Every key in one slot
A constant hash tag puts the whole keyspace on a single node
{app}:user:1
{app}:user:2
{app}:user:3
{app}:user:4
{app}:user:5
{app}:user:6Redis Key Name Validator
Paste key names, one per line. Redis accepts almost any byte sequence as a key, so nothing here is about validity: it is about names that work in a shell, in a log, and on a cluster.
Paste below, or drop a file anywhere on this panel
Or drop a file anywhere on this panel. Nothing is uploaded: the analysis runs in this tab.
The answer appears here
Paste on the left and press Check. Nothing leaves this tab.
Formatted
Results
Nothing else to flag.
No formatting problems, and nothing the rules object to. Worth remembering what that covers: this reads the file you pasted, not the account or cluster it will be applied to.
No finding matches that filter.
Examples
Real input you can load into the tool above. Each one shows a different thing going wrong, because that is what the tool is for.
A key with a space
Legal, and painful in every shell and every log
user:1 a key with spaces session:abc
Common mistakes
These are the ones that fail silently. The config is accepted, nothing raises an error, and the consequence arrives later.
Using one hash tag for every key
It forces the whole keyspace into one slot on one node, so the cluster cannot balance.
Instead:Tag by the group that must stay together, such as a tenant id.
Building a key from unsanitised user input
A newline or a null byte produces a key nobody can see in any diagnostic.
Instead:Strip control characters, or hash the variable part.
Assuming {} makes a hash tag
An empty brace pair is not a tag, and neither is an unclosed brace. The whole key is hashed instead.
Instead:Put a real value between the braces.
Mixing colons, dots and dashes as separators
Prefix patterns written for one convention silently miss the others.
Instead:Pick one separator and use it everywhere.
Redis accepts any bytes, and that is the problem
A key can contain a newline, a space or a null byte and Redis will store and return it perfectly. Everything else in your stack will not cope as well.
Control characters make a key invisible in every diagnostic
A key with a trailing newline looks identical to one without in redis-cli output, in MONITOR, in SLOWLOG and in your logs. It stores and retrieves correctly, so the bug is a lookup that fails for no visible reason, and a difference nobody can see is one nobody can fix.
A hash tag decides which node the key lives on
Only the text between the first brace and the first closing brace after it is hashed. That is what makes multi-key commands possible on a cluster. Using the same tag for every key puts the entire keyspace on one node, so the cluster cannot balance and one node carries all the traffic.
Braces have three rules and two of them surprise people
An empty pair is not a tag. An unclosed brace is not a tag. Only the first brace, paired with the first closing brace after it, counts. A key that looks tagged may not be, and it will land in a different slot than the one you intended.
Key names cost memory, once per key
The name is stored in full, in memory, for every key, and it is copied into every reply and every log line. At tens of millions of keys the names alone become a measurable fraction of the dataset. The limit is 512 MB, so this is a cost question rather than a validity one.
Mixed separators break prefix matching
A SCAN pattern written for one convention silently misses keys following another. Pick one, conventionally the colon, and use it everywhere.
Related redis tools
Redis Hash Tag Tester Will these keys survive a multi-key command? redis.conf Validator Will Redis start with this file? Redis ACL Validator Find the rule that does nothing Redis Key Count to Memory The fixed cost per key Redis Keyspace Prefix Analyzer Which key family is growing Redis Hash Slot Calculator Which of the 16,384 slots does this key land in?
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