Browser compatibility and Baseline status for any web feature — offline, from bundled MDN data.
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Check whether web features are safe to ship: Baseline state and the date it crossed, the browser and version that limits support, whether the feature is deprecated or discouraged, and the share of tracked global traffic that requiring it would exclude. Evaluates up to 20 BCD keys or web-features ids per call; up to 100 may be sent, and entries past the 20th come back unevaluated in omitted_features for the next call.
Entries to check, each a browser-compat-data key such as css.selectors.has or a web-features id such as has, 1 to 200 characters. The first 20 are evaluated per call; up to 100 are accepted, and entries past the 20th are returned unevaluated in omitted_features. More than 100 entries, or an empty or longer entry anywhere in the list, is rejected against this schema; a whitespace-only entry anywhere returns invalid_feature_input. Call browsercompat_search_features first for any entry whose key you do not already know.
When true, an entry that is neither a key nor an id falls back to the search index, such as "Container queries (size)" or "Element.prototype.animate". Its best exact matches are accepted only when they name one feature: a single key resolves to that key, several keys of one web-features feature resolve to the feature with its feature-level Baseline and compat_keys, and matches spanning two features are a miss. Off by default so a typo returns a miss you can correct.
Check whether web features are safe to ship: Baseline state and the date it crossed, the browser and version that limits support, whether the feature is deprecated or discouraged, and the share of tracked global traffic that requiring it would exclude. Evaluates up to 20 BCD keys or web-features ids per call; up to 100 may be sent, and entries past the 20th come back unevaluated in omitted_features for the next call.
| Argument | Type | Description |
|---|---|---|
| resolve | boolean | When true, an entry that is neither a key nor an id falls back to the search index, such as "Container queries (size)" or "Element.prototype.animate". Its best exact matches are accepted only when they name one feature: a single key resolves to that key, several keys of one web-features feature resolve to the feature with its feature-level Baseline and compat_keys, and matches spanning two features are a miss. Off by default so a typo returns a miss you can correct. |
| features* | array | Entries to check, each a browser-compat-data key such as css.selectors.has or a web-features id such as has, 1 to 200 characters. The first 20 are evaluated per call; up to 100 are accepted, and entries past the 20th are returned unevaluated in omitted_features. More than 100 entries, or an empty or longer entry anywhere in the list, is rejected against this schema; a whitespace-only entry anywhere returns invalid_feature_input. Call browsercompat_search_features first for any entry whose key you do not already know. |
{
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"features"
],
"properties": {
"resolve": {
"type": "boolean",
"default": false,
"description": "When true, an entry that is neither a key nor an id falls back to the search index, such as \"Container queries (size)\" or \"Element.prototype.animate\". Its best exact matches are accepted only when they name one feature: a single key resolves to that key, several keys of one web-features feature resolve to the feature with its feature-level Baseline and compat_keys, and matches spanning two features are a miss. Off by default so a typo returns a miss you can correct."
},
"features": {
"type": "array",
"items": {
"type": "string",
"maxLength": 200,
"minLength": 1
},
"maxItems": 100,
"minItems": 1,
"description": "Entries to check, each a browser-compat-data key such as css.selectors.has or a web-features id such as has, 1 to 200 characters. The first 20 are evaluated per call; up to 100 are accepted, and entries past the 20th are returned unevaluated in omitted_features. More than 100 entries, or an empty or longer entry anywhere in the list, is rejected against this schema; a whitespace-only entry anywhere returns invalid_feature_input. Call browsercompat_search_features first for any entry whose key you do not already know."
