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

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)

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.

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
--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
--dumpfile-strict	(off)	Refuse to start when a dump exists but 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

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. A .envrc (direnv) or a Procfile is a natural place to wire this into your dev loop.

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.

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.

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.