Chains API

A Node.js API query service built with Fastify that indexes and provides access to blockchain chain data from multiple sources. Also available as an MCP (Model Context Protocol) server for AI assistants.

Code Quality & Testing

This project maintains high code quality standards through:

• Comprehensive Testing: Includes unit tests, integration tests, and fuzz testing

  • 300+ test cases covering all core functionality

  • Continuous integration with automated test runs on every push

  • See Testing Documentation for details

• SonarQube Analysis: Automated code quality scanning on every commit

  • Enforces code coverage requirements (≥80%)

  • Monitors code duplication (≤3%)

  • Tracks cognitive complexity and code smells

All changes are validated through GitHub Actions CI/CD pipeline, ensuring code quality and test coverage before deployment.

Related MCP server: Flow MCP Server

Features

• Multi-Source Data Aggregation: Combines data from multiple blockchain registries:

  • The Graph Networks Registry

  • Chainlist RPCs

  • Chain ID Network (for basic chain data and L2 relation indexing using parent field)

  • SLIP-0044 Coin Types

• Fast API: Built with Fastify for high performance

• MCP Server: Available as a Model Context Protocol server for AI assistants

• Indexed Data: Efficient querying with indexed chain data

• Search Capabilities: Search chains by name, ID, or other attributes

• RESTful Endpoints: Clean and intuitive API design

• Chain Relations & Tags: Automatic indexing of chain relationships and tags

  • Tags: Testnet, L2, Beacon

  • Relations: testnetOf, mainnetOf, l2Of, parentOf, beaconOf with resolved chain IDs

  • Example: Base Sepolia (84532) is tagged as Testnet and L2, with relations to Base (8453) and Sepolia (11155111)

  • Reverse relations: Mainnets have mainnetOf relations pointing to testnets, L1s have parentOf relations pointing to L2s

• RPC Health Monitoring: Automatic background monitoring of RPC endpoints to identify working and failed nodes.

• Data Validation: Built-in validation tools to identify data inconsistencies between multiple sources (e.g., The Graph registry vs. Chainlist).

Installation

Using npm

npm install

Using Docker

Pull from GitHub Container Registry

Pre-built Docker images are automatically published to GitHub Container Registry (GHCR) on every push to the main branch:

# Pull the latest image
docker pull ghcr.io/johnaverse/chains-api:latest

# Or pull a specific version
docker pull ghcr.io/johnaverse/chains-api:v1.1.1

Build Docker image locally

# Build the image
docker build -t chains-api .

# Or using docker compose
docker compose build

Usage

Running with Docker

Run the REST API server

# Using pre-built image from GHCR
docker run -d -p 3000:3000 --name chains-api ghcr.io/johnaverse/chains-api:latest

# Or using locally built image
docker run -d -p 3000:3000 --name chains-api chains-api

# With custom environment variables
docker run -d -p 3000:3000 \
  -e PORT=3000 \
  -e HOST=0.0.0.0 \
  --name chains-api \
  ghcr.io/johnaverse/chains-api:latest

The API will be available at http://localhost:3000.

Run the MCP HTTP server

docker run -d -p 3001:3001 \
  --name chains-api-mcp \
  ghcr.io/johnaverse/chains-api:latest \
  node mcp-server-http.js

The MCP HTTP server will be available at http://localhost:3001.

Using Docker Compose

A docker-compose.yml file is included in the repository that runs both the REST API server on port 3000 and the MCP HTTP server on port 3001:

docker compose up -d

To use pre-built images from GHCR instead of building locally, modify the docker-compose.yml to use image: ghcr.io/johnaverse/chains-api:latest instead of build: .

The default configuration:

services:
  chains-api:
    build: .
    image: chains-api:latest
    container_name: chains-api
    ports:
      - "3000:3000"
    environment:
      - PORT=3000
      - HOST=0.0.0.0
    restart: unless-stopped
    healthcheck:
      test:
        [
          "CMD",
          "node",
          "-e",
          "require('http').get('http://localhost:3000/health', (r) => { process.exit(r.statusCode === 200 ? 0 : 1) })",
        ]
      interval: 30s
      timeout: 10s
      retries: 3
      start_period: 5s

  chains-api-mcp:
    build: .
    image: chains-api:latest
    container_name: chains-api-mcp
    command: node mcp-server-http.js
    ports:
      - "3001:3001"
    environment:
      - MCP_PORT=3001
      - MCP_HOST=0.0.0.0
    restart: unless-stopped
    healthcheck:
      test:
        [
          "CMD",
          "node",
          "-e",
          "require('http').get('http://localhost:3001/health', (r) => { process.exit(r.statusCode === 200 ? 0 : 1) })",
        ]
      interval: 30s
      timeout: 10s
      retries: 3
      start_period: 5s

Running with npm

REST API Server

Start the server

npm start

The server will start on http://localhost:3000 by default.

Development mode (with auto-reload)

npm run dev

Using a Proxy (Optional)

To route all outbound requests through a proxy server, set the PROXY_URL environment variable:

# Using a proxy without authentication
PROXY_URL=http://proxy.example.com:8080 npm start

# Using a proxy with authentication
PROXY_URL=http://user:pass@proxy.example.com:8080 npm start

When configured, the proxy will be used for:

• All RPC endpoint health checks and monitoring

• Fetching data from external sources (The Graph, Chainlist, etc.)

The proxy configuration is optional and disabled by default. See the Environment Variables section for more details.

