A causality-encoding engine written in TypeScript and C++ to build high-performance, conflict-free replicated data types for use on the web.
Sequencer provides a deterministic total ordering for distributed data. It allows independently operating replicas to make concurrent changes and later converge on the same logical state without relying on network arrival order or perfectly synchronized clocks.
import * as sequencer from '@sovereignbase/sequencer'
const sequence = sequencer.__create(/*optional stored snapshot*/)
const { reel, change } = sequencer.__update(sequence, 0, 'Hello World', 'after')
console.log(sequencer.__read(sequence, 0)) // "Hello World"
/// Summary and link to in detail benchmark readme
/// Auto inserted benchmark result and environment details.
JavaScript/WASM performance measured using Node.js 24.16.0 on Intel Core i5-10210U at 1.60 GHz. Diamond Types 1.0.2 is included under its upstream description, “The world's fastest CRDT. WIP.” Results use equivalent public operations where available; — means Diamond Types has no public equivalent. See the full benchmark report for methodology, API differences, and variability.
| function | Sequence length | Sequencer ops/sec | Diamond Types ops/sec | Sequencer calls | Diamond Types calls | Sequencer avg µs/op | Diamond Types avg µs/op |
|---|---|---|---|---|---|---|---|
__create |
100 | 53,359 | 31,036 | 256 | 256 | 18.741 | 32.221 |
__read |
100 | 10,493,179 | 213,995 | 131,072 | 256 | 0.09530 | 4.673 |
__length |
100 | 36,429,872 | 20,699,648 | 131,072 | 131,072 | 0.02745 | 0.04831 |
__recover |
100 | 392,927 | 222,668 | 256 | 256 | 2.545 | 4.491 |
__update |
100 | 163,532 | 309,406 | 256 | 256 | 6.115 | 3.232 |
__delete |
100 | 259,538 | 290,698 | 256 | 256 | 3.853 | 3.440 |
__merge |
100 | 116,904 | 56,117 | 256 | 256 | 8.554 | 17.820 |
__acknowledge |
100 | 6,729,475 | 1,395,089 | 4,096 | 4,096 | 0.1486 | 0.7168 |
compact |
100 | 270,856 | — | 256 | — | 3.692 | — |
__snapshot |
100 | 255,558 | 73,779 | 256 | 256 | 3.913 | 13.554 |
__create |
1,000 | 79,853 | 39,769 | 128 | 128 | 12.523 | 25.145 |
__read |
1,000 | 9,861,933 | 434,972 | 65,536 | 128 | 0.1014 | 2.299 |
__length |
1,000 | 19,988,007 | 26,567,481 | 65,536 | 65,536 | 0.05003 | 0.03764 |
__recover |
1,000 | 164,663 | 302,755 | 128 | 128 | 6.073 | 3.303 |
__update |
1,000 | 111,919 | 48,940 | 128 | 128 | 8.935 | 20.433 |
__delete |
1,000 | 302,663 | 93,853 | 128 | 128 | 3.304 | 10.655 |
__merge |
1,000 | 252,589 | 37,518 | 128 | 128 | 3.959 | 26.654 |
__acknowledge |
1,000 | 2,948,983 | 1,162,520 | 2,048 | 2,048 | 0.3391 | 0.8602 |
compact |
1,000 | 527,704 | — | 128 | — | 1.895 | — |
__snapshot |
1,000 | 156,715 | 54,864 | 128 | 128 | 6.381 | 18.227 |
__create |
10,000 | 2,573 | 17,225 | 64 | 64 | 388.702 | 58.055 |
__read |
10,000 | 5,020,080 | 103,040 | 32,768 | 64 | 0.1992 | 9.705 |
__length |
10,000 | 16,350,556 | 12,603,983 | 32,768 | 32,768 | 0.06116 | 0.07934 |
__recover |
10,000 | 16,344 | 106,826 | 64 | 64 | 61.183 | 9.361 |
__update |
10,000 | 38,438 | 7,982 | 64 | 64 | 26.016 | 125.289 |
__delete |
10,000 | 172,891 | 13,819 | 64 | 64 | 5.784 | 72.364 |
__merge |
10,000 | 46,100 | 10,454 | 64 | 64 | 21.692 | 95.656 |
__acknowledge |
10,000 | 3,225,806 | 968,054 | 1,024 | 1,024 | 0.3100 | 1.033 |
compact |
10,000 | 46,893 | — | 64 | — | 21.325 | — |
__snapshot |
10,000 | 43,301 | 22,213 | 64 | 64 | 23.094 | 45.019 |
__create |
100,000 | 142 | 1,438 | 16 | 16 | 7,056.825 | 695.625 |
__read |
100,000 | 4,083,299 | 10,018 | 8,192 | 16 | 0.2449 | 99.819 |
__length |
100,000 | 12,274,457 | 6,877,579 | 8,192 | 8,192 | 0.08147 | 0.1454 |
__recover |
100,000 | 878 | 17,337 | 16 | 16 | 1,138.744 | 57.681 |
__update |
100,000 | 98,580 | 1,812 | 16 | 16 | 10.144 | 551.969 |
__delete |
100,000 | 190,694 | 1,930 | 16 | 16 | 5.244 | 518.012 |
__merge |
100,000 | 89,485 | 1,372 | 16 | 16 | 11.175 | 728.825 |
__acknowledge |
100,000 | 4,182,350 | 1,050,089 | 256 | 256 | 0.2391 | 0.9523 |
compact |
100,000 | 320,616 | — | 16 | — | 3.119 | — |
__snapshot |
100,000 | 1,559 | 4,558 | 16 | 16 | 641.431 | 219.381 |
