@1001-digital/proxies

Ethereum proxy pattern detection primitives for TypeScript — ERC-2535 diamonds, EIP-1967, EIP-1167, beacon, Safe, EIP-1822, EIP-897.

Given a contract address, resolve where the real code lives: one implementation (plain proxy) or N facets (diamond). Uniform detect → enrich → compose pipeline across all patterns.

Narrow on purpose: this package knows proxy conventions, selectors, and ABIs. Anything richer — Sourcify, NatSpec, repository metadata — is the consumer's concern. Bring your own enricher.

Who this is for

Use this package when you need a small, composable proxy-resolution layer in:

• explorer and indexer backends
• contract introspection CLIs
• ABI fetchers and decoding pipelines
• developer tooling that needs implementation or facet discovery without owning proxy-specific logic

What this package is not

This package intentionally does not try to be:

• a contract metadata SDK
• a verification or source-code retrieval client
• a recursive proxy resolver
• an upgrade history tracker
• an opinionated registry or indexing layer

If you need sources, NatSpec, repository metadata, verification status, or custom per-target fields, use detect() and own enrichment yourself.

Install

pnpm add @1001-digital/proxies

Usage

Detect + fetch a proxy

import { createProxies } from '@1001-digital/proxies'

const proxies = createProxies()

const result = await proxies.fetch(
  'https://eth.llamarpc.com',
  '0xProxyAddress…',
)

if (result) {
  console.log(result.pattern)        // 'eip-1967' | 'eip-2535-diamond' | …
  console.log(result.targets)        // [{ address, selectors?, abi? }, …]
  console.log(result.compositeAbi)   // undefined — no enricher configured
}

Enrich with Sourcify (or anything else)

The enricher returns each target's ABI. Anything richer (sources, bytecode, documentation, …) is the consumer's concern — see Detect and do your own enrichment below.

import { createProxies } from '@1001-digital/proxies'

async function sourcifyAbi(address: string) {
  const res = await fetch(
    `https://sourcify.dev/server/v2/contract/1/${address}?fields=abi`,
  )
  if (!res.ok) return null
  const { abi } = await res.json()
  return { abi }
}

const proxies = createProxies({ enrich: sourcifyAbi })

const result = await proxies.fetch(
  'https://eth.llamarpc.com',
  '0xProxyAddress…',
)

if (result) {
  console.log(result.targets[0].abi) // ABI (filtered to selectors for diamonds, full for plain proxies)
  console.log(result.compositeAbi)   // all target ABIs deduped by selector
}

Detect and do your own enrichment

For richer per-target metadata, use detect and own the enrichment step end-to-end. filterAbiBySelectors and buildCompositeAbi remain useful primitives.

import {
  createProxies,
  filterAbiBySelectors,
  buildCompositeAbi,
} from '@1001-digital/proxies'

const proxies = createProxies()
const raw = await proxies.detect(rpc, address)

if (raw) {
  const enriched = await Promise.all(raw.targets.map(async t => {
    const src = await mySource(t.address)
    return {
      ...t,
      abi: src?.abi && t.selectors
        ? filterAbiBySelectors(src.abi, t.selectors)
        : src?.abi,
      metadata: src?.metadata,
    }
  }))

  const compositeAbi = buildCompositeAbi(
    enriched.map(t => t.abi).filter((a): a is unknown[] => !!a),
  )
}

Standalone primitives

All low-level utilities are exported directly — use them without the factory:

import {
  detectProxy,
  detectDiamond,
  detectEip1967,
  decodeFacets,
  computeSelector,
  canonicalSignature,
  filterAbiBySelectors,
  buildCompositeAbi,
  enrichTargets,
} from '@1001-digital/proxies'

decodeFacets('0x…')                            // parse a facets() return value
computeSelector('transfer(address,uint256)')   // '0xa9059cbb'
canonicalSignature({ type: 'function', name: 'transfer', inputs: [/*…*/] })

API

createProxies(config?)

Creates a proxies client.

Config options:

Option	Type	Default	Description
enrich	TargetEnricher	—	Default per-target enricher. Called with each target address; return { abi? } or null. Errors are swallowed per-target.
fetch	typeof fetch	globalThis.fetch	Custom fetch function.

