diff --git a/apps/match/src/match.app.ts b/apps/match/src/match.app.ts
index 0aa6c15..c55f146 100644
--- a/apps/match/src/match.app.ts
+++ b/apps/match/src/match.app.ts
@@ -229,6 +229,40 @@ function tachyonServerFor(env: Env, roomInstanceId: number): TachyonServer {
 	return pool[roomInstanceId % pool.length] ?? NO_TACHYON_SERVER
 }
 
+/**
+ * The Tachyon port a DEVELOPER is handed, in place of the port on the pool entry their
+ * instance resolved to. Developers connect to a separate Tachyon build running beside the
+ * live one on the same box, so only the PORT moves: the HOST stays whichever one
+ * {@link tachyonServerFor} picked, rather than scattering developers off the pool.
+ */
+const DEVELOPER_TACHYON_PORT = '7778'
+
+/**
+ * The id displayed for that dev server. Not `tachyon-N` — the generated ids are positional
+ * names for entries in the pool ({@link tachyonPool}), and the dev build is not one of
+ * them: it is a different server that happens to share a host. The id is cosmetic (the
+ * client displays it and never sends it anywhere), so it only has to say which server the
+ * player is on, and "dev" is that.
+ */
+const DEVELOPER_TACHYON_SERVER_ID = 'dev'
+
+/**
+ * `server` with its port replaced by {@link DEVELOPER_TACHYON_PORT} and its id by
+ * {@link DEVELOPER_TACHYON_SERVER_ID}. An empty address is left alone — the pool is unset or
+ * the caller is in no instance, so there is no server to point at another port, and writing
+ * a bare `:7778` would hand the client an address that answers nothing (and name a server
+ * that isn't there). Splits on the LAST colon so a bracketed IPv6 host survives.
+ */
+function developerTachyonServer(server: TachyonServer): TachyonServer {
+	if (server.hostPort === '') return server
+	const colon = server.hostPort.lastIndexOf(':')
+	const host = colon === -1 ? server.hostPort : server.hostPort.slice(0, colon)
+	return {
+		hostPort: `${host}:${DEVELOPER_TACHYON_PORT}`,
+		serverId: DEVELOPER_TACHYON_SERVER_ID,
+	}
+}
+
 /**
  * Networking feature flags the client reads off its connection info. Verbatim from
  * the reference server — the client changes how it replicates based on these, so they
@@ -2872,7 +2906,9 @@ const app = new Hono<App>()
 				'fields name the Tachyon server that instance was assigned — one entry out of the',
 				'`TACHYON_HOST_PORT` pool, chosen by instance id so every player in a session is',
 				'handed the same one, with a generated `voiceServerId` (`tachyon-1`, `tachyon-2`,',
-				'…). Both are empty when the pool is unset or the caller is in no instance.',
+				'…). Both are empty when the pool is unset or the caller is in no instance. A',
+				'caller holding the DEVELOPER role gets that same host on port 7778, the dev',
+				'Tachyon build, with a `voiceServerId` of `dev`.',
 				'`experiments` carries the client’s networking flags.',
 			].join(' '),
 			security: AUTHED,
@@ -2911,8 +2947,13 @@ const app = new Hono<App>()
 					photonRoomId = instance?.photonRoomId ?? ''
 				}
 			}
-			// The instance's server, the same one every other player in it is handed.
-			const tachyon = tachyonServerFor(c.env, roomInstanceId)
+			const account = await getAccount(c.env.DB, id)
+			// The instance's server, the same one every other player in it is handed — except
+			// for a DEVELOPER, who is sent to the same host on the dev port, under the id
+			// `dev` rather than the pool entry's positional name.
+			const assigned = tachyonServerFor(c.env, roomInstanceId)
+			const tachyon =
+				account?.isDeveloper === true ? developerTachyonServer(assigned) : assigned
 
