Interactive demos for Vercel Workflow DevKit — each showcasing a different durable workflow pattern built with Next.js 16, React 19, and the workflow package.
| # | Demo | Pattern | v0 Link |
|---|---|---|---|
| 1 | Approval Gate | Human-in-the-loop with timeout | Open in v0 |
| 2 | Onboarding Drip | 7-day email drip in 6 lines | Open in v0 |
| 3 | Saga | Step 3 fails — compensating rollbacks | Open in v0 |
| 4 | Cancellable Export | Cancel a batch mid-flight | Open in v0 |
Turborepo has already landed the big algorithmic win — topological-wave parallel task hashing (commit b3c0f46da8) — but several implementation details are now the bottleneck:
Parallelism is re-serialized by shared locks + deep clones: TaskHashTrackerState uses one RwLock guarding 6 independent HashMaps (crates/turborepo-task-hash/src/lib.rs:226-242), so any insert_hash() write blocks all concurrent reads. The visitor's wave-hashing funnels results through Arc<Mutex<HashMap>> with per-wave serialization (crates/turborepo-lib/src/task_graph/visitor/mod.rs:233-303).
Allocation hot-loops dominate hash & dispatch: DetailedMap (3 nested HashMaps) deep-cloned on every env_vars() read (line 622). EnvironmentVariableMap cloned per task at line 388. Repeated regex compilations for env patterns (4 per task in hashable_task_env) and glob patterns (O(packages) recompilations). SCM hashing allocates 10,000+ hex Strings inside parallel loops.
**I/O paths lea
You deploy OpenClaw (an AI gateway) inside a Vercel Sandbox and connect it to Telegram. Users chat with the bot. Everything works great — until someone says:
"Text me a silly joke every 5 minutes"
The bot tries to create a scheduled task (a cron job). It fails:
tl;dr for boss
{key}.basedomain.com) already solves that--skip-channels, use long polling mode so the Gateway polls Telegram itself. No webhook URLs needed. Downside: bot appears offline when sandbox is stopped, no way to send "booting up..." messages to users--skip-channels, add /api/webhooks/telegram on our always-on Next.js app. Queue messages in Redis, trigger restore, send "booting up..." progress messages, drain queue once sandbox is live. More code but full control over cold-start experience
{key}.basedomain.com) survives sandbox restarts/api/webhooks/telegram (and /slack) endpoints that return 200 OK immediately and queue messages in Redissandbox.domain(3000) + gateway token — skip the proxy and password gate entirely
Before: "ZERO file reads" — absolute ban on all file reads. After: "NO source file reads" — nuanced rule with explicit allowlist.
| Scenario | Before (broke rule) | After (legitimate) |
|---|---|---|
git diff --stat after workers finish |
❌ Violated "ZERO file reads" | ✅ Explicitly allowed |
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