Web3 Provider Watch — 2026-09-19

To claim. The Arbitrum Open House Singapore buildathon closes Oct 4, not the ~Oct 2 this watch had carried from a third-party countdown — two extra days, read this run from openhouse.arbitrum.io. Registration is open and free; submit before Oct 4 for a share of $115K, part of $415K across both phases, all USDC, paid against agreed milestones. Subscan's pricing page became readable for the first time and carries a standing 20% discount for annual payment (Developer $182, Advanced $1,910, Professional $3,830); it never says whether those figures are monthly or annual, so confirm with api@subscan.io first. Nansen's 2x-credit window still closes Sept 27.

New services. The Solana Explorer now runs an official MCP server at explorer.solana.com/mcp — open, no key, no signup, across mainnet-beta, devnet and testnet. Both tools are read-only; inspect_entity takes one base58 address or signature and returns the explorer's own IDL decoding as JSON. No rate limit is published, so a metered provider still belongs behind it. Solana Tracker added liquidity events to all four token trade endpoints (events=all|trades|liquidity), five Datastream liquidity room scopes and enrich=identity labels; existing defaults are unchanged. Hexens launched Glider Monitor, continuous post-audit contract monitoring on major EVM chains: free Community tier, paid from $180/mo.

Act by date. First, and undated: Agave v4.3.0 reached mainnet Sept 18 and now errors on base58-encoded version-1 transactions where earlier releases returned a silently wrong result. Before it holds a supermajority, move sendTransaction and simulateTransaction to base64, add maxSupportedTransactionVersion: 1 and base64 to every getBlock and getTransaction, and bump yellowstone-grpc-client to 13.2.0+ with proto 12.4.0+. Then: Alchemy's EIP-7702 default changes Sept 21 and nine NFT endpoints sunset Sept 30. Helicon activates Sept 22 at 15:00 UTC on AvalancheGo v1.15.0 — C-Chain state sync is unsupported around activation, and a new Firewood node must set state-sync-enabled=false or exit FATAL. Moralis drops Moonbeam, Moonriver and Lisk Sept 25. Sui's archival JSON-RPC fallback disconnects at end of September, code removal mid-October. Oct 1 carries two QuickNode changes: Solana gRPC metering rises to 15 credits per 0.1 MB and legacy port 10000 sunsets. Port 443 meters compressed bytes, recovering part of the rise, but Basic Auth fails there.

Changes. The Graph Market's pricing renders at last: Scaling $100/mo (155M processed blocks, 500 GiB egress), Pro $500/mo (400M, 2 TiB), free hard-capped at 7M blocks and 5 GiB with no overage purchasable. Space and Time documents 30 free Studio queries a month, previously unpublished. PublicNode's key-free endpoint count moved 74 to 77. Alchemy's free-tier throughput conflict resolves as a real disagreement between two live pages; the documented 300 CU/s is the safer figure.

Gaps. ETHGlobal Tokyo could not be re-verified — its event page returned HTTP 500 twice. Solscan's billing-cycle discounts and Space and Time's $200 cap stay unverified behind client-rendered or missing pages; Reservoir's homepage refused three times. Arc mainnet launched Sept 16, one day before this window, so day-one posts from ten providers fall outside it. Helius, Syndica, Triton One, Pinax and Infura publish no changelog.