How do I mock the Helius Solana RPC + Enhanced API locally?

Install stunt, add a one-service block to stunt.yaml (adapter: embedded:helius-style), and run stunt up. You get a local, stateful stand-in for Helius Solana RPC + Enhanced API v0 — 11 routes over rest — with no remote account, no network, and no bills.

Is the Helius Solana RPC + Enhanced API mock data synthetic?

Yes — entirely. The adapter returns generated data only; stunt's adapter lint rejects real-looking secrets and PII at build time. It simulates the shape and behavior of Helius Solana RPC + Enhanced API (routes, status codes, pagination, webhooks), never real records.

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helius-style

simulates Helius Solana RPC + Enhanced API v0

restadapter v0.1.011 routes

verification

VMVM tier — no SDK suite yet· surface 11 · not implemented 3 · differs 6

use it

# add to stunt.yaml
services:
  helius:
    adapter: embedded:helius-style

# then
$ stunt up

The embedded: source extracts this adapter from the binary — no git clone, fully offline.

how to mock the Helius Solana RPC + Enhanced API locally

Install stunt, paste the service block above into stunt.yaml, run stunt up — then point your client at localhost instead of Helius Solana RPC + Enhanced API. It works offline, keeps state across requests and restarts, and every response is synthetic: the route shapes, status codes, pagination, and webhook delivery follow the real Helius Solana RPC + Enhanced API v0 surface — the data is fake, the behavior is real.

api surface (11)

generated from the adapter manifest — exactly what boots, nothing more

11 routes

POST/

POST/v0/transactions

GET/v0/addresses/{address}/transactions

GET/v0/addresses/{address}/balances

GET/v0/addresses/{address}/nfts

POST/v0/names

POST/v0/webhooks

GET/v0/webhooks

GET/v0/webhooks/{webhookId}

PUT/v0/webhooks/{webhookId}

DELETE/v0/webhooks/{webhookId}

VM-verified behaviors (10)

✓the api-key query gate rejects both surfaces
✓the JSON-RPC reads answer deterministic values; an unknown method is a -32601 envelope
✓sendTransaction walks null → processed → confirmed → finalized, firing the enhanced webhook exactly once at first confirmation
✓simulate_fail lands an on-chain InstructionError while confirmation still proceeds
✓the enhanced history seeds once per address, newest first, in the Helius parsed shape
✓type/source filters and before/until/limit paging narrow the history
✓a sent transaction joins its address's history; other addresses do not see it
✓the parse-transactions contract holds and the balances/nfts/names lookups are deterministic
✓webhook registration round-trips the Helius config shape with 404s for unknown ids
✓deliveries are unsigned, carry authHeader as Authorization, honor transactionTypes and fire exactly once

Not implemented (3)

RPC covers 6 methods; no getAccountInfo, getSlot, getSignaturesForAddress
No DAS API (getAsset, searchAssets) or /v0/tokens metadata endpoints
No getPriorityFeeEstimate, requestAirdrop, or WebSocket subscriptions

Differs from the real API (6)

Webhook payloads carry one transaction each; real Helius batches an array
Confirmation milestones fixed by clock: processed 1-2s, confirmed 2-3s, final 3s+
sendTransaction config takes simulate_fail/simulate_type/simulate_address
Enhanced transactions limit capped at 100 (real API max 1000)
A crossed before/until cursor pair silently ignores the until signature
The confirmation webhook fires only when a read lands inside the 2-3s confirmed window

full scorecard →

want more of the Helius Solana RPC + Enhanced API surface? adapters are YAML + Starlark — the authoring guide covers adding routes, fixtures, and state machines. Open an issue for anything big first, or just file a PR — merged routes ship in the next release.