Returns a ProxiesClient with:

• detect(rpc, address) — Promise<RawProxy | null>. On-chain probe only.
• fetch(rpc, address, options?) — Promise<Proxy | null>. Detect, enrich, and compose.
  • options.enrich — per-call enricher (overrides config-level)
  • options.enrich = false — skip enrichment for this call

Detection

• detectProxy(rpc, address, fetchFn) — tries all patterns in priority order (diamond → 1967 → 1967-beacon → 1822 → 1167 → safe → 897), returns the first match.
• detectDiamond — ERC-165 probe, then facets() fallback.
• detectEip1967 — reads impl slot 0x3608…3bc3; optionally admin slot.
• detectEip1967Beacon — reads beacon slot 0xa3f0…750d, then implementation() on the beacon.
• detectEip1822 — reads PROXIABLE slot 0xc5f1…f8e2.
• detectEip1167 — eth_getCode, matches minimal proxy bytecode (363d3d…bf3).
• detectGnosisSafe — reads storage slot 0.
• detectEip897 — calls implementation() as a last resort.

Each detector returns null if the pattern doesn't match; otherwise a RawProxy.

Detection tradeoffs

• First match wins — detector order is intentional. If a contract could satisfy multiple heuristics, detectProxy returns the first supported pattern in priority order.
• Single-hop resolution — if a resolved implementation is itself a proxy, detection stops there. Beacon remains supported as a defined two-step pattern.
• Error isolation — one failed RPC probe does not poison the full detection pipeline.

Composition

• enrichTargets(targets, enricher | null) — applies the enricher to each target; ABIs are filtered to live selectors for diamonds, passed through for plain proxies.
• buildCompositeAbi(abis) — pure; dedupes functions/events/errors across ABIs (first-wins).

Utilities

• decodeFacets(hex) — pure; decodes (address, bytes4[])[] loupe return.
• computeSelector(signature) — pure; keccak256-based 4-byte selector.
• canonicalSignature(abiEntry) — pure; normalizes tuples/arrays into a signature string.
• filterAbiBySelectors(abi, selectors) — pure; keeps non-functions, filters functions by selector.
• ethCall, ethGetStorageAt, ethGetCode — minimal JSON-RPC helpers.

Constants

SUPPORTS_INTERFACE_SELECTOR      // '0x01ffc9a7'
DIAMOND_LOUPE_INTERFACE_ID       // '0x48e2b093'
FACETS_SELECTOR                  // '0x7a0ed627'
IMPLEMENTATION_SELECTOR          // '0x5c60da1b'
EIP1967_IMPL_SLOT
EIP1967_BEACON_SLOT
EIP1967_ADMIN_SLOT
EIP1822_PROXIABLE_SLOT
EIP1167_BYTECODE_PREFIX
EIP1167_BYTECODE_SUFFIX
ZERO_ADDRESS

Errors

• ProxiesError — base class.
• ProxiesDecodeError — malformed facets() return.
• ProxiesFetchError — JSON-RPC transport error.

The client's detect and fetch methods swallow RPC-layer errors and return null; only decodeFacets (called directly) can throw ProxiesDecodeError on malformed input.

Shapes

ProxyPattern

type ProxyPattern =
  | 'eip-2535-diamond'
  | 'eip-1967'
  | 'eip-1967-beacon'
  | 'eip-1822'
  | 'eip-1167'
  | 'gnosis-safe'
  | 'eip-897'

ResolvedTarget

{
  address: string
  // undefined = all selectors route here (plain proxy)
  // defined = diamond facet selector scope
  selectors?: string[]
}

RawProxy

{
  pattern: ProxyPattern
  targets: ResolvedTarget[]   // 1 entry except for diamonds
  beacon?: string             // only for eip-1967-beacon
  admin?: string              // only for eip-1967 when admin slot is set
}

EnrichedTarget

{
  address: string
  selectors?: string[]
  abi?: unknown[]
}

Proxy

{
  pattern: ProxyPattern
  targets: EnrichedTarget[]
  beacon?: string
  admin?: string
  compositeAbi?: unknown[]   // deduped by selector
}

TargetEnrichment

{ abi?: unknown[] }

TargetEnricher

type TargetEnricher = (address: string) => Promise<TargetEnrichment | null>

Design notes

• Narrow scope — detects patterns and composes ABIs; no opinion on documentation formats or richer per-target metadata.
• Dependency-injected enrichment — the factory wires I/O when you ask; the primitives work offline.
• First-wins ABI dedup — pass the most authoritative ABI first (e.g. main contract → impl, or main diamond → facets).
• Single-hop resolution — if a resolved implementation is itself a proxy, detectProxy does not recurse. Beacon stays supported as a defined two-step pattern.
• Minimal runtime deps — only @noble/hashes for keccak256.

Example consumers

• An explorer backend can call detect() to resolve a proxy and then enrich targets from Sourcify or an internal cache.
• A CLI can call fetch() to print the detected pattern, target addresses, and a composite ABI for downstream decoding.
• An indexing pipeline can treat detectProxy → enrichTargets → buildCompositeAbi as a reusable normalization step before storage.

License

MIT