MCP Server (for AI Assistants)

The Chains API can also be used as an MCP (Model Context Protocol) server, allowing AI assistants like Claude to query blockchain chain data directly. Two transport modes are supported:

1. Stdio Mode (for local AI assistants like Claude Desktop)

2. HTTP Mode (for external clients like n8n, Make.com, etc.)

Running the MCP Server (Stdio Mode)

For local use with Claude Desktop and similar applications:

npm run mcp

Or directly with Node.js:

node mcp-server.js

Running the MCP HTTP Server (Network Mode)

For external clients that need HTTP access:

npm run mcp:http

Or directly with Node.js:

node mcp-server-http.js

The HTTP server will start on http://0.0.0.0:3001 by default (configurable via MCP_PORT and MCP_HOST environment variables).

Endpoints:

• POST /mcp - MCP protocol endpoint for tool calls

• DELETE /mcp - Session termination endpoint

• GET /health - Health check

• GET / - Server information

Example HTTP MCP usage with curl:

# Initialize a session
curl -X POST http://localhost:3001/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"my-client","version":"1.1.1"}}}'

# Extract session ID from the mcp-session-id header, then call a tool:
curl -X POST http://localhost:3001/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -H "mcp-session-id: <session-id>" \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"get_chain_by_id","arguments":{"chainId":1}}}'

MCP Server Configuration (Stdio Mode)

To use the Chains API MCP server with Claude Desktop or other MCP clients, add it to your MCP settings configuration file:

For Claude Desktop (~/Library/Application Support/Claude/claude_desktop_config.json on macOS):

{
  "mcpServers": {
    "chains-api": {
      "command": "node",
      "args": ["/path/to/chains-api/mcp-server.js"]
    }
  }
}

Or if you've installed the package globally:

{
  "mcpServers": {
    "chains-api": {
      "command": "chains-api-mcp"
    }
  }
}

Available MCP Tools

The MCP server provides the following tools for querying blockchain chain data:

• get_chains: Get all blockchain chains, optionally filtered by tag (Testnet, L2, or Beacon)

• get_chain_by_id: Get detailed information about a specific blockchain chain by its chain ID (with its research block, minus the hardware profiles and with at most 12 compact channels (one per platform before any repeats) plus channelsTotal and channelsByPlatform; dated compact availability observations with channelsAvailabilityNote retain closure/unknown states and cache caveats; hasNodeRequirements says whether to call the next tool)

• get_node_requirements: Documented hardware/system requirements for running a node on a chain, from the node hardware research — one profile per role (full_node, validator, archive, rpc, …) × tier (minimum / recommended / example) × client, most specific first, optional role / level filters and a limit (default 8). Role filtering also includes explicitly sourced prerequisiteFor links: Nibiru validator lookups include its full-node prerequisite under the original full_node role, counted once. The link's sizing: "not_established" does not claim dedicated validator hardware. Requirements come back as strings in the publisher's original units ("memory capacity: 16 GB") and are never converted. Also carries software: the node/client repositories the research tied to the chain (with kind and status) and observedClients, the client software and versions seen on the chain's live RPC endpoints (evidence of what operators run, not a requirement). Compact JSON on purpose: the dashboard assistant caps tool results at ASSISTANT_TOOL_RESULT_MAX_CHARS

• search_chains: Search for blockchain chains by name or other attributes

• get_endpoints: Get RPC, firehose, and substreams endpoints for a specific chain or all chains

• get_client_releases: Recent node/client software releases from chains-client-feed (via CLIENT_FEED_URL), newest first — version/tag, prerelease, mandatory, the AI summary and any hard fork the notes announce (fork: name, network, activationAt/Block/Epoch/Slot, state). Filters: client (resolved to its registry repositories), repo (owner/repo or github: / gitlab: prefixed), chainId, fork, since / until (inclusive ISO dates; a bare until covers that day); capped (default 15, max 50) with totalMatched / truncated

• get_network_clients: Client repositories known to serve a chain, each with the kinds it plays there, networkCount, latest release, latest fork and a compact development activity (chains-client-feed's client → networks index)

• get_client_activity: How actively a client is developed (default-branch commits and merged PRs in 30/90 days), its open issues and PRs, open issues labeled bug or critical/security, published GitHub security advisories, and an activity and attention level with reasons — by repo or by client name (refreshed daily by chains-client-feed; GitHub needs the feed's GITHUB_TOKEN)

• get_relations: Get chain relationships (testnet/mainnet, L2/L1, etc.) for a specific chain or all chains

• get_slip44: Get SLIP-0044 coin type information by coin type ID or all coin types

Each tool returns JSON data that can be used by AI assistants to answer questions about blockchain networks.