__create |
1,000,000 | 18 | 267 | 16 | 16 | 56,965.988 | 3,747.700 |
__read |
1,000,000 | 2,768,549 | 754 | 8,192 | 16 | 0.3612 | 1,327.000 |
__length |
1,000,000 | 22,381,379 | 8,496,177 | 8,192 | 8,192 | 0.04468 | 0.1177 |
__recover |
1,000,000 | 58 | 897 | 16 | 16 | 17,147.762 | 1,115.063 |
__update |
1,000,000 | 99,443 | 246 | 16 | 16 | 10.056 | 4,072.900 |
__delete |
1,000,000 | 108,401 | 269 | 16 | 16 | 9.225 | 3,723.856 |
__merge |
1,000,000 | 59,018 | 262 | 16 | 16 | 16.944 | 3,811.575 |
__acknowledge |
1,000,000 | 6,385,696 | 1,419,849 | 256 | 256 | 0.1566 | 0.7043 |
compact |
1,000,000 | 235,627 | — | 16 | — | 4.244 | — |
__snapshot |
1,000,000 | 156 | 912 | 16 | 16 | 6,398.656 | 1,096.031 |
|heap usage .... what ever is professional/smart
| format | raw | minified | minified + gzip |
|---|---|---|---|
| ESM | 91.3 kB | 53.8 kB | 19.0 kB |
| CommonJS | 91.6 kB | 56.3 kB | 19.3 kB |
Average delta size and average replica/snapshot size
| Delta workload | average bytes per operation | MessagePack | MessagePack + gzip | gzip reduction |
|---|---|---|---|---|
| 1,000 one-frame updates | 39.6 B | 39.6 kB | 7.8 kB | 80.2% |
| 1,000 one-frame masks | 36.0 B | 36.0 kB | 5.1 kB | 85.9% |
| Snapshot containing 1,000 one-frame strips | 39.6 B | 39.6 kB | 7.8 kB | 80.2% |
As an example, let's consider two editors, A and B, both working on the following text:
Hello world
The text has 11 characters and 12 possible insertion positions.
Both editors begin from the same state.
Editor A makes two changes:
H with Y.w after Hello.A now sees:
Yellow world
At roughly the same time, before receiving A's changes, editor B inserts ! at the end of the original text:
Hello world!
These changes are then exchanged over the network.
When A's changes arrive at B, B can produce the expected result:
Yellow world!
However, if B's operation is represented only as something like:
Insert "!" at position 11
then applying that operation to A's newer local state may produce:
Yellow worl!d
The operation was correct relative to the state in which it was created, but the numeric position no longer represents the same logical location after concurrent edits.
This is the fundamental problem: array indices and positions are not stable identities.
One possible solution is to introduce a central server that decides the order of operations.
However, this makes network arrival order part of the resulting state.
Depending on latency, the server may receive operations in a different order from the order in which users logically performed them. Two otherwise identical sets of operations could therefore produce different or unintuitive results depending on network conditions.
In other words:
network latency → operation order → resulting state
Another solution is to timestamp every operation.
However, wall clocks across different machines are never guaranteed to be perfectly synchronized. Clock skew can cause an operation created later to appear earlier, or an earlier operation to appear later.
/// short summary sequencer keeps footage in ts and communicates with native projector... + link to the in detail explanation of projector readme at src/c++/README.md
Sequencer gives a stable unique identifier to every frame in a sequence.
Instead of describing a change as:
Insert "!" at position 11
an operation can logically describe its relationship to existing sequence elements:
Insert <frame-id> after <frame-id> and resolve possible sibling order with a deterministic rule
The identity of that frame remains stable even when other frames are inserted or removed around it.
From any set of sequence frames, Sequencer can reconstruct a deterministic ordering.
This means replicas can:
Every npm test run rebuilds the native WebAssembly module and verifies unit
behaviour, deterministic convergence, generative "stress" scenarios, V8 coverage,
the supported runtime matrix, desktop browsers, mobile browser emulations, and
module Web Workers. Every stage has a hard timeout, and all detailed evidence is
written to the automated test report.
Runtimes with tested support:
Apache-2.0