FluxRPC: lean Solana RPC and open transaction sender

FluxRPC is two related surfaces for Solana builders:

1. A hosted RPC product at fluxrpc.com (Solana and Fogo), positioned as high-performance JSON-RPC with Yellowstone gRPC on paid plans and transparent pricing (no credit bundles).
2. Open-source landing helpers under github.com/fluxrpc— notably transaction_sender (Go) and an experimental transaction_sender_js (WebTransport to TPU).

Founder: Scott (@CloakdDev), also noted in our RPC providers comparison as a Breakout hackathon winner building for load resilience and low latency.

Click to zoom

People and links

Hosted RPC (product)

Marketing claims to validate on your workload (not on a landing page):

• JSON-RPC for Solana (and Fogo)
• Yellowstone gRPC streaming on paid plans
• Emphasis on head-slot freshness vs lagged shared pools
• Pricing without credit packs for “features you never touch”

Builder checklist before you switch production traffic:

1. Measure getSlot / account subscribe lag vs your current provider under your peak QPS.
2. If you use Geyser: reconnect behaviour, filter drop rate, and auth token rotation on Flux endpoints.
3. Transaction landing: staked connections and dual-route (RPC + Jito) still matter — see Jito bundles and priority fees.
4. Confirm archival / historical method coverage for your indexer.

# Drop-in RPC URL shape (use your real endpoint + key from the dashboard)
export SOLANA_RPC_URL="https://<your-fluxrpc-host>"
solana cluster-version --url "$SOLANA_RPC_URL"

Open source: transaction_sender

fluxrpc/transaction_sender is a Go service that accepts already-serialized transactions and forwards them to SVM leaders (Solana / Fogo) with leader tracking. Sends use both QUIC and UDP toward the leader processing the N+1 slot.

Upstream guidance: for most non-spam flows under the SWQoS threshold, self-hosting this path can replace a “send-only” dependency on a heavy hosted RPC — you still need RPC + WebSocket for schedule and slot feeds.

Run the sender

# Env
export HTTP_PORT=8080
export RPC_URL="https://your-rpc.example"
export WS_URL="wss://your-rpc.example"

# Dev
go run ./runtime/main.go --rpc_url "$RPC_URL"

# Static Linux build (from upstream README pattern)
GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build \
  -ldflags='-s -w -extldflags "-static"' \
  -o transaction_sender ./runtime/main.go

# Or Docker via repo Dockerfile — hit the exposed HTTP port from your app

Flags mirror env: http_port, rpc_url, ws_url. Your app still signs locally; this process is a forwarder, not a remote signer.

JS / WebTransport variant

transaction_sender_js targets WebTransport dispatch straight toward the TPU. Marked early (v0.001-class); treat as experimental next to the Go service.

base58 helper

fluxrpc/base58 — optimized Base58 encode/decode for Go (small supporting library).

When to pick FluxRPC

Related on DevRels

• Solana RPC providers comparison
• Yellowstone gRPC / Geyser
• Jito bundles

Summary

FluxRPC (github.com/fluxrpc) is Scott / @CloakdDev’s lean Solana RPC shop plus open tools for leader-aware transaction forwarding. Use the hosted API when you want simple endpoints and gRPC without credit gymnastics; run transaction_sender when you want QUIC/UDP delivery to N+1 leaders under your own process — still paired with a real RPC/WS and honest landing tests during congestion.