Environment Variables

Server Configuration

• PORT: REST API server port (default: 3000)

• HOST: REST API server host (default: 0.0.0.0)

• MCP_PORT: MCP HTTP server port (default: 3001)

• MCP_HOST: MCP HTTP server host (default: 0.0.0.0)

Proxy Configuration (Optional)

• PROXY_URL: HTTP/HTTPS proxy URL for all outbound requests (default: empty/disabled)

  • Example: http://proxy.example.com:8080

  • With authentication: http://user:pass@proxy.example.com:8080

  • When set, all RPC requests and data source fetching will route through this proxy

  • Leave empty or unset to disable proxy support

Rate Limiting

• RATE_LIMIT_MAX: Maximum requests per window for global endpoints (default: 100)

• RATE_LIMIT_WINDOW_MS: Rate limit window in milliseconds (default: 60000 = 1 minute)

• RELOAD_RATE_LIMIT_MAX: Maximum /reload requests per window (default: 5)

• SEARCH_RATE_LIMIT_MAX: Maximum /search requests per window (default: 30)

RPC Health Check

• RPC_CHECK_TIMEOUT_MS: Timeout per RPC health check call in milliseconds (default: 8000)

• RPC_CHECK_CONCURRENCY: Number of parallel RPC health checks (default: 8)

• MAX_ENDPOINTS_PER_CHAIN: Maximum RPC endpoints tested per chain (default: 5)

Data Cache

• DATA_CACHE_ENABLED: Enable disk-backed startup cache (default: true)

• DATA_CACHE_FILE: Snapshot file path used for stale-first startup (default: .cache/chains-api-data.json)

Assistant (Optional)

An LLM chat assistant over the whole registry plus live incidents, exposed at POST /assistant/chat and consumed by the dashboard's floating chat overlay (corner button, available on every view). It runs a tool-use loop against any OpenAI-compatible server (Ollama, vLLM, LM Studio) and stays disabled until configured:

ollama pull qwen3
ASSISTANT_LLM_URL=http://localhost:11434 npm start

• ASSISTANT_LLM_URL: OpenAI-compatible LLM base URL (default: empty = assistant disabled)

• ASSISTANT_LLM_API_KEY: Bearer token for key-protected servers such as OpenAI or OpenRouter (default: empty — not needed for a plain Ollama)

• ASSISTANT_MODEL: Model name passed to /v1/chat/completions (default: qwen3)

• ASSISTANT_MAX_TOOL_ITERATIONS: Hard cap on LLM round-trips per request (default: 6)

• ASSISTANT_TIMEOUT_MS: Overall per-request deadline (default: 60000)

• ASSISTANT_MAX_TOKENS: max_tokens per LLM call (default: 1024)

• ASSISTANT_RATE_LIMIT_MAX: Maximum /assistant/chat requests per window per IP (default: 10)

• ASSISTANT_TOPIC_GUARD: Pre-classify each question with a cheap extra LLM call and refuse off-topic ones before the tool loop runs; fails open if the classifier misbehaves (default: true)

• ASSISTANT_FALLBACK_LLM_URL / ASSISTANT_FALLBACK_MODEL / ASSISTANT_FALLBACK_LLM_API_KEY: Optional backup provider — see below.

Fallback provider (optional)

Configure a second OpenAI-compatible server and the assistant survives the primary going down:

# Example 1: big model with a smaller local backup on another port
ASSISTANT_LLM_URL=http://10.0.0.47:8000        ASSISTANT_MODEL=qwen3-27b \
ASSISTANT_FALLBACK_LLM_URL=http://localhost:11434 ASSISTANT_FALLBACK_MODEL=qwen3:8b \
npm start

# Example 2: local primary with a hosted API as the backup
ASSISTANT_LLM_URL=http://localhost:11434       ASSISTANT_MODEL=qwen3 \
ASSISTANT_FALLBACK_LLM_URL=https://openrouter.ai/api ASSISTANT_FALLBACK_MODEL=qwen/qwen3-32b \
ASSISTANT_FALLBACK_LLM_API_KEY=sk-or-... \
npm start

Behavior:

• A chat run starts on the primary; if any LLM call fails (connection refused, timeout, HTTP error), the run switches to the backup and stays on it for the rest of that run. The next chat tries the primary again — no manual reset needed after recovery.

• The switch is visible: the thinking trace shows a "switching to backup model" step, the answer JSON carries viaFallback: true, and the dashboard bubble gets a backup model badge.

• While an untried backup remains, a single primary attempt is capped at 60s so an unresponsive primary can't consume the whole request budget before failover.

• GET /assistant reports reachable: true if either provider answers, so the dashboard pill stays green during a primary outage.

• The backup must handle tool/function calling for full functionality; if it's a weaker model, expect simpler answers rather than failures — all the harness defenses (arg validation, iteration caps) apply to it too.

• ASSISTANT_FALLBACK_MODEL defaults to ASSISTANT_MODEL when unset, and the key is only needed for auth-protected backups.

• LIVE_INCIDENTS_URL: Live incident feed for the get_live_incidents tool (default: https://chains-status-news.johnaverse.cc)

• FORUM_NEWS_URL: Forum/governance news feed for the get_forum_news tool (default: https://chains-forum-news.johnaverse.cc)

• GET /upgrades?chainId=&network=&limit=: cross-feed upgrade timeline — scheduled upgrades/maintenance with required software ([{client, version}]), urgency, activation time, incidents that followed on the same network within 24h (suspectedCause: "upgrade" — temporal correlation, not asserted causation), and related forum/news context. network accepts a name for chains with no EVM chain ID ("Solana", "Canton"). Also exposed as the get_chain_upgrades MCP tool.

