ZSCORE ZMSCORE ZCARD ZCOUNT ZINCRBY ZRANK ZREVRANK ZRANGE ZREVRANGE ZRANGEBYSCORE ZREVRANGEBYSCORE ZRANGEBYLEX ZREVRANGEBYLEX ZLEXCOUNT ZPOPMIN ZPOPMAX BZPOPMIN BZPOPMAX ZREMRANGEBYRANK ZREMRANGEBYSCORE ZSCAN ZRANDMEMBER
• Streams — XADD (*/<ms>-*/explicit IDs, NOMKSTREAM, MAXLEN/MINID with ~/= and LIMIT) XLEN XRANGE XREVRANGE XREAD (COUNT, BLOCK, $ snapshot) XDEL XTRIM
• Scripting — EVAL EVALSHA EVAL_RO EVALSHA_RO SCRIPT LOAD/EXISTS/FLUSH, with sandboxed Lua 5.1 (Redis' scripting version), redis.call/pcall/ error_reply/status_reply/sha1hex/log, and the cjson/cmsgpack/bit libraries. Scripts run atomically under a single held keyspace lock — the same guarantee Redis' single thread provides.
• Pub/Sub — SUBSCRIBE UNSUBSCRIBE PSUBSCRIBE PUNSUBSCRIBE PUBLISH PUBSUB
• Transactions — MULTI EXEC DISCARD WATCH UNWATCH
• Connection — PING ECHO HELLO AUTH SELECT QUIT RESET CLIENT
• Server — INFO CONFIG GET/SET DBSIZE FLUSHDB FLUSHALL SWAPDB TIME COMMAND DEBUG OBJECT MEMORY DBSIZE SHUTDOWN LOLWUT (and SAVE, BGSAVE, etc. as accepted no-ops)

Keys and values are binary-safe. EXPIRE and friends work with the full NX/XX/GT/LT option set. Expired keys are removed lazily on access and by a once-per-second sweep.

Numbered databases

meebis provides Redis' 16 SELECTable databases (--databases N to change the count). They are fully independent — KEYS, DBSIZE, RANDOMKEY, FLUSHDB and WATCH are all scoped to the selected one, while FLUSHALL clears every database. Keys cross between them with MOVE key db and COPY src dst DB n, both of which carry the TTL over, and SWAPDB exchanges two wholesale.

Pub/Sub is global, as in Redis: a message published on one database is delivered to subscribers on all of them.

Snapshots (--dumpfile)

By default nothing touches the disk. Point meebis at a dump file and it will load that snapshot at boot and write it back on the way out:

meebis --port 6400 --dumpfile .meebis/dump.rdb

meebis 0.7.0 ready on 127.0.0.1:6400 (pid 12345) — in-memory, snapshotting to .meebis/dump.rdb

The file is Redis' own RDB format, not a meebis invention, so it moves in both directions:

# Seed a worktree from a snapshot a real Redis wrote
redis-cli -p 6379 save
meebis --port 6400 --dumpfile /var/lib/redis/dump.rdb

# ...or hand meebis' state to a real redis-server
redis-cli -p 6400 shutdown
redis-server --dir .meebis --dbfilename dump.rdb

Redis' own --dir / --dbfilename spelling works too, for tooling that already sets them, and CONFIG GET dir dbfilename reports the real values.

The snapshot is written on a clean exit (SIGINT, SIGTERM, SHUTDOWN) and on demand via SAVE / BGSAVE. meebis is single-threaded, so BGSAVE writes synchronously and then returns Redis' reply — the file is already on disk when the client hears back.

This is not durability. The keyspace still lives only in RAM, there are no periodic save points, and a kill -9 loses everything since the last save. What it buys is carrying state across a restart or between servers.

A few things worth knowing:

• Reading accepts anything; writing stays simple. meebis reads every encoding across RDB versions 1–11 — listpacks, quicklists, ziplists, intsets, LZF-compressed strings — because Redis picks those and meebis has to cope. It writes only the flat, oldest-spelling encodings, which Redis 7.2+ still loads. Dumps are therefore a little larger than Redis' own.
• A dump that won't load doesn't block boot. meebis logs the reason, renames the unreadable file to <name>.unreadable-<pid> so the next save can't destroy it, and starts with an empty keyspace. --dumpfile-strict makes it exit instead, the way Redis does.
• Consumer groups and functions are dropped, with a warning, since meebis models neither. Everything else — every value type, TTLs, and all --databases — round-trips.
• DEBUG RELOAD runs the whole keyspace through the same codec in memory, which is how the test suite checks the two halves agree.

