✨ feat(server): add IPC JSON-RPC transport

[roninjin10]

Bug

@tevm/server only exposed an HTTP JSON-RPC server, so Node clients using viem's ipc() transport had no Unix domain socket endpoint to connect to. A test importing createIpcServer was written first and reproduced the missing public API.

This closes the viem migration blocker described as:

"WebSocket and IPC transports ... still need it [anvil]."

Root cause

The server package had no node:net server, stream framing, or persistent connection layer. Although Tevm's JSON-RPC actions can create subscriptions, there was also no transport adapter to forward node events as eth_subscription notifications or clean them up when a connection closes.

Fix

• Add public createIpcServer API backed by a Unix domain socket.
• Parse fragmented, concatenated, and newline-delimited JSON-RPC frames safely across UTF-8 chunks.
• Route regular, batch, and notification requests through the existing Tevm JSON-RPC dispatcher.
• Stream newHeads, newPendingTransactions, and filtered logs subscription notifications.
• Clean up subscription filters and event listeners on eth_unsubscribe or socket close.
• Add configurable message and batch limits, public barrel exports, documentation, and a changeset.

Tests

• pnpm vitest run packages/server/src/createIpcServer.spec.ts — 9 passed.
• pnpm --dir packages/server typecheck — passed.
• pnpm --dir packages/server lint:check — passed.
• pnpm --dir packages/server build:dist and pnpm --dir packages/server build:types — passed.

The IPC integration tests use real Unix sockets, a real Tevm memory client, and viem's real ipc() transport. They cover request/response framing, invalid requests, batches, notifications, size limits, all supported subscription types, filtering, unsubscribe behavior, and connection cleanup without mocks.

The full neighboring server run completed with 67 passing and 2 failing tests. Both failures are newly landed parseRequest.spec.ts exact-message assertions already present on origin/main; this branch has no diff in either parseRequest.js or parseRequest.spec.ts. On the original requested clone base, the neighboring server suite passed all 65 tests and the coverage run passed every configured threshold (87.52% statements, 81.02% branches, 91.25% functions, 89.3% lines).

Add a Unix domain socket JSON-RPC server to packages/server with newline-delimited framing and subscription support so viem's ipc() transport can use Tevm instead of Anvil.

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Latest commit: 25bb2c5

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Project	Deployment	Actions	Updated (UTC)
node	Ready	Preview	Jul 30, 2026 1:15am
tevm-monorepo-app	Ready	Preview	Jul 30, 2026 1:15am

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
tevm-monorepo-tevm	Ignored		Jul 30, 2026 1:15am

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📥 Commits

Reviewing files that changed from the base of the PR and between 846b040 and 25bb2c5.

⛔ Files ignored due to path filters (1)

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📒 Files selected for processing (12)

• .changeset/fresh-sockets-listen.md
• .changeset/ipc-server.md
• packages/server/README.md
• packages/server/package.json
• packages/server/src/createIpcServer.js
• packages/server/src/createIpcServer.spec.ts
• packages/server/src/index.js
• packages/server/src/index.spec.ts
• packages/server/src/index.ts
• packages/server/src/internal/createIpcConnectionHandler.js
• packages/server/src/internal/createIpcSubscription.js
• packages/server/src/internal/extractJsonRpcFrames.js

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[roninjin10]

Blocking transport findings:

1. packages/server/src/internal/createIpcSubscription.js:49-115 pushes events but never drains the node filter that eth_subscribe created. Those filters continue buffering every block/log/transaction for polling even though IPC has already pushed each event. I reproduced this with a newHeads subscription: after three delivered blocks, filter.blocks.length was 3. It therefore grows without bound for a long-lived IPC connection. The WebSocket PR explicitly adds drainFilter for this reason, so the two transports are already inconsistent. Move subscription binding/draining into a shared helper and clear the relevant filter buffers as notifications are delivered.

2. createIpcConnectionHandler.js:43-65 dispatches eth_unsubscribe to the global node before checking ownership in the connection-local subscriptions map. A different IPC connection can therefore unsubscribe a subscription it does not own; its local listener is not removed, while the owning connection can keep receiving events for a filter the node considers deleted. Check subscriptions.has(id) before dispatch and return false for foreign IDs, matching the connection-scoped behavior implemented in ✨ feat(server): add WebSocket JSON-RPC transport with eth_subscribe support #2084.

3. Notification subscriptions leak completely. dispatch calls handleBulkRequest(..., { suppressNotifications: true }); an eth_subscribe request with no id still creates the node filter, but its response is suppressed, so lines 45-53 never record the ID and socket cleanup can never unsubscribe it. Either reject eth_subscribe notifications before dispatch or capture and immediately dispose the created subscription.

4. A syncing subscription returns an ID, but createIpcSubscription falls through the default branch and never emits a notification. The current test only proves that the filter is deleted on close, not that the advertised subscription works. ✨ feat(server): add WebSocket JSON-RPC transport with eth_subscribe support #2084 implements initial and transition notifications, which is another reason this logic should be shared and tested once across both transports.