• GET /forks?chainId=&phase=&scheduledOnly=&include=&limit=: forks as ENTITIES — one entry per fork per network, grouped across all three feeds (status pages and provider windows from chains-status-news, governance/research posts from chains-forum-news, articles from chains-news, and — when CLIENT_FEED_URL is set — client release notes and changelogs from chains-client-feed, each fetched with ?fork=true; a release attributed only to its repository's networks, with three or more of them and none named in the notes, is left unscoped rather than filed under each), so a fork that six providers, a forum thread and the project blog announced appears once. Grouping is by codename ("Glamsterdam" = "the Glamsterdam upgrade"), else activation height, else exact stated instant; unnamed notices on one network within six hours of each other — every one within 6h of the cluster's earliest time, so a run of notices cannot chain into a day-long fork — (or at the same height) are one fork, and fold into the named fork on that network at the same activation. The network's own sources and primary outlets outrank provider windows, which outrank secondary news, when they disagree on the date — except that newer status, forum or primary sources moving the date by more than a day count as a reschedule. When a source names the forking network (fork.network), the fork is filed under that network's chains, not the poster's: an Arbitrum post about Ethereum's fork is a chain 1 fork, and its date ranks as indirect (like secondary news), not as Ethereum's own. A test-network fork never inherits the mainnet chain of a post that only names the mainnet. A name made only of generic words ("Network Upgrade") is treated as unnamed. A named mention with no network at all folds into the single network-scoped fork of that name; groups made of exactly the same events (one window naming three networks) are one entry listing every network in networks; each fork's events are de-duplicated by URL. Only real forks are listed by default (kind: "fork"): a group counts as a fork when any member is classed planned_hard_fork (or legacy hard_fork), when no member carries a class at all, when it activates at a block height, or when it has a real name (not generic, not a version number like v29.0.1) AND a stated activation; every other marked group — client releases, RPC patches, provider infrastructure work classed planned_software_update — is kind: "upgrade", listed only with include=upgrades, and byKind counts both. A stated activation more than 30 days before the post that states it is dropped as implausible (the classifier guessing a year) unless the fork is completed; the dropped value stays visible as the event's implausibleActivationAt. A claim's time for "newest wins" is the enrichment's createdAt, else publishedAt (never updatedAt, which some providers set to the future window start), capped at now. A date-only activation is activationPrecision: "day" and stays upcoming until that UTC day ends; state: completed is always past. chains-news' enrichment.forks (several activations in one post) is read as one mention per entry. Each fork lists feeds and its events with each source's claimed activationAt; the response's top-level feeds says which feeds answered this round (ok), and stale: true marks a feed whose forks are left over from an earlier fetch; filtered says whether the feed honoured ?fork=true (a 400 is remembered for an hour, so the filtered request is not retried on every refresh) and oldest is the oldest item in the page read — when unfiltered, forks announced before it are not visible. Carries activationAt with activationEvidence (stated / observed from a reached block height / estimated from a future one — approximate, not a schedule), activationBlock, state, lifecycle phase (upcoming/past/cancelled/unscheduled) and sources. scheduledOnly=true for a calendar view; byPhase counts cover everything matched, not just the page. Also exposed as the get_forks MCP tool.

• CLIENT_FEED_URL: Blockchain client release feed (chains-client-feed), read by /forks / get_forks, the /client-releases proxy routes and the get_client_releases / get_network_clients tools (default: unset = not read, and the proxy answers 503; there is no public host). CLIENT_FEED_FETCH_TIMEOUT_MS (default 10000), CLIENT_FEED_CACHE_TTL_MS (default 60000: how long the proxy holds one upstream answer; the last good answer is served, with stale: true, while the feed is down).

• GET /repositories: per chain, the research's node/client repositories and the hardware research's client names and evidence links — the raw input chains-client-feed builds its client registry and client → networks index from.

• WEB3_NEWS_URL: Ecosystem/editorial news feed for the get_web3_news tool (default: https://chains-news.johnaverse.cc). In-cluster deployments should set this to the Service DNS name.

• WEB3_NEWS_CACHE_TTL_MS / WEB3_NEWS_FETCH_TIMEOUT_MS: cache window and per-request timeout for that feed (defaults 60000 / 10000)

Other

• BODY_LIMIT: Maximum request body size in bytes (default: 1048576 = 1 MB)

• MAX_PARAM_LENGTH: Maximum URL parameter length (default: 200)

• MAX_SEARCH_QUERY_LENGTH: Maximum search query length (default: 200)

• CORS_ORIGIN: Allowed CORS origins (default: * for all origins)

See .env.example for a complete list of environment variables with example values.

API Endpoints

GET /

Get API information and available endpoints.

Response:

{
  "name": "Chains API",
  "version": "1.1.1",
  "description": "API query service for blockchain chain data from multiple sources",
  "endpoints": { ... },
  "dataSources": [ ... ]
}

GET /health

Health check and data status.

Response:

{
  "status": "ok",
  "dataLoaded": true,
  "lastUpdated": "2026-02-07T14:13:42.104Z",
  "totalChains": 1234
}

GET /assistant

Assistant availability probe: {"enabled": true, "model": "qwen3"} (enabled: false when no LLM is configured).

POST /assistant/chat

Chat with the assistant. Stateless — send the full conversation each turn; the assistant may reply with a clarifying question (e.g. mainnet vs testnet) that you answer in a follow-up message.

Fast answers return 200 with the result directly. Runs that outlive the sync window (ASSISTANT_SYNC_WAIT_MS, default 8s — typical for large local models) return 202 {"jobId", "status": "running", "pollAfterMs"}; poll GET /assistant/chat/:jobId until status is done (result fields included) or error. This keeps every HTTP request short, so reverse-proxy/CDN timeouts never kill a slow LLM run.

