diff --git a/packages/lib/Tools.ts b/packages/lib/Tools.ts
index 18d2f56..d278fb6 100644
--- a/packages/lib/Tools.ts
+++ b/packages/lib/Tools.ts
@@ -130,6 +130,18 @@ export const ensurePlural = <T>(x: T | T[]) => (x instanceof Array ? x : [x])
 
 export const ensureNumber = (x: number | string) => parseFloat(x as string)
 
+export const fromPairs = <T>(pairs: [k?: string, v?: T, ...args: unknown[]][]) => {
+  const r: Record<string, T> = {}
+
+  for (const [k, v] of pairs) {
+    if (k && v) {
+      r[k] = v
+    }
+  }
+
+  return r
+}
+
 export const flatten = <T>(xs: T[][]) => xs.flatMap(identity)
 
 export const partition = <T>(f: (x: T) => boolean, xs: T[]) => {
diff --git a/packages/util/Relay.ts b/packages/util/Relay.ts
index 51e9c69..2991c5a 100644
--- a/packages/util/Relay.ts
+++ b/packages/util/Relay.ts
@@ -1,40 +1,14 @@
-import type {Readable, Subscriber, Invalidator} from '@welshman/lib'
-import {Derived, Emitter, randomId, chunk, sleep, uniq, omit, now, range, identity} from '@welshman/lib'
-import {matchFilters, matchFilter} from './Filters'
-import {encodeAddress, addressFromEvent} from './Address'
-import {isReplaceable} from './Events'
+import {Emitter} from '@welshman/lib'
+import {matchFilters} from './Filters'
+import type {Repository} from './Repository'
 import type {Filter} from './Filters'
 import type {Rumor} from './Events'
 
-export const DAY = 86400
-
-const getDay = (ts: number) => Math.floor(ts / DAY)
-
-export type Message = [string, ...any[]]
-
 export class Relay<E extends Rumor> extends Emitter {
-  eventsById = new Map<string, E>()
-  eventsByAddress = new Map<string, E>()
-  eventsByTag = new Map<string, E[]>()
-  eventsByDay = new Map<number, E[]>()
-  eventsByAuthor = new Map<string, E[]>()
-  deletes = new Map<string, number>()
   subs = new Map<string, Filter[]>()
 
-  dump() {
-    return Array.from(this.eventsById.values())
-  }
-
-  async load(events: E[], chunkSize = 1000) {
-    for (const eventsChunk of chunk(chunkSize, events)) {
-      for (const event of eventsChunk) {
-        this._addEvent(event)
-      }
-
-      if (eventsChunk.length === chunkSize) {
-        await sleep(1)
-      }
-    }
+  constructor(readonly repository: Repository<E>) {
+    super()
   }
 
   send(type: string, ...message: any[]) {
@@ -45,38 +19,6 @@ export class Relay<E extends Rumor> extends Emitter {
     }
   }
 
-  has(id: string) {
-    return this.eventsById.has(id)
-  }
-
-  get(id: string) {
-    return this.eventsById.get(id)
-  }
-
-  put(event: E) {
-    const duplicateById = this.eventsById.get(event.id)
-
-    if (duplicateById) {
-      return false
-    }
-
-    const hasAddress = isReplaceable(event)
-    const address = encodeAddress(addressFromEvent(event))
-    const duplicateByAddress = hasAddress ? this.eventsByAddress.get(address) : undefined
-
-    if (duplicateByAddress && duplicateByAddress.created_at >= event.created_at) {
-      return false
-    }
-
-    this._addEvent(event, duplicateByAddress)
-
-    return true
-  }
-
-  cursor(filters: Filter[]) {
-    return new RelayCursor(this, filters)
-  }
-
   handleEVENT([json]: [string]) {
     let event: E
     try {
@@ -85,11 +27,13 @@ export class Relay<E extends Rumor> extends Emitter {
       return
     }
 
