What can Carto Desk do without an account?

The whole prescan. The style is parsed in your browser: layer and source integrity, paint versus layout placement, sprite and glyphs, zoom ranges, embedded Mapbox tokens, WCAG label contrast and layer hygiene. The prescan exports - the report, the layer inventory CSV, the contrast CSV, the palette JSON and the patched style.json - are all free, with no account and no run.

Can a guest run a review lane?

No. Running a lane is metered and this app does not sponsor guest runs, so a lane that is not a bundled replay needs a signed-in SkillSafe account. The one exception is a bundled example: a lane marked saved run - free replays a real saved model run at zero cost without signing in.

Which lanes replay free on the bundled examples?

The delivery ops style ships with a saved run for the Audit, Cartography and Render cost lanes. The air-quality style ships with a saved run for the Data layers lane. Those four combinations replay in full - findings, checks, palette, recipes and budget - without signing in. Every other combination is a paid run.

Does my style get uploaded?

Not until you run a lane. Everything is read in your browser: the prescan, the contrast table, the patcher and every export. When you do run a lane, the style is sent for that one review and nothing about it is stored anywhere except your own SkillSafe account history.

Can Carto Desk fix the style, not only report on it?

For the defects that are unambiguous, yes. The patcher moves a paint property found in layout and a layout property found in paint, deletes an embedded credential key, drops or renames a duplicate layer id, deletes switched-off layers and unused sources, and rewrites a linear stop function as an interpolate expression. It lists every change before you download, leaves every ambiguous case alone and says why, and it costs nothing.

How is label contrast measured without rendering the map?

From the declared colours. WCAG relative luminance and contrast ratio are computed for each text colour against the style's background layer, for each text colour against its own halo, and for each area fill against the background - including the stop colours inside expressions. The verdict is against 4.5:1 for normal text, 3:1 for large text and for non-text figure-ground. It compares the declared values, not a render.

What are the four lanes?

Audit asks whether the style parses, resolves and ships. Cartography asks whether a reader will find what they came for, judging hierarchy, palette and type. Data layers asks whether the data-driven layers encode the data honestly. Render cost asks what the style costs to draw - layer budget, symbols and the initialization waterfall.

Your Mapbox style, read closely before anyone else has to

Paste the style.json. Carto Desk parses it in your browser first — every layer's source resolved, every property checked against the block it belongs in, label contrast measured, embedded tokens found — and then a reviewer works through what is left.

Each example ships with one saved model run: the delivery style replays the Audit, Cartography and Render cost lanes, and the air-quality style replays Data layers. Those replay in full — findings, checks, palette, recipes and budget — without signing in and without spending a credit. A lane with a saved run for the style you have loaded is marked saved run — free in the lane bar above; every other lane needs an account, because this app does not sponsor guest runs.

Your Mapbox GL style JSON nothing pasted yet

Drag a style.json in, or Everything is read in your browser. Nothing uploads until you run.

Instant prescan — free, in your browser, no model

Free — no account, no run.

Who reads this map

What matters most this run

What this map is for — optional, and it changes the answer

Review

Lane

Style

Layers

Findings

Blocking

Checks

Check	Status	Note

Findings

Prescan reconciliation

Next steps

Take this further

Each button switches lanes, keeps your style, and carries this review's conclusions into the next one.

Raw model reply

The reply did not parse as the structured review, so here it is verbatim.

Your Mapbox style, read closely before anyone else has to

Instant prescan — free, in your browser, no model

Render budget — the perf lane's headline number, measured here for free

Patch this style — free, in your browser, no model

Reserving credits…

Review

Against your previous

Checks

Findings

Blocking before production

Palette

Expression recipes

Render budget

Wins, by impact

Prescan reconciliation

Next steps

Take this further

Raw model reply

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How this review was produced