Request:

{
  "messages": [{ "role": "user", "content": "is base healthy right now?" }],
  "context": { "view": "networks", "chainId": 8453 }
}

Response:

{
  "reply": "Base mainnet (`8453`): 5/5 monitored RPC endpoints healthy…",
  "toolCalls": [{ "name": "get_rpc_monitor_by_id", "args": { "chainId": 8453 } }],
  "degraded": false,
  "usage": { "promptTokens": 1874, "completionTokens": 96 }
}

Errors: 503 when not configured or the LLM is unreachable, 429 on rate limit, 400 on invalid payloads.

GET /rpc-monitor

Get RPC endpoint monitoring results for all chains. At startup, a background process validates the health of the indexed RPC endpoints.

Response:

{
  "isMonitoring": false,
  "lastUpdated": "2026-02-07T14:13:42.104Z",
  "totalEndpoints": 4236,
  "testedEndpoints": 850,
  "workingEndpoints": 782,
  "results": [
    {
      "chainId": 1,
      "chainName": "Ethereum Mainnet",
      "url": "https://eth.rpc.pinax.network",
      "status": "working",
      "clientVersion": "geth/v1.14.0",
      "blockNumber": 19123456,
      "testedAt": "2026-02-07T14:13:42.104Z"
    },
    ...
  ]
}

GET /rpc-monitor/:id

Get RPC monitoring results for a specific chain by its chain ID.

Example: GET /rpc-monitor/1 (Ethereum)

Response:

{
  "chainId": 1,
  "chainName": "Ethereum Mainnet",
  "totalEndpoints": 15,
  "workingEndpoints": 12,
  "lastUpdated": "2026-02-07T14:13:42.104Z",
  "endpoints": [
    {
      "url": "https://eth.rpc.pinax.network",
      "status": "working",
      "clientVersion": "geth/v1.14.0",
      "blockNumber": 19123456,
      "error": null,
      "testedAt": "2026-02-07T14:13:42.104Z"
    },
    ...
  ]
}

GET /chains

Get all indexed chains.

Query Parameters:

• tag (optional): Filter chains by tag (e.g., Testnet, L2, Beacon)

• family (optional): Filter by technology family from the research dataset. Labels are free text (OP Stack / Zora, Matchain / OP Stack), so this is a case-insensitive substring match: ?family=op stack finds every OP Stack chain

Example: GET /chains?tag=Testnet

Response:

{
  "count": 1234,
  "chains": [ ... ]
}

Example Chain Object:

{
  "chainId": 80002,
  "name": "Amoy",
  "shortName": "polygonamoy",
  "theGraph-id": "polygon-amoy",
  "fullName": "Polygon Amoy Testnet",
  "caip2Id": "eip155:80002",
  "aliases": ["amoy-testnet", "amoy"],
  "nativeCurrency": {
    "name": "POL",
    "symbol": "POL",
    "decimals": 18
  },
  "explorers": [ ... ],
  "infoURL": "https://polygon.technology/",
  "sources": ["chains", "theGraph"],
  "tags": ["Testnet", "L2"],
  "status": "active",
  "bridges": [
    {
      "url": "https://bridge.polygon.technology/"
    }
  ]
}

Note: Chain info no longer includes rpc or relations fields. Use /endpoints/:id for RPC endpoints and /relations/:id for chain relations.

GET /chains/:id

Get a specific chain by its chain ID. Unlike the list, the single-chain response also carries the chain's research block when it has research items or a hardware research entry (including checks that found no profile; see below). price is the native-asset quote or null when unavailable. The OpenAPI response schema documents the 200 detail and 400 / 404 error bodies; optional source metadata is retained rather than stripped by response serialization.

Example: GET /chains/80002 (Amoy)

Response:

{
  "chainId": 80002,
  "name": "Amoy",
  "shortName": "polygonamoy",
  "theGraph-id": "polygon-amoy",
  "fullName": "Polygon Amoy Testnet",
  "caip2Id": "eip155:80002",
  "aliases": ["amoy-testnet", "amoy"],
  "nativeCurrency": {
    "name": "POL",
    "symbol": "POL",
    "decimals": 18
  },
  "explorers": [
    {
      "name": "polygonscan-amoy",
      "url": "https://amoy.polygonscan.com",
      "standard": "EIP3091"
    }
  ],
  "infoURL": "https://polygon.technology/",
  "sources": ["chains", "theGraph"],
  "tags": ["Testnet", "L2"],
  "status": "active",
  "bridges": [
    {
      "url": "https://bridge.polygon.technology/"
    }
  ],
  "price": null
}

GET /search?q={query}

Search chains by name or ID.

Example: GET /search?q=ethereum

Response:

{
  "query": "ethereum",
  "count": 15,
  "results": [ ... ]
}

GET /endpoints

Get endpoints (RPC, firehose, substreams) for all chains.

Response:

{
  "count": 4236,
  "endpoints": [
    {
      "chainId": 80002,
      "name": "Amoy",
      "rpc": [
        "https://rpc-amoy.polygon.technology",
        "https://polygon-amoy-bor-rpc.publicnode.com",
        ...
      ],
      "firehose": [
        "amoy.firehose.pinax.network:443"
      ],
      "substreams": [
        "amoy.substreams.pinax.network:443"
      ]
    },
    ...
  ]
}

GET /endpoints/:id

Get endpoints (RPC, firehose, substreams) for a specific chain by ID.