}
},
"additionalProperties": false
}Compute whether a set of web features clears an explicit browserslist target query. Compares up to 20 features per call; up to 100 may be sent, and entries past the 20th come back unevaluated in omitted_features for the next call. Every call evaluates the whole query: each feature gets a verdict, the count of failing targets, those targets grouped into runs of consecutive query targets per browser in failing_ranges, and its own evaluated and unevaluated target counts with the share of tracked traffic each covers. The target rows behind those numbers — which release each target maps to, which targets were not evaluated and why, and the failing and unevaluated targets of each feature, a failing row carrying the prefix, alternative name, or flag behind its verdict — cover at most ten query targets per call; page through them with target_offset and target_limit, and the verdicts, coverage, and totals stay identical on every page. A target counts as evaluated only where compatibility data was read for it, so a feature clears only when every target in the query was evaluated and supports it, and is inconclusive otherwise — a query that includes a browser with no compatibility data, as "defaults" does, never clears. A BCD key is judged on its own per-browser support. A web-features id spanning several keys, such as grid, is judged on the release web-features lists for the feature as a whole in each Baseline core browser, as support_source says; its other browsers are not evaluated.
| Argument | Type | Description |
|---|---|---|
| resolve | boolean | When true, an entry that is neither a key nor an id falls back to the search index, such as "Container queries (size)" or "Element.prototype.animate". Its best exact matches are accepted only when they name one feature: a single key resolves to that key and is judged on it, several keys of one web-features feature resolve to the feature and are judged on its feature-level support with compat_keys, and matches spanning two features are a miss. Off by default so a typo returns a miss you can correct rather than a confident answer about the wrong feature. |
Get the compatibility record for one web feature: Baseline state and the date it crossed, deprecation and standards status, per-browser version added and removed with flags, vendor prefixes and partial-implementation notes — with every other support statement recorded for that browser, such as an earlier prefixed or flagged release, in other_statements — and the MDN and specification links. Accepts a BCD key such as css.selectors.has or a web-features id such as has; the response echoes which one it matched. A web-features id that spans several BCD keys, such as grid, returns web-features’ own feature-level release per Baseline core browser in feature_support and its compat_keys, 100 per page, in place of per-key fields. An unresolved feature returns found: false with guidance rather than an error.
| Argument | Type | Description |
|---|---|---|
| feature* | string | A browser-compat-data key such as css.selectors.has, or a web-features id such as has, 1 to 200 characters. An empty or longer string is rejected against this schema; a whitespace-only string returns invalid_feature_input. Call browsercompat_search_features first if you do not already know the key. |
| resolve | boolean | When true, a string that is neither a key nor an id falls back to the search index, such as "Container queries (size)" or "Element.prototype.animate". Its best exact matches are accepted only when they name one feature: a single key resolves to that key, several keys of one web-features feature resolve to the feature with its feature_support and compat_keys, and matches spanning two features are a miss. Off by default so a typo returns a miss you can correct rather than a confident answer about the wrong feature. |
| subkeys_offset | integer |
Enumerate the reference vocabulary this server uses: BCD namespaces, BCD browser ids, browserslist agent ids and their BCD counterparts, Baseline states, web-features groups, and ECMAScript snapshots. Use it to build valid inputs for the other tools and to see which target browsers can be evaluated.
| Argument | Type | Description |
|---|---|---|
| topic* | string | Which vocabulary to list: bcd_namespaces for the 12 top-level browser-compat-data namespaces, bcd_browsers for the 17 tracked browsers, browserslist_agents for the 19 browserslist ids mapped to browser-compat-data browsers, baseline_states for the 4 Baseline states, groups for the 104 web-features groups, or snapshots for the 11 ECMAScript snapshots. |
{
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"topic"
],
"properties": {
"topic": {
"enum": [
"bcd_namespaces",
"bcd_browsers",
"browserslist_agents",
"baseline_states",
"groups",
"snapshots"
],
"type": "string",
"description": "Which vocabulary to list: bcd_namespaces for the 12 top-level browser-compat-data namespaces, bcd_browsers for the 17 tracked browsers, browserslist_agents for the 19 browserslist ids mapped to browser-compat-data browsers, baseline_states for the 4 Baseline states, groups for the 104 web-features groups, or snapshots for the 11 ECMAScript snapshots."
