Leaderboards

The leaderboard pattern

A game or app leaderboard needs three things: store a score, rank players, and add points over time. Redis Sorted Sets handle all three natively with O(log N) writes and O(log N + M) range reads.

Step 1 — Add initial scores with ZADD

Start by inserting players and their scores. Scores are float64, so they can represent points, percentages, timestamps, or any numeric ranking value.

127.0.0.1:6379> ZADD game:lb 3200 "alice" 4100 "bob" 1750 "carol" 5800 "dave" 2900 "eve"
(integer) 5

ZADD game:lb 3200 "alice" 4100 "bob" 1750 "carol" 5800 "dave" 2900 "eve"

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Step 2 — Fetch the top 10 with ZREVRANGE

ZREVRANGE key 0 9 WITHSCORES returns the top 10 players in descending score order. The indices are rank offsets, so 0 9 always means positions 1 through 10.

127.0.0.1:6379> ZREVRANGE game:lb 0 9 WITHSCORES
1) "dave"
2) "5800"
3) "bob"
4) "4100"
5) "alice"
6) "3200"
7) "eve"
8) "2900"
9) "carol"
10) "1750"

ZREVRANGE game:lb 0 9 WITHSCORES

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Step 3 — Look up a player’s rank with ZREVRANK

ZREVRANK key member returns the 0-based rank in descending order — 0 is first place. Add 1 to get a human-friendly rank.

127.0.0.1:6379> ZREVRANK game:lb "alice"
(integer) 2
127.0.0.1:6379> ZREVRANK game:lb "carol"
(integer) 4
127.0.0.1:6379> ZSCORE game:lb "alice"
"3200"

ZREVRANK game:lb "alice"
ZREVRANK game:lb "carol"
ZSCORE game:lb "alice"

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Step 4 — Award points with ZINCRBY

When a player earns more points, use ZINCRBY to atomically add to their existing score. No read-modify-write cycle needed.

127.0.0.1:6379> ZINCRBY game:lb 1500 "carol"
"3250"
127.0.0.1:6379> ZINCRBY game:lb 800 "alice"
"4000"
127.0.0.1:6379> ZREVRANGE game:lb 0 4 WITHSCORES
1) "dave"
2) "5800"
3) "bob"
4) "4100"
5) "alice"
6) "4000"
7) "carol"
8) "3250"
9) "eve"
10) "2900"

ZINCRBY game:lb 1500 "carol"
ZINCRBY game:lb 800 "alice"
ZREVRANGE game:lb 0 4 WITHSCORES

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Full leaderboard workflow in one paste

127.0.0.1:6379> ZADD lb 3200 "alice" 4100 "bob" 1750 "carol" 5800 "dave" 2900 "eve"
(integer) 5
127.0.0.1:6379> ZREVRANGE lb 0 9 WITHSCORES
1) "dave"
2) "5800"
3) "bob"
4) "4100"
5) "alice"
6) "3200"
7) "eve"
8) "2900"
9) "carol"
10) "1750"
127.0.0.1:6379> ZREVRANK lb "carol"
(integer) 4
127.0.0.1:6379> ZINCRBY lb 2500 "carol"
"4250"
127.0.0.1:6379> ZREVRANK lb "carol"
(integer) 1

ZADD lb 3200 "alice" 4100 "bob" 1750 "carol" 5800 "dave" 2900 "eve"
ZREVRANGE lb 0 9 WITHSCORES
ZREVRANK lb "carol"
ZINCRBY lb 2500 "carol"
ZREVRANK lb "carol"

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🟥 Sorted Sets are the canonical leaderboard structure

Every operation you need for a leaderboard is a single Redis command: insert or update a score (ZADD), award points (ZINCRBY), fetch the top N (ZREVRANGE 0 N-1 WITHSCORES), and find a player’s rank (ZREVRANK). All run in O(log N) or O(log N + M). No JOIN, no ORDER BY, no secondary index needed — the data structure maintains sorted order for you at all times.

Which command fetches the top 10 players in descending score order?

ZRANGE lb 0 9 WITHSCORES ZREVRANGE lb 0 9 WITHSCORES ZSCORE lb 0 9 ZREVRANK lb 0 9

ZREVRANK returns 0 for which player?

The player with the lowest score The player with the highest score The player added first The player with the median score

Why is ZINCRBY preferred over ZADD when awarding points?

ZINCRBY is faster than ZADD ZINCRBY atomically adds to the current score without a read-modify-write ZADD cannot update existing members ZINCRBY works on Sets not Sorted Sets

If carol's current score is 1750 and you run ZINCRBY lb 2500 carol, what is her new score?

2500 1750 4250 750

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