Example: GET /endpoints/80002 (Amoy)

Response:

{
  "chainId": 80002,
  "name": "Amoy",
  "rpc": [
    "https://rpc-amoy.polygon.technology",
    "https://polygon-amoy-bor-rpc.publicnode.com",
    "wss://polygon-amoy-bor-rpc.publicnode.com",
    "https://amoy.rpc.service.pinax.network"
  ],
  "firehose": [
    "amoy.firehose.pinax.network:443"
  ],
  "substreams": [
    "amoy.substreams.pinax.network:443"
  ]
}

GET /relations

Get all chain relations data.

Response:

{
  "count": 123,
  "relations": [ ... ]
}

GET /relations/:id

Get relations for a specific chain by ID.

Example: GET /relations/80002

Response:

{
  "chainId": 80002,
  "chainName": "Amoy",
  "relations": [
    {
      "kind": "testnetOf",
      "network": "matic",
      "chainId": 137,
      "source": "theGraph"
    },
    {
      "kind": "l2Of",
      "network": "sepolia",
      "chainId": 11155111,
      "source": "theGraph"
    }
  ]
}

GET /sources

Get status of data sources.

Response:

{
  "lastUpdated": "2026-02-07T14:13:42.104Z",
  "sources": {
    "theGraph": "loaded",
    "chainlist": "loaded",
    "chains": "loaded",
    "slip44": "loaded"
  }
}

GET /export

Export the disk cache snapshot file (DATA_CACHE_FILE) as JSON.

Returns:

• 200 with JSON snapshot content when the file exists

• 404 when the cache file does not exist

• 503 when cache is disabled (DATA_CACHE_ENABLED=false)

Response (example):

{
  "schemaVersion": 1,
  "writtenAt": "2026-02-23T12:34:56.000Z",
  "data": {
    "lastUpdated": "2026-02-23T12:34:56.000Z",
    "indexed": {
      "byChainId": {},
      "byName": {},
      "all": []
    }
  }
}

GET /slip44

Get all SLIP-0044 coin types as JSON. The table from the markdown file is converted to JSON format using "Coin type" as the key (id).

Response:

{
  "count": 1279,
  "coinTypes": {
    "0": {
      "coinType": 0,
      "pathComponent": "0x80000000",
      "symbol": "BTC",
      "coin": "Bitcoin"
    },
    "60": {
      "coinType": 60,
      "pathComponent": "0x8000003c",
      "symbol": "ETH",
      "coin": "Ether"
    }
  }
}

GET /slip44/:coinType

Get a specific SLIP-0044 coin type by its coin type ID.

Example: GET /slip44/60 (Ethereum)

Response:

{
  "coinType": 60,
  "pathComponent": "0x8000003c",
  "symbol": "ETH",
  "coin": "Ether"
}

GET /client-releases

Proxy for chains-client-feed (the feed has no public host, so the dashboard reads it through here). Releases and changelog entries, newest first.

Query: limit (1–500, default 100), fork (true = only releases announcing a hard fork), chainId, repo (owner/repo, optionally github:/gitlab:-prefixed), since (ISO date or date-time). All passed through to the feed.

Response: {fetchedAt, stale, count, items:[{id, url, title, publishedAt, source:{id, name, kind}, chains:[{chainId, name}], chainsFrom: "release"|"repository", release:{repo, tag, version, prerelease, mandatory}, enrichment:{class, createdAt, summary, fork, forks?}}]}. fork is {name, network, activationAt, activationBlock, state} plus activationEpoch / activationSlot / activationTimestamp when the notes state them. Missing upstream fields come back as null / [].

Related routes:

• GET /client-releases/clients?q=&kind=&chainId= — the client registry (repositories and name-only clients), each with kinds, names, networkCount, latestRelease, latestFork.

• GET /client-releases/clients/:host/:owner/:repo — one repository (host = github | gitlab; owner / repo = [A-Za-z0-9_.-]+, never only dots) with every network it serves (networks:[{chainId, name, kinds, source}]) — the reverse lookup. 404 when the feed does not know it.

• GET /client-releases/networks/:chainId — clients serving a chain, with the kinds each plays on that chain.

Errors: 503 {error: "Client release feed not configured"} when CLIENT_FEED_URL is unset; 502 when the feed fails and nothing is cached. Responses are cached per upstream URL for CLIENT_FEED_CACHE_TTL_MS.

Dashboard: Activity → Releases lists /client-releases?limit=200 (the Forks only toggle re-reads with fork=true) with chain and client filters; each card shows the repo linked to its release, version/tag, pre-release / mandatory badges, published time, the AI summary, a fork line (name, network, activation — a time only when one was stated, plus block/epoch/slot/timestamp — and state) and its chains (labelled Repository networks when the notes named none). The chain drawer gains a Clients section from /client-releases/networks/:chainId, where Supports N networks expands the client's other networks (each opens that chain). Both stay hidden when the API answers 503.

POST /reload

Reload data from all sources.

Response:

{
  "status": "success",
  "lastUpdated": "2026-02-07T14:13:42.104Z",
  "totalChains": 1234
}

GET /validate

Validate chain data for potential human errors across all three data sources.

