Chain specs

Smart Router is chain-agnostic. It has no chain logic baked in — every chain it serves is described by a JSON spec. The spec is what teaches the router how to talk to a chain: which RPC methods exist, how to parse each one, where finality sits, and which capabilities (archive, debug, …) a node must have to serve a given method.

This is why adding a chain never means a code change or a new build — it's just another spec file the router loads at startup.

What a spec defines

Part	What it's for
API methods	Every RPC method the chain exposes, per interface (jsonrpc / rest / grpc / tendermintrpc).
Parser rules	How to read a method's request/response — e.g. which param holds the block number — so the router can cache, route, and apply consistency correctly.
Categories	Per-method flags: read vs. write (stateful), whether it's cacheable, which addon/extension it needs (archive, debug). These drive node selection and caching.
Finality parameters	Block times and finalization distance — feed the integrity lag gate and finalized-vs-not cache TTLs.
Imports	A spec can import another (e.g. Arbitrum imports ETH1), inheriting its methods and addons. The router resolves imports transitively.

How specs are loaded

Pass a spec source at startup with --use-static-spec (repeatable; later sources override earlier ones for the same chain id):

# a local directory
smartrouter config.yml --use-static-spec specs/

# or straight from a GitHub/GitLab repo — no manual copy
smartrouter config.yml \
  --use-static-spec https://github.com/Magma-Devs/lava-specs/tree/main

The same value backs the Docker SR_SPEC env var. The built-in spec fetcher pulls specs from a remote URL at boot and caches them, so a chain that isn't in the bundled specs/ still resolves when you point at the catalog.

Where specs come from

Source	What's in it	Use when
Bundled — specs/ in the repo	A handful of production chains + reusable Cosmos building blocks (what the example configs use)	quickest start; what the init_smartrouter_* scripts use
Catalog — Magma-Devs/lava-specs	The full set spanning every major ecosystem, kept up to date	production deployments serving any chain beyond the bundled ones

Building blocks

Some specs describe no chain of their own — they exist purely to be imported by chain specs that share an API surface. The router never serves these directly.

Spec	Role
cosmossdk.json	base Cosmos SDK surface
cosmossdk_full.json	Cosmos chains needing extended methods
cosmossdkv45.json	older Cosmos SDK v0.45 chains
cosmossdkv50.json	newer Cosmos SDK v0.50 chains
cosmoswasm.json	CosmWasm-enabled chains
tendermint.json	every Tendermint-based chain
ibc.json	every IBC-capable chain
ethermint.json	EVM-on-Cosmos base, imported by Evmos

Need a chain that isn't listed?

The catalog is maintained by Magma. If the chain you need isn't there, open an issue with the chain, the API interface (JSON-RPC / REST / gRPC / Tendermint RPC), and one or two reference upstream nodes, and we'll add it.