Union RPC endpoints: free public URLs by latency
HTTP round-trip latency for Tendermint /status queries against every available public Union (union-1) endpoint, audited every 60 seconds from 3 regions.
TL;DR. As of , Nodes.Guru has the lowest median latency of the 2 free public Union RPC endpoints measured, 99 ms (p50, 24h, 3 regions). Source: OpenChainBench, https://openchainbench.com/benchmarks/union-rpc. 2 public endpoints, no key: rpc-1.union.nodes.guru, union-rpc.stakeandrelax.net. Full URLs with their 24h median are listed below.
Companion page
Comparing free RPC endpoints across every chain we measure? Open the cross-chain RPC matrix →
Union is a trust-minimised, zero-knowledge cross-chain protocol built on a custom Cosmos SDK chain (chain ID union-1). It enables secure interoperability between Cosmos, EVM, and other ecosystems via ZK proof-based consensus verification, with no external validators or multisigs required. The chain uses the standard Tendermint RPC interface; block height is fetched via the /status endpoint. Public keyless RPC nodes are provided by Nodes.Guru, Stake And Relax, and High Stakes. Every provider was live-verified with consecutive block-height probes at launch.
Methodology
Union: 2 free public RPC endpoints answering `GET /status` every 60 seconds from us-east, eu-west and Singapore, ranked by 24h median. Nodes.Guru leads at 99 ms. We measure the round-trip latency of a Tendermint /status query against every available public Union endpoint that sustains continuous probing: 2 providers live today, every 60 seconds, from us-east, eu-west and Singapore. Each provider is probed via a GET /status request from which the block number is extracted. The harness classifies every response (ok / http_err / jsonrpc_err / stale / timeout) with a Cosmos-scaled staleness gap (20 blocks, around 80 s at 4 s/block). The cross-chain view lives on the parent rpc-capabilities benchmark; this page is the Union-scoped answer with per-region breakdowns as a first-class dimension.
Results: 2 free public Union RPC endpoints ranked by p50 latency (24h, 3 regions)
| № | Providers | p50 | p90 | p99 | Success |
|---|---|---|---|---|---|
| 1 | Nodes.Guru | 99 ms | 116 ms | 194 ms | 100.00% |
| 2 | Stake And Relax | 113 ms | 146 ms | 353 ms | 100.00% |
Public Union RPC endpoints measured
The 2 no-key endpoints answering our probes today, with their current 24h median. Paste one into a wallet or a client as is: no signup, no key. Private providers (API key) are never listed with a URL.
Nodes.Guruhttps://rpc-1.union.nodes.guru99 ms100.0%
Stake And Relaxhttps://union-rpc.stakeandrelax.net113 ms100.0%
Median round-trip and success rate over the last 24 hours across the probe regions; the ranked table above carries p90, p99 and the per-region split.
Frequently asked
Which Union RPC endpoints work without an API key?
3 endpoints are probed on this chain: Nodes.Guru (rpc-1.union.nodes.guru), Stake And Relax (union-rpc.stakeandrelax.net), and High Stakes (union-rpc.highstakes.ch). Every listed endpoint was live-verified before inclusion.
What is Union and why does its RPC latency matter?
Union is a ZK-based cross-chain interoperability protocol with a native Cosmos SDK chain (union-1). It connects blockchains without widely used intermediaries by verifying consensus proofs on-chain. Developers building cross-chain applications, bridges, or omnichain protocols on Union need reliable low-latency RPC access to query transactions, proofs, and chain state.
What makes Union different from other cross-chain protocols?
Union replaces widely used validator sets and multisigs with ZK consensus proofs, making cross-chain message passing verifiable on-chain. This means no external trust assumptions: the security of the bridge reduces to the security of the underlying chains and ZK proof system.
Source code github.com/ChainBench/OpenChainBench/tree/main/harnesses/rpc-capabilities