This endpoint analyzes the chain data and identifies potential inconsistencies or errors based on the following rules:

1. Rule 1 - Relation Conflicts: Assumes graph relations are always true and finds conflicts with other sources

2. Rule 2 - slip44/Testnet Mismatch: Chains with slip44=1 but isTestnet=false

3. Rule 3 - Name/Tag Mismatch: Chain full names containing "Testnet" or "Devnet" but not tagged as Testnet

4. Rule 4 - Sepolia/Hoodie Networks: Chains containing "sepolia" or "hoodie" keywords but not identifying as L2 or having no relations

5. Rule 5 - Status Conflicts: Deprecated status conflicts across different sources

6. Rule 6 - Goerli Deprecation: Chains containing "Goerli" keyword but not marked as deprecated

Response:

{
  "totalErrors": 85,
  "summary": {
    "rule1": 3,
    "rule2": 57,
    "rule3": 16,
    "rule4": 1,
    "rule5": 1,
    "rule6": 7
  },
  "errorsByRule": {
    "rule1_relation_conflicts": [...],
    "rule2_slip44_testnet_mismatch": [...],
    "rule3_name_testnet_mismatch": [...],
    "rule4_sepolia_hoodie_issues": [...],
    "rule5_status_conflicts": [...],
    "rule6_goerli_not_deprecated": [...]
  },
  "allErrors": [...]
}

Example Error Object:

{
  "rule": 6,
  "chainId": 5,
  "chainName": "Goerli",
  "type": "goerli_not_deprecated",
  "message": "Chain 5 (Goerli) contains \"Goerli\" but is not marked as deprecated",
  "fullName": "Goerli",
  "status": "active",
  "statusInSources": []
}

Data Structure

Chain Object (from /chains endpoints)

Each chain object returned from /chains and /chains/:id contains:

• chainId: The chain ID (extracted from caip2Id for The Graph data)

• name: Full name of the chain

• shortName: Short name/symbol

• theGraph-id: The Graph network identifier (if available from The Graph)

• fullName: Full network name (if available from The Graph)

• caip2Id: CAIP-2 identifier, e.g., "eip155:1" (if available from The Graph)

• aliases: Alternative names array (if available from The Graph)

• nativeCurrency: Native currency information

• explorers: Array of block explorers

• infoURL: Information URL. Where the research dataset moved a chain to a different website (or filled a missing one), this is the corrected one, with infoURLSource: "research" and the registry's original kept in registryInfoURL

• family: Technology family (e.g. OP Stack-derived), from the research dataset

• sources: Array of data sources that provided this chain's data

• status: Chain status - defaults to "active" when not present in any data source

• tags: Array of tags (e.g., "Testnet", "L2", "Beacon")

• bridges: Array of bridge URLs (if available from chainlist or chains.json parent.bridges field)

Note: Chain objects no longer include rpc or relations fields. Use /endpoints/:id for RPC endpoints and /relations/:id for relations.

research (from /chains/:id only)

A static, audited research dataset (data/network-research.json, ~3,000 chains), converted from the network research and verification workbook, plus the forum research (data/forum-research.json), the node hardware research (data/node-hardware.json) and the communication channel research (data/channel-research.json). Network research items include only checked/partial evidence whose audit was not unresolved; forums and channels include confirmed/qualified records. Hardware retains every researched entry and profile, including unresolved profiles and empty results with status, notes and sources. The block is omitted only when there are no research items or hardware research entry (family is still set on the chain itself). Optional raw metadata is retained at every level.

• family, coverage (checked / partial / not_found / inaccessible), auditStatus (confirmed / qualified / corrected / unresolved / no_populated_claims_to_audit), checkedAt, updatedAt (dataset date)

• repositories[]: node/client source — url, repo (owner/name for GitHub), kind (node, execution, consensus, rollup, packaging, sdk, contracts, other), kindLabel (original wording), status, audit, evidence[]

• papers[]: whitepapers and documents — url, title, status, audit, evidence[]

• features[]: short sourced statements — text, status, audit, evidence[]. These are project statements, not tested facts

• forums[]: discussion boards the forum research tied to the chain (from data/forum-research.json, ~600 chains) — url, title, type (governance / community / developer / research / general), relationship (official / community_run / uncertain), scope (exact_network, project_family = the project's shared board, ecosystem_shared, historical_network, uncertain), access (read / inaccessible / archived at research time), activity (recent_activity_observed / historical_or_archived / unknown), lastActivity, verification (confirmed / qualified), notes, evidence[]; plus forumsCheckedAt. Only confirmed or qualified records are included. This is research, not the polled registry: the chain's forumUrl still comes from the curated data/forums.json, which is what chains-forum-news reads

• channels[]: public community / developer / support routes the channel research found linked from a primary project source (from data/channel-research.json, ~1,400 chains), most specific first — platform (discord, telegram, x, email with a mailto: url, slack, gitter, matrix, wechat, contact_form, other), url, canonicalUrl (where the link resolves, when different), title, mode (discussion / announcements / support / mixed / unknown), audience[], language, relationship (official_operated / officially_endorsed = linked by the project, not necessarily run by it / community_run / uncertain), scope (as for forums), access (public_preview_read, public_discussion_read, invite_unverified, login_required, inaccessible, not_checked, at research time), invitation (verified_preview / official_link_unverified / not_applicable / unknown), lastActivity, alternateInvites[], verification (confirmed / qualified), notes, evidence[]; plus channelsCheckedAt. Optional activity, checkedAt, evidenceMode, current_availability_checks[] (including raw activity_status) and independent_verification retain the newer availability revision's evidence and timestamps. Only confirmed or qualified records are included and repurposed links are dropped. No channel was joined and nobody was contacted, so this is a discovery list, not evidence that a channel is active or answered. get_chain_by_id sends at most 12, compacted — each platform gets a slot before any repeats — with channelsTotal and per-platform counts in channelsByPlatform