-    const added = this.put(event)
+    this.repository.publish(event)
 
     this.emit('OK', event.id, true, "")
 
-    if (added && !this._isDeleted(event)) {
+    if (!this.repository.isDeleted(event)) {
+      const json = JSON.stringify(event)
+
       for (const [subId, filters] of this.subs.entries()) {
         if (matchFilters(filters, event)) {
           this.emit('EVENT', subId, json)
@@ -105,151 +49,10 @@ export class Relay<E extends Rumor> extends Emitter {
   handleREQ([subId, ...filters]: [string, ...Filter[]]) {
     this.subs.set(subId, filters)
 
-    const result = new Set()
-
-    for (let filter of filters) {
-      let events: Iterable<E> = this.eventsById.values()
-
-      if (filter.ids) {
-        filter = omit(['ids'], filter)
-        events = filter.ids!.map(id => this.eventsById.get(id)).filter(identity) as E[]
-      } else if (filter.authors) {
-        filter = omit(['authors'], filter)
-        events = uniq(filter.authors!.flatMap(pubkey => this.eventsByAuthor.get(pubkey) || []))
-      } else if (filter.since || filter.until) {
-        const sinceDay = getDay(filter.since || 0)
-        const untilDay = getDay(filter.since || now())
-
-        filter = omit(['since', 'until'], filter)
-        events = uniq(
-          Array.from(range(sinceDay, untilDay))
-            .flatMap((day: number) => this.eventsByDay.get(day) || [])
-        )
-      } else {
-        for (const [k, values] of Object.entries(filter)) {
-          if (!k.startsWith('#') || k.length !== 2) {
-            continue
-          }
-
-          filter = omit([k], filter)
-          events = uniq(
-            (values as string[]).flatMap(v => this.eventsByTag.get(`${k[1]}:${v}`) || [])
-          )
-
-          break
-        }
-      }
-
-      for (const event of events) {
-        if (!this._isDeleted(event) && matchFilter(filter, event)) {
-          result.add(event)
-        }
-      }
-    }
-
-    for (const event of result) {
+    for (const event of this.repository.query(filters)) {
       this.emit('EVENT', subId, JSON.stringify(event))
     }
 
