diff --git a/lib/all-stations.js b/lib/all-stations.js
deleted file mode 100644
index 5bc9e1d..0000000
--- a/lib/all-stations.js
+++ /dev/null
@@ -1,27 +0,0 @@
-'use strict'
-
-let raw = require('db-stations/full.json')
-
-let data = {}
-for (let key in raw) {
-	if (!Object.prototype.hasOwnProperty.call(raw, key)) continue
-	const station = Object.assign({}, raw[key]) // clone
-
-	// todo: remove this remapping (breaking change!)
-	station.coordinates = station.location
-	delete station.location
-
-	data[station.id] = station
-}
-data = JSON.stringify(data) + '\n'
-raw = null
-
-const allStations = (req, res, next) => {
-	// res.sendFile(rawPath, {
-	// 	maxAge: 10 * 24 * 3600 * 1000 // 10 days
-	// }, next)
-	res.set('content-type', 'application/json')
-	res.send(data)
-}
-
-module.exports = allStations
diff --git a/lib/db-stations.js b/lib/db-stations.js
new file mode 100644
index 0000000..012f272
--- /dev/null
+++ b/lib/db-stations.js
@@ -0,0 +1,40 @@
+'use strict'
+
+const {statSync} = require('fs')
+const {full: readRawStations} = require('db-stations')
+
+// We don't have access to the publish date+time of the npm package,
+// so we use the ctime of db-stations/full.ndjson as an approximation.
+// todo: this is brittle, find a better way, e.g. a build script
+const timeModified = statSync(require.resolve('db-stations/full.ndjson')).ctime
+
+const pStations = new Promise((resolve, reject) => {
+	let raw = readRawStations()
+	raw.once('error', reject)
+
+	let data = Object.create(null)
+	raw.on('data', (station) => {
+		data[station.id] = station
+		if (Array.isArray(station.ril100Identifiers)) {
+			for (const ril100 of station.ril100Identifiers) {
+				data[ril100.rilIdentifier] = station
+			}
+		}
+		if (Array.isArray(station.additionalIds)) {
+			for (const addId of station.additionalIds) {
+				data[addId] = station
+			}
+		}
+	})
+	raw.once('end', () => {
+		raw = null
+		resolve({data, timeModified})
+	})
+})
+
+pStations.catch((err) => {
+	console.error(err)
+	process.exit(1) // todo: is this appropriate?
+})
+
+module.exports = pStations
diff --git a/lib/station.js b/lib/station.js
deleted file mode 100644
index 354fdc4..0000000
--- a/lib/station.js
+++ /dev/null
@@ -1,40 +0,0 @@
-'use strict'
-
-const stations = require('db-stations')
-
-const err400 = (msg) => {
-	const err = new Error(msg)
-	err.statusCode = 400
-	return err
-}
-
-// This is terribly inefficient, because we read all stations for every request.
-// todo: optimize it
-const route = (req, res, next) => {
-	const id = req.params.id.trim()
-	const stream = stations.full()
-
-	let found = false
-	const onStation = (station) => {
-		if (station.id !== id) return
-		found = true
-		stream.removeListener('data', onStation)
-
-		res.json(station)
-		next('/station/:id')
-	}
-	stream.on('data', onStation)
-
-	const onEnd = () => {
-		if (!found) return next(err400('Station not found.'))
-	}
-	stream.once('end', onEnd)
-
-	stream.once('error', (err) => {
-		stream.removeListener('data', onStation)
-		stream.removeListener('end', onEnd)
-		next(nerr)
-	})
-}
-
-module.exports = route
diff --git a/lib/stations.js b/lib/stations.js
deleted file mode 100644
index 2b885f9..0000000
--- a/lib/stations.js
+++ /dev/null
@@ -1,70 +0,0 @@
-'use strict'
-
-const autocomplete = require('db-stations-autocomplete')
-const allStations = require('db-stations/full.json')
-const parse = require('cli-native').to
-const createFilter = require('db-stations/create-filter')
-const ndjson = require('ndjson')
-
-const hasProp = (o, k) => Object.prototype.hasOwnProperty.call(o, k)
-
-const err400 = (msg) => {
-	const err = new Error(msg)
-	err.statusCode = 400
-	return err
-}
-
-const complete = (req, res, next) => {
-	const limit = req.query.results && parseInt(req.query.results) || 3
-	const fuzzy = parse(req.query.fuzzy) === true
-	const completion = parse(req.query.completion) !== false
-	const results = autocomplete(req.query.query, limit, fuzzy, completion)
-
-	const data = []
-	for (let result of results) {
-		// todo: make this more efficient
-		const station = allStations.find(s => s.id === result.id)
-		if (!station) continue
-
-		data.push(Object.assign(result, station))
-	}
-
-	res.json(data)
-	next()
-}
-
-const filter = (req, res, next) => {
-	if (Object.keys(req.query).length === 0) {
-		return next(err400('Missing properties.'))
