Developer resources - SQD Documentation

Everything needed to build against SQD, at predictable URLs. If you are an agent, start with llms.txt and openapi.json.

The API

The Portal is a plain HTTP API serving onchain data from 140+ networks. No node, archive, or indexer of your own.

Resource	URL
Base URL	`https://portal.sqd.dev`
OpenAPI specification	openapi.json
Reference and playground	Portal API reference
First query	Portal quickstart
Dataset list	`GET https://portal.sqd.dev/datasets`

Your first request, which needs nothing installed:

curl -s -X POST https://portal.sqd.dev/datasets/ethereum-mainnet/stream \
  -H 'content-type: application/json' \
  -d '{"type":"evm","fromBlock":18000000,"toBlock":18000000,
       "fields":{"block":{"number":true,"timestamp":true}}}'

Responses to the stream endpoints are JSON Lines, read incrementally rather than buffered whole.

Access

The public Portal is shared capacity, intended for development and bounded evaluation. Authenticated and dedicated portals take an API key in the x-api-key header, with identical paths and payloads. See Pricing for the options.

Behaviour to code against

Error handling: the single error envelope, the four error types, and when to retry.
Versioning and change policy: what is stable, and how deprecations are announced.
Finalized and recent data and blockchain forks: following the chain head without diverging on a reorg.

MCP servers

Two servers, for two different jobs.

Server	Endpoint	Use it for
Portal MCP	`https://portal.sqd.dev/mcp`	Querying onchain data as agent tools
Documentation MCP	Docs search	Answering questions from these docs

The Portal MCP server exposes 28 tools covering EVM, Solana, Bitcoin, Substrate, and Hyperliquid queries, plus analytics, wallet summaries, and OHLC series.

SDKs

SDK	Use it for	Quickstart
Pipes SDK	Streaming pipelines into ClickHouse, PostgreSQL, BigQuery, or Parquet	Quickstart
Squid SDK	Indexers that serve a generated GraphQL API over PostgreSQL	Quickstart
Portal API	Any language, no dependencies	Quickstart

SDK overview compares the three against the same job.

Files for agents

File	What it is
llms.txt	Index of the documentation, with guidance on when to reach for SQD
llms-full.txt	Full text of every page in one file
openapi.json	The Portal API, with an operationId on every operation
skill.md	What agents can build with SQD
ai-catalog.json	Discovery document listing the above

Every page on this site is available as Markdown by appending .md to its URL, and through Accept: text/markdown content negotiation.

Data coverage

All networks lists every dataset the Portal serves, its ecosystem, and its start block. Available datasets is the same catalogue written for agents.

Where to ask

Reason	Where
Technical questions	Telegram community or `[email protected]`
Dedicated portals, pricing, volume	Contact SQD
Data protection and privacy	`[email protected]`, imprint

SQD is operated by Subsquid Labs GmbH, Bahnhofstrasse 7, 6300 Zug, Switzerland. For what changed and what is changing:

Announcements for deprecations and retirements
Changelog for what shipped
FAQ for the common questions

​The API

​Access

​Behaviour to code against

​MCP servers

​SDKs

​Files for agents

​Data coverage

​Where to ask