* perf(project-tree): measure row widths once per frame
The horizontal scroll range was measured in a layout effect on every render:
each pass forced layout, its setState re-rendered synchronously and measured
again, and the ResizeObserver was recreated each time, firing once more.
Expanding a 10k-entry folder went from ~26 ms to ~63 ms.
Keep one observer per tree and coalesce renders and resizes into a single
measurement on the next animation frame. Expanding is back to ~30 ms and
arrow-key p50 drops from 3.3 ms to 1.7 ms; the widths behave as before.
* perf(github): load the pull requests integration after start-up
Actions, the tool window and the timeline editor stay registered at start-up;
their implementations, the connection and review-mode tracking load on idle
or on first use. Takes ~60 KB gzip off the initial bundle.
* perf(templates): load Emmet when an HTML or stylesheet editor opens
The Emmet engine (~70 KB minified) was part of the initial bundle; it now loads
with the first editor that can expand abbreviations, or with Update Tag with Emmet.
* perf(search, run): load popups and Edit Configurations when first shown
Search Everywhere, Find in Files, the recent files/locations popups, File
Structure and the Run/Debug Configurations dialog were part of the initial
bundle although each only renders while open. `lazyWhen` mounts a lazy view
only while its condition holds; the idle prefetch still loads them right after
start-up, so opening one stays as fast.
* perf: load dialogs, the SQL console and diff views on first use
- Database dialogs, Assign Shortcut and the Logcat tool window load when shown.
- The SQL console extensions load with the first SQL editor
(`lazyEditorExtension` reconfigures the editor once they arrive).
- The changes tree loads the diff viewer when a file is selected, and
"Open Repository Log" loads the revision browser when run.
* perf: load plugin, debugger and project popups when first shown
The IntelliJ theme import, the debugger's popovers and dialogs and the title
bar's project popup now load when first opened. `lazyWhen` keeps a view
mounted once shown, so its own open/closed handling is unchanged.
* perf(angular): parse only text with Angular syntax as Angular
Every text node of a template got its own nested Angular parse, including
the whitespace between tags, which is most of them. Text without a `{`, `}`
or `@` holds no interpolation or block, so it stays HTML text. A full parse
of a 12k-line template takes about a fifth less work.
* perf(angular): reuse nested trees of unchanged text and attributes
An edit makes the mixed parser recreate many text and attribute nodes it
does not keep: the document's own text and the nodes up to the viewport. It
reuses nested trees only of nodes it kept, so each of those was parsed again
as Angular on every keystroke (~170 nested parses per key in a 12k-line
template). Their parse depends only on their text, so the trees are now
remembered by text, up to about 2M characters.
Typing in the middle of a 12k-line template: main thread per key 57 -> 22 ms,
p50 latency 30 -> 19.5 ms, no long tasks.
* perf: budget typing in a large Angular template
* perf: measure code completion over a 2,000-item list
The harness's probe can answer completion with generated items through the
command route; language server requests go through a route when one is
installed, not only under Tauri. The scenario opens the popup by typing,
narrows it letter by letter and moves the selection, with budgets for each.
* perf(run): show a flood of console output at most every 50 ms
While a process printed thousands of lines a second, the Run console
appended, re-rendered and laid out on every frame, so typing in an editor
meanwhile missed the next frame 35% of the time. A line after a quiet spell
still shows on the next frame; a flood now updates the console at ~20 Hz,
and typing during it misses 2-5% (p50 16 -> 9.7 ms) with the output done as
fast as before.
The performance harness gets a scenario for it: 50,000 log lines at 200 a
frame (a dev and perf build action, run.sampleOutput) while typing.
* perf(vcs): keep Git Log rows from re-rendering on every selection change
Commit rows were memoized but received a new Set and new closures on every
render, so moving the selection re-rendered every visible row, and each row
built a new Intl.DateTimeFormat for its date. Rows now get stable handlers and
shared remote-name sets, and date formatting reuses cached formatters.
* perf: measure the Git Log and splitter dragging
gitLog shows 20k generated commits served page by page through a fake vcs_log,
walks the selection with the arrow keys and wheel-scrolls the list.
resizePanels drags the side and bottom splitters with an editor, the Project
tree and the Log open. The perf probe's fake backends can now be combined.
* perf: translate the sample output action and keep fake completion details out of the text catalog
* perf(vcs): keep Git Log scrolling smooth as pages load
Each page of the log recomputed hidden long edges by scanning every row once per
lane, and the store laid out the whole graph a second time for fields nothing
read. Long edges are now found in one pass over the rows, the unused store graph
is gone, and the next page is requested while a page of rows is still ahead so
fast scrolling doesn't reach the end before git answers. The commit list also
contains its layout, so rows entering while scrolling no longer relay out the
workbench.
* perf: load the Git Log scenario's pages with git's latency and scroll across several
The IDE you know, rebuilt in Rust.
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OpenIDEA brings the IntelliJ IDEA way of working — its keymap, its tool windows, its search-everything habits — to a native app with a Rust core.
Editor, code insight, debugger, Git, terminal, database and HTTP clients,
for 60+ languages. Builds for macOS, Windows and Linux. On Windows, if you'd
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Benchmark
Opening freqtrade (Python, ~770 files) with warm caches, median of 5 runs:
| OpenIDEA | IntelliJ IDEA 2026.2.3 | |
|---|---|---|
| Window with the project | 0.9 s | 3.1 s |
| Ready (CPU settled) | 1.1 s | 13.2 s |
| Memory (USS, all processes) | 169 MB | 2011 MB |
| CPU time until ready | 2.4 s | 47.9 s |
| Idle CPU | 4 % of a core | 7 % of a core |
| Quit | 0.3 s | 5.9 s |
A release build of OpenIDEA from main and IDEA with default settings and plugins, on
Windows 11, 32-core AMD, 62 GB RAM.
IDEA analyses Python more deeply, so "ready" doesn't mean the same work on
both sides. Both are measured from the outside, the same way: see
perf/compare to run it on your machine and projects.
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Install them from Settings › Plugins, or start your own with
openidea-plugin new — see Writing OpenIDEA plugins and
the official plugins. The plugin API is still a preview.
Community
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Discord — questions, feedback and release news.
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License
Apache 2.0. Bundled third-party assets are listed in THIRD_PARTY_LICENSES.md.
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Java language server choices and their capabilities are in docs/java.md.
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