}
},
"additionalProperties": false
}Find web features by plain name or keyword when the canonical key is unknown, across CSS, JavaScript, HTML, Web APIs, SVG, MathML, WebAssembly, and HTTP headers. Returns ranked matches with the BCD key, the web-features id, the Baseline state, a one-line support summary, and which field matched. Feed a result key into browsercompat_get_feature for the full record.
| Argument | Type | Description |
|---|---|---|
| group | string | Restrict results to features in one web-features group or any group nested under it, for example "selectors" or "css". Keys with no web-features mapping never match. Call browsercompat_list_reference with topic groups for valid ids. |
| limit | integer | Maximum results to return, at most 50 per call; a value from 51 to 1000 is served as 50. When matches remain, cap reports the size applied and nextOffset continues. |
| query* | string | Plain-language name, keyword, or code notation, for example "container query", "fromAsync", "Array.prototype.at", "display: grid", or "<dialog>". |
| offset | integer | Number of ranked matches to skip before returning results, for paging past limit. Pass the nextOffset from the previous response. |
| baseline | string | Restrict results to one Baseline state. |
| snapshot | string |
| targets* | string | A browserslist query, for example "defaults" or "> 0.5%, last 2 versions", 1 to 500 characters. Required: with no query browserslist would read config from the process working directory rather than from your project. |
| features* | array | Entries to compare, each a browser-compat-data key such as css.selectors.has or a web-features id such as has, 1 to 200 characters. The first 20 are compared per call; up to 100 are accepted, and entries past the 20th are returned unevaluated in omitted_features. More than 100 entries, or an empty or longer entry anywhere in the list, is rejected against this schema; a whitespace-only entry anywhere returns invalid_feature_input. Call browsercompat_search_features first for any entry whose key you do not already know. |
| target_limit | integer | How many query targets this page covers, at most 10 per call; a value from 11 to 1000 is served as 10, and the cap enrichment field reports the size applied. It bounds every list of target rows in the response and never the evaluation: verdicts, coverage, and totals always describe the whole query. |
| target_offset | integer | Zero-based position in the target list of the query at which this page of target rows starts. Pass the nextOffset of the previous response to continue. An offset at or past the number of targets returns the whole-query verdicts and totals with no target rows. |
{
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"features",
"targets"
],
"properties": {
"resolve": {
"type": "boolean",
"default": false,
"description": "When true, an entry that is neither a key nor an id falls back to the search index, such as \"Container queries (size)\" or \"Element.prototype.animate\". Its best exact matches are accepted only when they name one feature: a single key resolves to that key and is judged on it, several keys of one web-features feature resolve to the feature and are judged on its feature-level support with compat_keys, and matches spanning two features are a miss. Off by default so a typo returns a miss you can correct rather than a confident answer about the wrong feature."
},
"targets": {
"type": "string",
"maxLength": 500,
"minLength": 1,
"description": "A browserslist query, for example \"defaults\" or \"> 0.5%, last 2 versions\", 1 to 500 characters. Required: with no query browserslist would read config from the process working directory rather than from your project."
},
"features": {
"type": "array",
"items": {
"type": "string",
"maxLength": 200,
"minLength": 1
},
"maxItems": 100,
"minItems": 1,
"description": "Entries to compare, each a browser-compat-data key such as css.selectors.has or a web-features id such as has, 1 to 200 characters. The first 20 are compared per call; up to 100 are accepted, and entries past the 20th are returned unevaluated in omitted_features. More than 100 entries, or an empty or longer entry anywhere in the list, is rejected against this schema; a whitespace-only entry anywhere returns invalid_feature_input. Call browsercompat_search_features first for any entry whose key you do not already know."
},
"target_limit": {
"type": "integer",
"default": 10,
"maximum": 1000,
"minimum": 1,
"description": "How many query targets this page covers, at most 10 per call; a value from 11 to 1000 is served as 10, and the cap enrichment field reports the size applied. It bounds every list of target rows in the response and never the evaluation: verdicts, coverage, and totals always describe the whole query."
},
"target_offset": {
"type": "integer",
"default": 0,
"maximum": 9007199254740991,
"minimum": 0,
"description": "Zero-based position in the target list of the query at which this page of target rows starts. Pass the nextOffset of the previous response to continue. An offset at or past the number of targets returns the whole-query verdicts and totals with no target rows."
