diff --git a/src/data/openalex-domains.json.ts b/src/data/openalex-domains.json.ts
new file mode 100644
index 0000000..0f4f01a
--- /dev/null
+++ b/src/data/openalex-domains.json.ts
@@ -0,0 +1,35 @@
+import { HttpClient, Terminal } from '@effect/platform'
+import { NodeTerminal } from '@effect/platform-node'
+import { Schema } from '@effect/schema'
+import { Effect, Record } from 'effect'
+import { DomainIdFromUrlSchema, DomainIdSchema } from '../lib/OpenAlex.js'
+import { UrlFromStringSchema } from '../lib/Url.js'
+
+const Domains = Schema.Struct({
+  results: Schema.Array(
+    Schema.Struct({
+      id: Schema.compose(UrlFromStringSchema, DomainIdFromUrlSchema),
+      display_name: Schema.String,
+    }),
+  ),
+})
+
+const DomainNames = Schema.Record(DomainIdSchema, Schema.String)
+
+const program = Effect.gen(function* () {
+  const terminal = yield* Terminal.Terminal
+
+  const request = HttpClient.request.get('https://api.openalex.org/domains?per-page=200')
+
+  const data = yield* HttpClient.client
+    .fetchOk(request)
+    .pipe(Effect.andThen(HttpClient.response.schemaBodyJson(Domains)), Effect.scoped)
+
+  const transformedData = Record.fromIterableWith(data.results, domain => [domain.id, domain.display_name])
+
+  const encoded = yield* Schema.encode(Schema.parseJson(DomainNames))(transformedData)
+
+  yield* terminal.display(encoded)
+})
+
+await Effect.runPromise(program.pipe(Effect.provide(NodeTerminal.layer)))
diff --git a/src/requests.md b/src/requests.md
index 7ae8d58..34b85e9 100644
--- a/src/requests.md
+++ b/src/requests.md
@@ -15,6 +15,7 @@ const requests = FileAttachment('./data/requests.json')
   .json()
   .then(data => data.map(request => ({ ...request, timestamp: parseTimestamp(request.timestamp) })))
 
+const openAlexDomains = FileAttachment('./data/openalex-domains.json').json()
 const openAlexFields = FileAttachment('./data/openalex-fields.json').json()
 ```
 
@@ -23,6 +24,19 @@ const now = new Date()
 const firstRequest = d3.min(requests, request => request.timestamp)
 ```
 
+```js
+const chosenDomain = view(
+  Inputs.select([null, ...Object.keys(openAlexDomains)], {
+    label: 'Domain',
+    format: domain => (domain ? openAlexDomains[domain] : 'All domains'),
+  }),
+)
+```
+
+```js
+const requestsSelected = chosenDomain ? requests.filter(d => d.domains.includes(chosenDomain)) : requests
+```
+
 ```js
 const languageColor = Plot.scale({
   color: {
@@ -41,15 +55,16 @@ const languageColor = Plot.scale({
   },
 })
 
-const requestsByField = requests.flatMap(({ fields, ...request }) =>
-  fields.map(field => ({ ...request, field: openAlexFields[field].name })),
-)
+const requestsByField = requestsSelected
+  .flatMap(({ fields, ...request }) => fields.map(field => ({ ...request, field })))
+  .filter(request => (chosenDomain ? openAlexFields[request.field].domain === chosenDomain : true))
+  .map(({ field, ...request }) => ({ ...request, field: openAlexFields[field].name }))
 ```
 
 <div class="grid grid-cols-4">
   <div class="card">
     <h2>Requests</h2> 
-    <span class="big">${requests.length.toLocaleString("en-US")}</span>
+    <span class="big">${requestsSelected.length.toLocaleString("en-US")}</span>
   </div>
 </div>
 
@@ -68,7 +83,7 @@ function requestsByLanguageTimeline({ width } = {}) {
     x: { label: '', domain: [d3.utcSunday.floor(firstRequest), d3.utcSunday.ceil(now)] },
     marks: [
       Plot.rectY(
-        requests,
+        requestsSelected,
         Plot.binX(
           { y: 'count' },
           {