diff --git a/REBUILD.md b/REBUILD.md
index 8211339..5e8d563 100644
--- a/REBUILD.md
+++ b/REBUILD.md
@@ -41,8 +41,11 @@ dropping garbage; 28 TB of compressed overview traffic. Throughput goal:
    Order: oldest era first (2008–2018 holds 63% of the readable files on
    17% of the lines), then forward.
 
-2. **Edge worker** (node, TypeScript reusing `lib/`; Rust later only if
-   CPU-bound). Per lease: compressed chunks of 10–50 k lines, in order →
+2. **Edge worker** (node, TypeScript reusing `lib/`). Measured (`edge:bench`,
+   2026-10-09): 73 k headers/s per core on an a.b.ath range from 2013,
+   103 k/s on a recent a.b.boneless range (2 M headers each), ~1.2 GB peak
+   per process; the 25 B lines/day goal needs ~3–4 cores over all nodes,
+   so no Rust. Per lease: compressed chunks of 10–50 k lines, in order →
    parse subjects → skip crossposts outside their owner group (of the
    indexed groups in the article's Xref, the one with the lowest priority
    number; see the group list) → group articles into files → files
diff --git a/commands/edge_bench.ts b/commands/edge_bench.ts
new file mode 100644
index 0000000..72b76dc
--- /dev/null
+++ b/commands/edge_bench.ts
@@ -0,0 +1,130 @@
+import { BaseCommand, flags } from '@adonisjs/core/ace'
+import type { CommandOptions } from '@adonisjs/core/types/ace'
+import { mkdir, readFile, readdir, writeFile } from 'node:fs/promises'
+import { join } from 'node:path'
+import { unzipSync } from 'node:zlib'
+import env from '#start/env'
+import { XoverClient, parseOverviews } from '#lib/nntp/index'
+import { RangeIndexer } from '#lib/edge/index'
+import { DEFAULT_RULES, type Rules } from '#lib/rules/index'
+
+/**
+ * Measures the edge worker on a real range (REBUILD.md: TypeScript or Rust):
+ * --capture saves a range's compressed XOVER chunks to a directory once;
+ * without it the saved chunks are replayed through the range indexer, timing
+ * inflate, parse and indexing per chunk, with memory and output sizes.
+ */
+export default class EdgeBench extends BaseCommand {
+  static commandName = 'edge:bench'
+  static description = 'Measures the edge worker on a captured range'
+  static options: CommandOptions = { startApp: true }
+
+  @flags.string({ description: 'Directory of the captured chunks', required: true })
+  declare dir: string
+
+  @flags.boolean({ description: 'Capture the range first (needs NNTP_* in the environment)' })
+  declare capture: boolean
+
+  @flags.string({ description: 'Group to capture' })
+  declare group?: string
+
+  @flags.number({ description: 'First article to capture' })
+  declare start?: number
+
+  @flags.number({ description: 'Articles to capture', default: 2_000_000 })
+  declare articles: number
+
+  @flags.number({ description: 'Articles per XOVER', default: 50_000 })
+  declare chunk: number
+
+  @flags.number({ description: 'Chunks without a new part before an open file is given up', default: 5 })
+  declare idle: number
+
+  @flags.string({ description: 'Indexed groups in priority order, comma-separated (owner rule)' })
+  declare priorities?: string
+
+  async run() {
+    if (this.capture) await this.captureRange()
+    await this.replay()
+  }
+
+  private async captureRange() {
+    if (!this.group || this.start === undefined) throw new Error('--group and --start are needed to capture')
+    await mkdir(this.dir, { recursive: true })
+    const client = await XoverClient.connect({
+      host: env.get('NNTP_HOST')!,
+      port: env.get('NNTP_PORT')!,
+      user: env.get('NNTP_USER'),
+      password: env.get('NNTP_PASSWORD'),
+      secure: env.get('NNTP_SECURE', true),
+      compress: true,
+      timeoutMs: 300_000,
+    })
+    await client.group(this.group)
+    const end = this.start + this.articles - 1
+    let index = 0
+    for (let from = this.start; from <= end; from += this.chunk, index++) {
+      const to = Math.min(from + this.chunk - 1, end)
+      const started = Date.now()
+      const raw = await client.xoverRaw(from, to)
+      await writeFile(join(this.dir, `${String(index).padStart(4, '0')}-${from}-${to}.gz`), raw)
+      this.logger.info(`chunk ${index}: ${from}–${to}, ${(raw.length / 1e6).toFixed(1)} MB in ${((Date.now() - started) / 1000).toFixed(1)} s`)
