Pathfinder

Circles pathfinder calculates “how much and through which tokens can flow from A to B” based on trust and balances (wrapped and unwrapped). You can use it to:

• Preview a route and achievable amount.

• Feed TransferBuilder or custom operateFlowMatrix calls.

Entry points

• High-level SDK: const rpc = (sdk as any).rpc; rpc.pathfinder.findPath / findMaxFlow

• Standalone: const rpc = new CirclesRpc(config.circlesRpcUrl);

Methods

• findPath(params: FindPathParams): Promise<PathfindingResult>

• findMaxFlow(params: Omit<FindPathParams, 'targetFlow'>): Promise<bigint>

Parameters (FindPathParams)

• from (Address, required): Source avatar.

• to (Address, required): Destination avatar.

• targetFlow (bigint, required for findPath): Desired amount.

• useWrappedBalances (boolean, optional): Allow ERC20 wrappers in the route. Set true if you hold wrapped CRC.

• fromTokens / toTokens (Address[], optional): Only allow these token owners from sender/recipient sides.

• excludeFromTokens / excludeToTokens (Address[], optional): Ban specific token owners.

• simulatedBalances (array, optional): Inject hypothetical balances { holder, token, amount, isWrapped, isStatic }.

• maxTransfers (number, optional): Hop cap; lower = faster, but may reduce flow.

findPath (targeted route)

Computes a path for a requested amount; returns what is actually achievable plus hop-by-hop legs.

import { CirclesRpc } from '@aboutcircles/sdk-rpc';

const rpc = new CirclesRpc('https://rpc.circlesubi.network/');

const path = await rpc.pathfinder.findPath({
  from: '0xSender',
  to: '0xRecipient',
  targetFlow: BigInt('10000000000000000000'), // 10 CRC
  useWrappedBalances: true,
  fromTokens: ['0xPreferredToken'],  // optional pin
  excludeToTokens: ['0xAvoidToken'], // optional ban
  maxTransfers: 4
});

console.log(path.maxFlow);    // bigint achievable
console.log(path.transfers);  // [{ from, to, tokenOwner, value }]

PathfindingResult:

• maxFlow – achievable flow for this request.

• transfers – ordered legs; tokenOwner is the ERC1155 owner or wrapper used in that hop.

If maxFlow < targetFlow, decide to scale down or show an error.

findMaxFlow (ceiling)

Returns the absolute maximum possible flow between two avatars with the same options.

const max = await rpc.pathfinder.findMaxFlow({
  from: '0xSender',
  to: '0xRecipient',
  useWrappedBalances: true,
  simulatedBalances: [
    { holder: '0xSender', token: '0xToken', amount: 5n * 10n ** 18n, isWrapped: false, isStatic: false }
  ],
});

Use for sliders, validation, or deciding if you must unwrap/wrap first.

Advanced usage

• Wrapped tokens: useWrappedBalances: true enables consuming inflationary/demurraged ERC20 wrappers the sender holds.

• Token pinning/bans: Use fromTokens/toTokens to force specific personal or group tokens; use the exclude* variants to forbid costly or undesired wrappers.

• Simulations: simulatedBalances let you preview flows after an expected mint/wrap without waiting for indexer updates.

• Hop limit: maxTransfers curbs route length; helpful for UX responsiveness but may lower maxFlow.

From path to execution

• Easiest: call TransferBuilder.constructAdvancedTransfer(from, to, amount, options)—it runs findPath, adds unwrap/rewrap, approvals, and returns an ordered tx array.

• Manual: convert PathfindingResult to operateFlowMatrix:

import { createFlowMatrix } from '@aboutcircles/sdk-pathfinder';
import { Core } from '@aboutcircles/sdk-core';

const core = new Core();
const rpc = new CirclesRpc(core.config.circlesRpcUrl);

const path = await rpc.pathfinder.findPath({ from, to, targetFlow, useWrappedBalances: true });
const flow = createFlowMatrix(from, to, path.maxFlow, path.transfers);

const tx = core.hubV2.operateFlowMatrix(
  flow.flowVertices,
  flow.flowEdges,
  flow.streams,
  flow.packedCoordinates
);
// send tx via your runner

Pathfinder helper functions (when you build flows yourself)

• createFlowMatrix(from, to, maxFlow, transfers) – turns a PathfindingResult into flowVertices, flowEdges, streams, packedCoordinates for hubV2.operateFlowMatrix.

• packCoordinates(flowVertices) / transformToFlowVertices(transfers) – lower-level helpers used by createFlowMatrix for packing vertex coordinates.

• getTokenInfoMapFromPath(from, rpcUrl, path) – fetches token metadata for all tokens/wrappers in a path; feed into other helpers.

• getWrappedTokensFromPath(path, tokenInfoMap) – list wrapped tokens present in the path.

• getExpectedUnwrappedTokenTotals(path, tokenInfoMap) – estimate ERC1155 amounts recovered after unwrapping wrappers used in the path.

• replaceWrappedTokensWithAvatars(path, tokenInfoMap) – rewrite path legs to underlying avatar addresses (for ERC1155 semantics).

• replaceWrappedTokens(path, unwrappedMap) – replace wrapped token addresses using a precomputed mapping.

• shrinkPathValues(path, sink, retainBps) – scale down flows proportionally (e.g., execute only 70% of a path).

• assertNoNettedFlowMismatch(path) – throw if transfers do not net to zero (consistency check).

• computeNettedFlow(path) – derive net inflow/outflow per address for diagnostics.

Error handling & tips

• maxFlow === 0: check mutual trust or unwrap static/demurraged balances back to ERC1155.

• Paths needing wrapped balances will fail unless useWrappedBalances is true.