 			// Identifies the player to Photon. Signed with the shared JWT secret; the token's
 			// `aud` is the realtime app it's for. Nothing verifies it while Photon is
@@ -2920,7 +2961,7 @@ const app = new Hono<App>()
 			const photonAuthToken = await generatePhotonAuthToken(
 				id,
 				{
-					platformId: (await getAccount(c.env.DB, id))?.platformId ?? '',
+					platformId: account?.platformId ?? '',
 					platform: presence?.platform ?? 0,
 					deviceClass: presence?.deviceClass ?? 0,
 					audience: apps.photonRealtimeAppId,
@@ -2936,7 +2977,8 @@ const app = new Hono<App>()
 					photonRoomId,
 					// The Tachyon server this instance runs on, picked out of the operator's
 					// pool by {@link tachyonServerFor} — empty strings when the pool is empty
-					// or the caller is in no instance. Empty rather than null: the client's
+					// or the caller is in no instance, and on the dev port (id `dev`) for a
+					// developer. Empty rather than null: the client's
 					// decoder is likelier to accept a missing-value string than a null on a
 					// string field. The presence payload's NULL_CONNECTION_INFO keeps its
 					// nulls — that one never carries credentials.
diff --git a/apps/match/src/openapi.ts b/apps/match/src/openapi.ts
index c79407d..b10086e 100644
--- a/apps/match/src/openapi.ts
+++ b/apps/match/src/openapi.ts
@@ -216,8 +216,9 @@ export const ConnectionExperiments = z.object({
  * and `photonRoomId`, the Photon room of the instance their presence says they're in
  * — the same name every other player in that instance is handed. The voice fields name
  * the Tachyon server that instance was assigned out of the `TACHYON_HOST_PORT` pool —
- * likewise the same for everyone in the session — and are empty when the pool is unset
- * or the caller is in no instance. `photonRegion` matches the one stamped
+ * likewise the same for everyone in the session, except that a caller holding the
+ * DEVELOPER role is sent to that host's port 7778 as `dev` — and are empty when the pool
+ * is unset or the caller is in no instance. `photonRegion` matches the one stamped
  * on every room instance, so the two can't disagree.
  */
 export const ConnectionInfo = z.object({
@@ -229,10 +230,14 @@ export const ConnectionInfo = z.object({
 	photonRoomId: z.string().describe('The caller’s current instance; empty when they’re in none'),
 	voiceConnectionInfo: z
 		.string()
-		.describe('The instance’s Tachyon server, `host:port`; empty when none is configured'),
+		.describe(
+			'The instance’s Tachyon server, `host:port` (port 7778 for a developer); empty when none is configured'
+		),
 	voiceServerId: z
 		.string()
-		.describe('That server’s generated id (`tachyon-1`, …); cosmetic, empty when there is none'),
+		.describe(
+			'That server’s generated id (`tachyon-1`, …; `dev` for a developer); cosmetic, empty when there is none'
+		),
 	experiments: ConnectionExperiments,
 })
 
diff --git a/apps/match/src/test/integration/api.test.ts b/apps/match/src/test/integration/api.test.ts
index 091d567..1f969e4 100644
--- a/apps/match/src/test/integration/api.test.ts
+++ b/apps/match/src/test/integration/api.test.ts
@@ -1491,6 +1491,64 @@ describe('auth-gated endpoints', () => {
 		}
 	})
 
+	test('a developer is sent to the same Tachyon host on the dev port', async () => {
+		// Developers run against a Tachyon build listening on 7778 beside the live one, so
+		// only the host carries over from the instance's assignment — the dev build is not an
+		// entry in the pool, so it is named `dev` rather than borrowing that entry's
+		// positional `tachyon-N`.
+		await env.DB.prepare('INSERT OR IGNORE INTO account (data) VALUES (?1)')
+			.bind(JSON.stringify({ accountId: 974, username: 'Devver', isDeveloper: true }))
+			.run()
+		const original = env.TACHYON_HOST_PORT
+		try {
+			// One entry, so the assignment can't happen to land on 7778 by itself.
+			env.TACHYON_HOST_PORT = '198.51.100.12:7777'
+
+			const voiceFor = async (player: string, roomInstanceId: number) => {
+				const res = await exports.default.fetch(
+					`${ORIGIN}/player/connection-info?roomInstanceId=${roomInstanceId}`,
+					{ headers: await bearer(player) }
+				)
+				const body = (await res.json()) as {
+					value: { voiceConnectionInfo: string; voiceServerId: string }
+				}
+				return {
+					voiceConnectionInfo: body.value.voiceConnectionInfo,
+					voiceServerId: body.value.voiceServerId,
+				}
+			}
+
+			const instance = await createRoomInstance(env.DB, {
+				ownerAccountId: 974,
+				roomId: 2,
+				photonRoomId: 'tachyon-instance-dev',
+				maxCapacity: 12,
+			})
+			expect(await voiceFor('974', instance.roomInstanceId)).toEqual({
+				voiceConnectionInfo: '198.51.100.12:7778',
+				voiceServerId: 'dev',
+			})
+			// Everyone else in that instance keeps the pool entry's own port and id.
+			expect(await voiceFor('975', instance.roomInstanceId)).toEqual({
+				voiceConnectionInfo: '198.51.100.12:7777',
+				voiceServerId: 'tachyon-1',
+			})
+
+			// In no instance there is no server to move the port of: a bare ':7778' would be
+			// an address that answers nothing, named `dev`.
+			const none = await exports.default.fetch(`${ORIGIN}/player/connection-info`, {
+				headers: await bearer('974'),
+			})
+			const body = (await none.json()) as {
+				value: { voiceConnectionInfo: string; voiceServerId: string }
+			}
+			expect(body.value.voiceConnectionInfo).toBe('')
+			expect(body.value.voiceServerId).toBe('')
+		} finally {
+			env.TACHYON_HOST_PORT = original
+		}
+	})
+
 	test('re-matchmaking into your current room returns a different instance (id must change)', async () => {
 		// The client keys the room transition off a changing roomInstanceId; handing back
 		// the instance the player is already in hangs their join. RecCenter (cap 12) so