+    }
+    await writeFile(join(this.dir, 'range.json'), JSON.stringify({ group: this.group, start: this.start, end }))
+    client.close()
+  }
+
+  private async replay() {
+    const { group, start, end } = JSON.parse(await readFile(join(this.dir, 'range.json'), 'utf8')) as { group: string; start: number; end: number }
+    const priorities = Object.fromEntries((this.priorities ?? group).split(',').map((g, i) => [g.trim(), i + 1]))
+    if (!(group in priorities)) priorities[group] = Object.keys(priorities).length + 1
+    const rules: Rules = { ...DEFAULT_RULES, priorities, droppedSignatures: [] }
+    const files = (await readdir(this.dir)).filter((f) => f.endsWith('.gz')).sort()
+    const indexer = new RangeIndexer({ group, start, end, rules, idleChunks: this.idle })
+    const t = { inflate: 0, parse: 0, index: 0 }
+    let compressed = 0
+    let text = 0
+    let peakRss = 0
+    const out = { headers: 0, releases: 0, files: 0, segments: 0, payload: 0, candidates: 0, fragments: 0, samples: 0 }
+    const counts = new Map<string, number>()
+    const cpuStart = process.cpuUsage()
+    const wall = Date.now()
+    for (const file of files) {
+      const raw = await readFile(join(this.dir, file))
+      compressed += raw.length
+      let at = performance.now()
+      const data = unzipSync(raw).toString('utf8')
+      t.inflate += performance.now() - at
+      text += data.length
+      at = performance.now()
+      const overviews = parseOverviews(data)
+      t.parse += performance.now() - at
+      at = performance.now()
+      const next = Number(file.split('-')[2].replace('.gz', '')) + 1
+      indexer.add(overviews, next)
+      if (file === files.at(-1)) indexer.finish()
+      const batch = indexer.take()
+      t.index += performance.now() - at
+      out.headers += batch.headers
+      out.releases += batch.releases.length
+      for (const r of batch.releases) {
+        out.files += r.files
+        out.segments += r.segments
+        out.payload += r.payload.length
+      }
+      out.candidates += batch.candidates.length
+      out.fragments += batch.fragments.length
+      out.samples += batch.samples.length
+      for (const c of batch.counts) counts.set(`${c.rule} ${c.key}`.trim(), (counts.get(`${c.rule} ${c.key}`.trim()) ?? 0) + c.articles)
+      peakRss = Math.max(peakRss, process.memoryUsage().rss)
+    }
+    const cpu = process.cpuUsage(cpuStart)
+    const cpuS = (cpu.user + cpu.system) / 1e6
+    const total = t.inflate + t.parse + t.index
+    this.logger.info(`${group} ${start}–${end}: ${files.length} chunks, ${(compressed / 1e6).toFixed(0)} MB compressed, ${(text / 1e6).toFixed(0)} MB text`)
+    this.logger.info(`${out.headers.toLocaleString('en')} headers in ${(total / 1000).toFixed(1)} s (${Math.round(out.headers / (total / 1000)).toLocaleString('en')}/s on one core; CPU ${cpuS.toFixed(1)} s, wall ${((Date.now() - wall) / 1000).toFixed(1)} s)`)
+    this.logger.info(`  inflate ${(t.inflate / 1000).toFixed(1)} s, parse ${(t.parse / 1000).toFixed(1)} s, index ${(t.index / 1000).toFixed(1)} s; peak RSS ${(peakRss / 1e6).toFixed(0)} MB`)
+    this.logger.info(`  kept: ${out.releases} release chunks, ${out.files} files, ${out.segments} segments, payload ${(out.payload / 1e6).toFixed(1)} MB (${(out.payload / Math.max(1, out.segments)).toFixed(1)} B/segment); ${out.candidates} candidates, ${out.fragments} fragments, ${out.samples} samples`)
+    for (const [k, v] of [...counts].sort((a, b) => b[1] - a[1]).slice(0, 8)) this.logger.info(`  dropped ${k}: ${v.toLocaleString('en')} articles`)
+  }
+}
diff --git a/start/env.ts b/start/env.ts
index b1f15a7..358c134 100644
--- a/start/env.ts
+++ b/start/env.ts
@@ -34,4 +34,11 @@ export default await Env.create(new URL('../', import.meta.url), {
   DB_POOL_MAX: Env.schema.number.optional(),
   DB_SEARCH_PATH: Env.schema.string.optional(),
   DB_DEBUG: Env.schema.boolean.optional(),
+
+  // NNTP (the coordinator's relay; edge:bench --capture)
+  NNTP_HOST: Env.schema.string.optional(),
+  NNTP_PORT: Env.schema.number.optional(),
+  NNTP_USER: Env.schema.string.optional(),
+  NNTP_PASSWORD: Env.schema.string.optional(),
+  NNTP_SECURE: Env.schema.boolean.optional(),
 })