     this.emit('EOSE', subId)
   }
-
-  _isDeleted(event: E) {
-    const idDeletedAt = this.deletes.get(event.id) || 0
-
-    if (idDeletedAt > event.created_at) {
-      return true
-    }
-
-    if (isReplaceable(event)) {
-      const address = encodeAddress(addressFromEvent(event))
-      const addressDeletedAt = this.deletes.get(address) || 0
-
-      if (addressDeletedAt > event.created_at) {
-        return true
-      }
-    }
-
-    return false
-  }
-
-  _addEvent(event: E, duplicate?: E) {
-    this.eventsById.set(event.id, event)
-
-    if (isReplaceable(event)) {
-      this.eventsByAddress.set(encodeAddress(addressFromEvent(event)), event)
-    }
-
-    this._updateIndex(this.eventsByDay, getDay(event.created_at), event, duplicate)
-    this._updateIndex(this.eventsByAuthor, event.pubkey, event, duplicate)
-
-    for (const tag of event.tags) {
-      if (tag[0].length === 1) {
-        this._updateIndex(this.eventsByTag, tag.slice(0, 2).join(':'), event, duplicate)
-
-        if (event.kind === 5) {
-          this.deletes.set(tag[1], Math.max(event.created_at, this.deletes.get(tag[1]) || 0))
-        }
-      }
-    }
-  }
-
-  _updateIndex<K>(m: Map<K, E[]>, k: K, e: E, duplicate?: E) {
-    let a = m.get(k) || []
-
-    if (duplicate) {
-      a = a.filter((x: E) => x !== duplicate)
-    }
-
-    a.push(e)
-    m.set(k, a)
-  }
-}
-
-type Sub<E> = (events: E[]) => void
-
-export class RelayCursor<E extends Rumor> implements Readable<E[]> {
-  subId = randomId()
-  subs: Sub<E>[] = []
-  events: E[] = []
-
-  constructor(readonly relay: Relay<E>, readonly filters: Filter[]) {
-    this.relay.on('EVENT', (e: E) => {
-      this.events.push(e)
-      this.notify()
-    })
-
-    this.relay.handleREQ([this.subId, ...this.filters])
-  }
-
-  get() {
-    return this.events
-  }
-
-  subscribe(f: Subscriber<E[]>, invalidate?: Invalidator<E[]>) {
-    this.subs.push(f)
-
-    return () => {
-      this.subs = this.subs.filter(sub => sub !== f)
-    }
-  }
-
-  derived<U>(f: (v: E[]) => U): Derived<U> {
-    return new Derived<U>(this, f)
-  }
-
-  throttle(t: number): Derived<E[]> {
-    return new Derived<E[]>(this, identity, t)
-  }
-
-  notify() {
-    for (const sub of this.subs) {
-      sub(this.events)
-    }
-  }
-
-  close() {
-    this.relay.handleCLOSE([this.subId])
-    this.subs = []
-  }
 }
diff --git a/packages/util/Repository.ts b/packages/util/Repository.ts
new file mode 100644
index 0000000..56893f7
--- /dev/null
+++ b/packages/util/Repository.ts
@@ -0,0 +1,199 @@
+import type {Readable, Subscriber, Invalidator} from '@welshman/lib'
+import {Derived, chunk, sleep, uniq, omit, now, range, identity} from '@welshman/lib'
+import {matchFilter} from './Filters'
+import {encodeAddress, addressFromEvent} from './Address'
+import {isReplaceable} from './Events'
+import type {Filter} from './Filters'
+import type {Rumor} from './Events'
+
+export const DAY = 86400
+
+const getDay = (ts: number) => Math.floor(ts / DAY)
+
+export class Repository<E extends Rumor> implements Readable<Repository<E>> {
+  eventsById = new Map<string, E>()
+  eventsByAddress = new Map<string, E>()
+  eventsByTag = new Map<string, E[]>()
+  eventsByDay = new Map<number, E[]>()
+  eventsByAuthor = new Map<string, E[]>()
+  deletes = new Map<string, number>()
+  subs: Subscriber<typeof this>[] = []
+
+  // Methods for implementing store interface
+
+  get() {
+    return this
+  }
+
+  subscribe(f: Subscriber<Repository<E>>, invalidate?: Invalidator<Repository<E>>) {
+    this.subs.push(f)
+
+    return () => {
+      this.subs = this.subs.filter(sub => sub !== f)
+    }
+  }
+
+  derived<U>(f: (v: Repository<E>) => U): Derived<U> {
+    return new Derived<U>(this, f)
+  }
+
+  throttle(t: number): Derived<Repository<E>> {
+    return new Derived<Repository<E>>(this, identity, t)
+  }
+
+  notify() {
+    for (const sub of this.subs) {
+      sub(this)
+    }
+  }
+
+  // Load/dump
+
+  dump() {
+    return Array.from(this.eventsById.values())
+  }
+
+  async load(events: E[], chunkSize = 1000) {
+    for (const eventsChunk of chunk(chunkSize, events)) {