-	}
-
-	const selector = Object.create(null)
-	for (let prop in req.query) {
-		const val = parse(req.query[prop])
-		// todo: derhuerst/db-rest#2
-		if (prop.slice(0, 12) === 'coordinates.') {
-			prop = prop.slice(12)
-		}
-		selector[prop] = val
-	}
-	const filter = createFilter(selector)
-
-	res.type('application/x-ndjson')
-	const out = ndjson.stringify()
-	out
-	.once('error', next)
-	.pipe(res)
-	.once('finish', () => next())
-
-	for (let station of allStations) {
-		if (filter(station)) out.write(station)
-	}
-	out.end()
-}
-
-const route = (req, res, next) => {
-	if (req.query.query) complete(req, res, next)
-	else filter(req, res, next)
-}
-
-module.exports = route
diff --git a/package.json b/package.json
index daff55e..5fae7ec 100644
--- a/package.json
+++ b/package.json
@@ -26,9 +26,10 @@
 		"db-hafas": "^3.0.1",
 		"db-stations": "^2.4.0",
 		"db-stations-autocomplete": "^2.1.0",
+		"etag": "^1.8.1",
 		"hafas-client-health-check": "^1.0.1",
 		"hafas-rest-api": "^1.2.1",
-		"ndjson": "^1.5.0"
+		"serve-buffer": "^2.0.0"
 	},
 	"scripts": {
 		"start": "node index.js"
diff --git a/routes/station.js b/routes/station.js
new file mode 100644
index 0000000..de4e12c
--- /dev/null
+++ b/routes/station.js
@@ -0,0 +1,28 @@
+'use strict'
+
+const pStations = require('../lib/db-stations')
+
+const err404 = (msg) => {
+	const err = new Error(msg)
+	err.statusCode = 404
+	return err
+}
+
+const stationRoute = (req, res, next) => {
+	const id = req.params.id.trim()
+
+	pStations
+	.then(({data, timeModified}) => {
+		const station = data[id]
+		if (!station) {
+			next(err404('Station not found.'))
+			return;
+		}
+
+		res.setHeader('Last-Modified', timeModified.toUTCString())
+		res.json(station)
+	})
+	.catch(next)
+}
+
+module.exports = stationRoute
diff --git a/routes/stations.js b/routes/stations.js
new file mode 100644
index 0000000..33cc3d9
--- /dev/null
+++ b/routes/stations.js
@@ -0,0 +1,112 @@
+'use strict'
+
+const computeEtag = require('etag')
+const serveBuffer = require('serve-buffer')
+const autocomplete = require('db-stations-autocomplete')
+const parse = require('cli-native').to
+const createFilter = require('db-stations/create-filter')
+let pAllStations = require('../lib/db-stations')
+
+const JSON_MIME = 'application/json'
+const NDJSON_MIME = 'application/x-ndjson'
+
+const toNdjsonBuf = (data) => {
+	const chunks = []
+	let i = 0, bytes = 0
+	for (const id in data) {
+		const sep = i++ === 0 ? '' : '\n'
+		const buf = Buffer.from(sep + JSON.stringify(data[id]), 'utf8')
+		chunks.push(buf)
+		bytes += buf.length
+	}
+	return Buffer.concat(chunks, bytes)
+}
+
+pAllStations = pAllStations.then(({data, timeModified}) => {
+	const asJson = Buffer.from(JSON.stringify(data), 'utf8')
+	const asNdjson = toNdjsonBuf(data)
+	return {
+		stations: data,
+		timeModified,
+		asJson: {data: asJson, etag: computeEtag(asJson)},
+		asNdjson: {data: asNdjson, etag: computeEtag(asNdjson)},
+	}
+})
+.catch((err) => {
+	console.error(err)
+	process.exit(1)
+})
+
+const err = (msg, statusCode = 500) => {
+	const err = new Error(msg)
+	err.statusCode = statusCode
+	return err
+}
+
+const complete = (req, res, next, q, allStations, onStation, onEnd) => {
+	const limit = q.results && parseInt(q.results) || 3
+	const fuzzy = parse(q.fuzzy) === true
+	const completion = parse(q.completion) !== false
+	const results = autocomplete(q.query, limit, fuzzy, completion)
+
+	const data = []
+	for (const result of results) {
+		const station = allStations[result.id]
+		if (!station) continue
+
+		Object.assign(result, station)
+		onStation(result)
+	}
+	onEnd()
+}
+
+const filter = (req, res, next, q, allStations, onStation, onEnd) => {
+	const selector = Object.create(null)
+	for (const prop in q) selector[prop] = parse(q[prop])
+	const filter = createFilter(selector)
+
+	for (const id in allStations) {
+		const station = allStations[id]
+		if (filter(station)) onStation(station)
+	}
+	onEnd()
+}
+
+const stationsRoute = (req, res, next) => {
+	const t = req.accepts([JSON_MIME, NDJSON_MIME])
+	if (t !== JSON_MIME && t !== NDJSON_MIME) {
+		return next(err(JSON + ' or ' + NDJSON_MIME, 406))
+	}
+
+	const head = t === JSON_MIME ? '{\n' : ''
+	const sep = t === JSON_MIME ? ',\n' : '\n'
+	const tail = t === JSON_MIME ? '\n}\n' : '\n'
+	let i = 0
+	const onStation = (s) => {
+		const j = JSON.stringify(s)
+		const field = t === JSON_MIME ? `"${s.id}":` : ''
+		res.write(`${i++ === 0 ? head : sep}${field}${j}`)
+	}
+	const onEnd = () => {
+		if (i > 0) res.end(tail)
+		else res.end(head + tail)
+	}
+
+	const q = req.query
+	pAllStations
+	.then(({stations, timeModified, asJson, asNdjson}) => {
+		res.setHeader('Last-Modified', timeModified.toUTCString())
+		if (Object.keys(req.query).length === 0) {
+			const data = t === JSON_MIME ? asJson.data : asNdjson.data
+			const etag = t === JSON_MIME ? asJson.etag : asNdjson.etag
+			serveBuffer(req, res, data, {timeModified, etag})
+		} else if (q.query) {
+			complete(req, res, next, q, stations, onStation, onEnd)
+		} else {
+			filter(req, res, next, q, stations, onStation, onEnd)
+		}
+	})
+	.catch(next)
+}
+
+module.exports = stationsRoute