Seeding from a fixture (--seed)

--dumpfile reads and writes the same path, which is wrong for the obvious worktree pattern — "every instance starts from fixtures/golden.rdb" — because every instance would then overwrite the fixture on the way out, and the third worktree would inherit whatever the second one happened to leave behind.

--seed is the read-only half:

meebis --seed fixtures/golden.rdb

meebis 0.9.0 ready on 127.0.0.1:6379 (pid 12345) — in-memory, seeded from fixtures/golden.rdb (read-only)

The snapshot is loaded at boot and the file is never written to again — not on exit, not on SHUTDOWN, not on SAVE/BGSAVE (which still reply OK, exactly as they do for an instance with no dump file at all). Run twenty of them against one fixture and it is still byte-for-byte the file you committed.

It also declines the one other thing --dumpfile does to its file: a dump that won't load is renamed to <name>.unreadable-<pid> so the next save can't destroy it, but a seed that won't load is left alone — it isn't meebis' file to move, and twenty instances must not race to shuffle it around. meebis warns and starts empty instead.

--seed and --dumpfile (and its --dir/--dbfilename spelling) are mutually exclusive; they say opposite things about the same path. --dumpfile-strict applies to either, and for a seed it also makes a missing file fatal — an absent dump file is an ordinary first boot, while an absent fixture is a path that doesn't say what its author thought it said.

Deliberately not supported

This is a small dev tool, so some Redis features are intentionally absent:

• Durable persistence — --dumpfile reads and writes RDB snapshots, but there are no save points, no AOF, and no crash safety.
• Stream consumer groups (XGROUP, XREADGROUP, XACK, XPENDING, XCLAIM, XAUTOCLAIM) — XADD/XREAD/XRANGE/XTRIM/XDEL are supported; groups are not.
• List-blocking commands (BLPOP, BRPOP, BLMOVE, BLMPOP, BZMPOP) — BZPOPMIN/BZPOPMAX and XREAD BLOCK are supported; the rest are not yet.
• HyperLogLog, GEO, and cluster mode.

Both RESP2 and RESP3 are supported — clients using either (e.g. redis-py's default RESP3, or redis-cli's RESP2) work without configuration.

WATCH is implemented by fingerprinting watched keys and aborting EXEC if any changed — correct for optimistic-locking patterns, without per-key versioning.

Footprint & performance

meebis is built to be cheap enough to run many instances at once. Measured with a --release build on an Apple Silicon laptop (12 cores):

Metric	meebis	Notes
Binary size	~860 KB	one small binary, stripped
Idle memory (RSS)	~2 MB per instance	one OS thread per process
20 instances at once	~40 MB total	dozens is a non-issue
Throughput	~110–130k ops/sec	redis-benchmark -n 100000 -c 50
Latency	~0.2 ms p50

Command throughput and latency track real Redis 7.2 on the same machine — both execute commands on a single thread — so meebis is not a local-dev bottleneck. A side-by-side redis-benchmark run:

              meebis        redis 7.2
SET       121,212 rps      118,906 rps
GET       114,025 rps      123,001 rps
INCR      111,857 rps      125,471 rps
RPUSH     126,422 rps      123,305 rps
SADD      128,041 rps      123,001 rps
HSET      116,959 rps      104,822 rps
ZADD      121,951 rps      113,250 rps

Absolute numbers vary with hardware; the point is that the memory footprint stays flat whether you run one instance or twenty, and speed is on par with Redis itself.

How it works

One tokio current-thread runtime per process (a single OS thread — hence the tiny footprint), with all command execution serialized behind one mutex, just like Redis. Each connection is an async task; pub/sub messages are pushed to subscribers over in-process channels.

Lua scripts (EVAL) run under an embedded Lua 5.1 (Redis' scripting version), holding that same keyspace mutex for the whole script — so each redis.call inside a script re-enters the dispatcher against the locked keyspace with no opportunity for another connection to interleave. Blocking commands (BZPOPMIN, XREAD BLOCK) release the mutex and park on a shared Notify that every write wakes, so idle waiters cost zero CPU.

Development

cargo test          # unit tests for the protocol, glob matching, expiry, zsets, sha1
cargo clippy        # clean

The full Redis compatibility suite lives in tests/compat/ — RESP2 fixtures diffed byte-for-byte against a real redis-server, plus a RESP3 parity check via redis-py. Run it with bash tests/compat/run.sh (needs redis-server and redis-cli on PATH; the RESP3 stage needs python3 with the redis package).

License

MIT — see LICENSE.