+      for (const event of eventsChunk) {
+        this._addEvent(event)
+      }
+
+      if (eventsChunk.length === chunkSize) {
+        await sleep(1)
+      }
+    }
+
+    this.notify()
+  }
+
+  // API
+
+  getEvent(idOrAddress: string) {
+    return idOrAddress.includes(':')
+      ? this.eventsByAddress.get(idOrAddress)
+      : this.eventsById.get(idOrAddress)
+  }
+
+  *query(filters: Filter[]) {
+    for (let filter of filters) {
+      let events: Iterable<E> = this.eventsById.values()
+
+      if (filter.ids) {
+        filter = omit(['ids'], filter)
+        events = filter.ids!.map(id => this.eventsById.get(id)).filter(identity) as E[]
+      } else if (filter.authors) {
+        filter = omit(['authors'], filter)
+        events = uniq(filter.authors!.flatMap(pubkey => this.eventsByAuthor.get(pubkey) || []))
+      } else if (filter.since || filter.until) {
+        const sinceDay = getDay(filter.since || 0)
+        const untilDay = getDay(filter.since || now())
+
+        filter = omit(['since', 'until'], filter)
+        events = uniq(
+          Array.from(range(sinceDay, untilDay))
+            .flatMap((day: number) => this.eventsByDay.get(day) || [])
+        )
+      } else {
+        for (const [k, values] of Object.entries(filter)) {
+          if (!k.startsWith('#') || k.length !== 2) {
+            continue
+          }
+
+          filter = omit([k], filter)
+          events = uniq(
+            (values as string[]).flatMap(v => this.eventsByTag.get(`${k[1]}:${v}`) || [])
+          )
+
+          break
+        }
+      }
+
+      for (const event of events) {
+        if (!this.isDeleted(event) && matchFilter(filter, event)) {
+          yield event
+        }
+      }
+    }
+  }
+
+  publish(event: E) {
+    const duplicateById = this.eventsById.get(event.id)
+
+    if (duplicateById) {
+      return false
+    }
+
+    const hasAddress = isReplaceable(event)
+    const address = encodeAddress(addressFromEvent(event))
+    const duplicateByAddress = hasAddress ? this.eventsByAddress.get(address) : undefined
+
+    if (duplicateByAddress && duplicateByAddress.created_at >= event.created_at) {
+      return false
+    }
+
+    this._addEvent(event, duplicateByAddress)
+
+    return true
+  }
+
+  isDeleted(event: E) {
+    const idDeletedAt = this.deletes.get(event.id) || 0
+
+    if (idDeletedAt > event.created_at) {
+      return true
+    }
+
+    if (isReplaceable(event)) {
+      const address = encodeAddress(addressFromEvent(event))
+      const addressDeletedAt = this.deletes.get(address) || 0
+
+      if (addressDeletedAt > event.created_at) {
+        return true
+      }
+    }
+
+    return false
+  }
+
+  // Implementation
+
+  _addEvent(event: E, duplicate?: E) {
+    this.eventsById.set(event.id, event)
+
+    if (isReplaceable(event)) {
+      this.eventsByAddress.set(encodeAddress(addressFromEvent(event)), event)
+    }
+
+    this._updateIndex(this.eventsByDay, getDay(event.created_at), event, duplicate)
+    this._updateIndex(this.eventsByAuthor, event.pubkey, event, duplicate)
+
+    for (const tag of event.tags) {
+      if (tag[0].length === 1) {
+        this._updateIndex(this.eventsByTag, tag.slice(0, 2).join(':'), event, duplicate)
+
+        if (event.kind === 5) {
+          const id = tag[1]
+          const ts = Math.max(event.created_at, this.deletes.get(tag[1]) || 0)
+
+          this.deletes.set(id, ts)
+        }
+      }
+    }
+
+    if (!this.isDeleted(event)) {
+      this.notify()
+    }
+  }
+
+  _updateIndex<K>(m: Map<K, E[]>, k: K, e: E, duplicate?: E) {
+    let a = m.get(k) || []
+
+    if (duplicate) {
+      a = a.filter((x: E) => x !== duplicate)
+    }
+
+    a.push(e)
+    m.set(k, a)
+  }
+}
diff --git a/packages/util/index.ts b/packages/util/index.ts
index 759f806..8bb1533 100644
--- a/packages/util/index.ts
+++ b/packages/util/index.ts
@@ -5,6 +5,7 @@ export * from './Kinds'
 export * from './Links'
 export * from './Relay'
 export * from './Relays'
+export * from './Repository'
 export * from './Router'
 export * from './Tags'
 export * from './Zaps'