• hardware: documented node sizing from the node hardware research (data/node-hardware.json, ~3,100 researched chains, ~900 with profiles; a chain with none still carries the research status (not_found / inaccessible), notes and checked sources) — status, notes, sources[], identityStatus (confirmed / qualified / unresolved: how firmly the research tied the documentation to this chain), checkedAt, and profiles[], one per role × tier × client: role (full_node, validator, archive, rpc, collator, sequencer, prover, light_node, other, unspecified), level (minimum / recommended / example / unspecified), scope (exact_network or project_family = the project's generic sizing, not verified for this exact network; historical_network; uncertain), client, clientVersion, deployment (current / historical / deprecated / unknown), verification, notes, verificationNotes, evidence[], and requirements[] — component (cpu, memory, storage, network, gpu, operating_system, other), metric (cores, vcpus, threads, capacity, storage_type, bandwidth, os_version, …), value (number, string or boolean), unit as published (GB vs GiB, Mbps vs MB/s, cores vs vCPU are not interchangeable and are never converted), qualifier (as_stated / at_least / at_most / approximately / range, with min / max for ranges), notes, source. An omitted component means nothing was documented, never zero. prerequisiteFor[] links a profile to another role it supports (role, requiredWhen, sizing, notes, sources), preserving its original role and counting it once; Nibiru's full-node profile is a validator prerequisite, while the linked sizing: "not_established" means dedicated validator sizing remains undocumented. A profile can also be an extra component to run alongside the node: requiredWhen gives the condition (OP Mainnet's Legacy Geth / l2geth, for pre-Bedrock historical state), sizing says how far its hardware is documented (explicit / partial / not_established — such a profile may have no requirements), historicalStateEra the era it serves, snapshotArtifact a published download (file, type, sizes[] exactly as labelled — a download size, not a disk target), and dependencies[] the other services the node needs (component, requiredWhen, clientOptions, selfHosted, hosting, sizing). Every profile is included, unresolved ones too (verification unresolved: the source or its applicability was not settled — treat it as unverified); these are published requirements, not benchmarks. The dashboard does not render this block: it exists so the assistant and MCP clients can answer node setup questions, through the get_node_requirements tool

status is checked (fully verified) or partial (evidence gaps or uncertain applicability). audit is the item-level audit result: confirmed, qualified (family/historical/source caveats remain), corrected or null.

Endpoints Object (from /endpoints endpoints)

Each endpoints object returned from /endpoints and /endpoints/:id contains:

• chainId: The chain ID

• name: Chain name

• rpc: Array of RPC endpoints (strings or objects with url and metadata)

• firehose: Array of The Graph firehose endpoints (if available)

• substreams: Array of The Graph substreams endpoints (if available)

Relations Object (from /relations/:id endpoint)

Relations data contains:

• chainId: The chain ID

• chainName: Chain name

• relations: Array of relations to other chains

  • Each relation contains: kind, network (network ID), optionally chainId (resolved chain ID), and source (data source)

  • Relation kinds: testnetOf, mainnetOf, l2Of, parentOf, beaconOf

  • Relation sources: theGraph, chainlist, chains

  • Reverse relations: After all relations are indexed, reverse relations are automatically created:

    • mainnetOf: Added to mainnets pointing to their testnets (reverse of testnetOf)

    • parentOf: Added to L1 chains pointing to their L2 chains (reverse of l2Of)

  • chainlist relations: When slip44 === 1 or isTestnet === true, finds mainnet by matching tvl field value with chains where isTestnet === false

    • Note: tvl matching is based on chainlist data structure; this field may represent a chain identifier rather than Total Value Locked in some contexts

  • chains.json relations: When parent.type === "L2", creates l2Of relation using parent chain ID extracted from parent.chain field (format: eip155-<chainId>)

    • Example: Mode Testnet (919) has parent: { type: "L2", chain: "eip155-11155111" }, creating a l2Of relation to Sepolia (11155111)

SLIP-0044 Data Structure

Each SLIP-0044 coin type object contains:

• coinType: The coin type number (used as the key/id)

• pathComponent: BIP-0044 path component in hexadecimal

• symbol: Coin symbol

• coin: Full coin name

Documentation

More detailed information about project internals and testing can be found in the docs folder:

• Project Structure: Detailed explanation of files and directories

• Testing: Comprehensive guide to the testing strategy (Unit, Integration, and Fuzz testing)

Contributing

We welcome contributions to the Chains API project! Whether you're fixing bugs, improving documentation, or proposing new features, your contributions are appreciated.

How to Contribute

1. Fork the repository and create your branch from main

2. Make your changes with clear, descriptive commit messages

3. Add or update tests to cover your changes

4. Ensure all tests pass by running npm test

5. Verify code quality - your changes will be automatically scanned by SonarQube

6. Submit a pull request with a clear description of your changes

Code Quality Standards

All contributions must meet our quality standards:

• ✅ All tests must pass (300+ test cases)

• ✅ Code coverage ≥ 80%

• ✅ Code duplication ≤ 3%

• ✅ No critical code smells or security vulnerabilities

• ✅ Cognitive complexity within acceptable limits

These standards are automatically enforced through our CI/CD pipeline and SonarQube analysis.

Areas for Contribution

• 🐛 Bug fixes and issue resolution

• 📚 Documentation improvements

• ✨ New features and enhancements

• 🧪 Additional test coverage

• 🔍 Data validation and quality improvements

• 🌐 Support for additional blockchain networks

Questions or Issues?

If you have questions or encounter issues, please open an issue on GitHub.

License

MIT