}
},
"additionalProperties": false
}| Direct child keys to skip, default 0. Each subkeys page contains at most 100 keys; pass its next_offset to continue. |
| include_runtimes | boolean | Add the bun, deno, nodejs, and oculus rows to support. Leave off for browser ship decisions. |
| compat_keys_offset | integer | compat_keys to skip, default 0, for a web-features id that spans several keys. Each page of compat_keys holds at most 100; pass compat_keys_next_offset to continue. Has no effect when the feature resolves to a single key. |
{
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"feature"
],
"properties": {
"feature": {
"type": "string",
"maxLength": 200,
"minLength": 1,
"description": "A browser-compat-data key such as css.selectors.has, or a web-features id such as has, 1 to 200 characters. An empty or longer string is rejected against this schema; a whitespace-only string returns invalid_feature_input. Call browsercompat_search_features first if you do not already know the key."
},
"resolve": {
"type": "boolean",
"default": false,
"description": "When true, a string that is neither a key nor an id falls back to the search index, such as \"Container queries (size)\" or \"Element.prototype.animate\". Its best exact matches are accepted only when they name one feature: a single key resolves to that key, several keys of one web-features feature resolve to the feature with its feature_support and compat_keys, and matches spanning two features are a miss. Off by default so a typo returns a miss you can correct rather than a confident answer about the wrong feature."
},
"subkeys_offset": {
"type": "integer",
"default": 0,
"maximum": 9007199254740991,
"minimum": 0,
"description": "Direct child keys to skip, default 0. Each subkeys page contains at most 100 keys; pass its next_offset to continue."
},
"include_runtimes": {
"type": "boolean",
"default": false,
"description": "Add the bun, deno, nodejs, and oculus rows to support. Leave off for browser ship decisions."
},
"compat_keys_offset": {
"type": "integer",
"default": 0,
"maximum": 9007199254740991,
"minimum": 0,
"description": "compat_keys to skip, default 0, for a web-features id that spans several keys. Each page of compat_keys holds at most 100; pass compat_keys_next_offset to continue. Has no effect when the feature resolves to a single key."
}
},
"additionalProperties": false
}| Restrict results to features in one ECMAScript snapshot, for example "ecmascript-2023". Call browsercompat_list_reference with topic snapshots for valid ids. |
| namespace | string | Restrict results to one top-level browser-compat-data namespace. |
{
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"query"
],
"properties": {
"group": {
"type": "string",
"maxLength": 100,
"minLength": 1,
"description": "Restrict results to features in one web-features group or any group nested under it, for example \"selectors\" or \"css\". Keys with no web-features mapping never match. Call browsercompat_list_reference with topic groups for valid ids."
},
"limit": {
"type": "integer",
"default": 10,
"maximum": 1000,
"minimum": 1,
"description": "Maximum results to return, at most 50 per call; a value from 51 to 1000 is served as 50. When matches remain, cap reports the size applied and nextOffset continues."
},
"query": {
"type": "string",
"maxLength": 100,
"minLength": 1,
"description": "Plain-language name, keyword, or code notation, for example \"container query\", \"fromAsync\", \"Array.prototype.at\", \"display: grid\", or \"<dialog>\"."
},
"offset": {
"type": "integer",
"default": 0,
"maximum": 9007199254740991,
"minimum": 0,
"description": "Number of ranked matches to skip before returning results, for paging past limit. Pass the nextOffset from the previous response."
},
"baseline": {
"enum": [
"widely",
"newly",
"limited",
"not_mapped"
],
"type": "string",
"description": "Restrict results to one Baseline state."
},
"snapshot": {
"type": "string",
"maxLength": 100,
"minLength": 1,
"description": "Restrict results to features in one ECMAScript snapshot, for example \"ecmascript-2023\". Call browsercompat_list_reference with topic snapshots for valid ids."
},
"namespace": {
"enum": [
"api",
"css",
"html",
"http",
"javascript",
"manifests",
"mathml",
"mediatypes",
"svg",
"webassembly",
"webdriver",
"webextensions"
],
"type": "string",
"description": "Restrict results to one top-level browser-compat-data namespace."
}
},
"additionalProperties": false
}