@demystify/gateway-moat

Model routing, rate limiting, budgets and a usage ledger — as a library.

Serverless: import /core

import {
  Router, ProviderHealthTracker, RateLimiter, BudgetService,
  UsageService, KeysService, MemoryRepo, MemoryLimitStore,
  MockBackend, InMemoryEventBus, SystemClock, DEFAULT_ROUTER_CONFIG,
} from "@demystify/gateway-moat/core";

/core has no Hono, no ioredis, no pg. hono, @hono/node-server, ioredis and pg are optionalDependencies used only by the service entry points, so a Vercel or Lambda bundle that imports /core does not carry a Redis client it has no use for.

The package root re-exports createApp, which pulls the HTTP layer in — that is what made an earlier version unusable on serverless. Import the subpath.

What it gives you

| Concern | Class | |---|---| | Alias chains + failover on 429/5xx/timeout | Router | | Circuit breaker with cooldown and probe | ProviderHealthTracker | | Reservation-based rate limiting | RateLimiter | | Reserve → settle spend ceilings | BudgetService | | Append-only ledger, integer µUSD | UsageService | | Per-tenant virtual keys (dmk_ + 32 hex) | KeysService | | Exact + semantic response caching | SemanticCacheService |

Every one works with the in-memory adapters and needs no infrastructure: MemoryRepo, MemoryLimitStore, MemoryQueueStore, MemorySemanticCache, InMemoryEventBus, MockBackend.

Entry points

| Subpath | For | |---|---| | /core | serverless and libraries — pure, no service deps | | . | everything, including createApp (drags in Hono) | | /server | running the gateway as a service |

What it does NOT do

• It is not a hosted service. Nothing is deployed; you run what you need.
• The Postgres and Redis adapters are opt-in and live behind the optional deps.
• Money is integer micro-USD. UsageService.record rejects a non-integer cost rather than rounding it.

MIT.