> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sqd.dev/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Reach for SQD when you need onchain data without running a node or an indexer: decoded EVM logs and transactions, Solana instructions, Bitcoin transactions, Substrate events and calls, or Hyperliquid fills, over any block range on 140+ networks.
> To query directly, POST to https://portal.sqd.dev/datasets/{dataset}/stream. The full API is described at https://docs.sqd.dev/openapi.json, and responses to the stream endpoints are JSON Lines.
> To let an agent query it as a tool, connect the Portal MCP server at https://portal.sqd.dev/mcp.
> Every page on this site is available as Markdown by appending .md to its URL.

# Versioning and change policy

> How the Portal API changes, how deprecations are signalled, and what stays stable.

The Portal API carries no version in its URL. There is no `/v1/`, and no
version header. Every client talks to the same surface at
`https://portal.sqd.dev`, and the endpoints below are the whole of it:

```bash theme={"system"}
curl -s https://portal.sqd.dev/datasets | head -c 120
```

That works because the surface grows by addition. New dataset types, new block
and transaction fields, and new datasets appear without changing what an
existing request means.

## What you can rely on

| Stable                                                    | Not stable                                                  |
| --------------------------------------------------------- | ----------------------------------------------------------- |
| Endpoint paths and HTTP methods                           | The prose in `error.message`                                |
| The error envelope `{"error":{"type","code","message"}}`  | The order of datasets in `GET /datasets`                    |
| `error.type` as a closed set of four values               | The set of datasets, which grows and is occasionally pruned |
| `error.code` values, which stay meaningful once published | Worker assignments in `GET /datasets/{dataset}/state`       |
| Field names in a selector once accepted                   |                                                             |

Match on `error.code`, never on `error.message`. See
[Error handling](/en/portal/introduction/error-handling) for the full table of
types and codes.

## Detecting a change

The machine-readable description of the whole API is published at
[openapi.json](https://docs.sqd.dev/openapi.json). Every operation there has a
stable `operationId`, and the field selectors are enumerated per dataset family.
That document is the one to diff in a pipeline, or to regenerate a client from.

For a quick answer at a terminal, the Portal also describes itself. Send a field
name it does not know and the rejection names the accepted set:

```bash theme={"system"}
curl -s -X POST https://portal.sqd.dev/datasets/ethereum-mainnet/stream \
  -H 'content-type: application/json' \
  -d '{"type":"evm","fromBlock":1,"toBlock":1,"fields":{"block":{"nope":true}}}'
```

```json theme={"system"}
{"error":{"type":"invalid_request_error","code":"malformed_request",
 "message":"Bad request: unknown field `nope`, expected one of `number`, `hash`, `parentHash`, `timestamp`, ..."}}
```

The same trick works on `type`, which answers with every dataset family the
Portal serves.

<Warning>
  Read that list yourself; do not parse it in a client. It arrives inside
  `error.message`, which is prose and is not part of the contract, so it can be
  reworded at any time. Automated checks belong against
  [openapi.json](https://docs.sqd.dev/openapi.json), which is versioned and
  structured for exactly this.
</Warning>

## Datasets change, the API does not

The surface that moves is the dataset catalogue, not the endpoints. Datasets
are added as networks are onboarded, and occasionally retired when a network is
deprecated upstream or demand disappears.

Retirements are announced in advance on the
[Announcements](/announcements) page and in the
[Telegram community](https://t.me/HydraDevs), with the affected datasets named
and a date. Past examples:

* [May 2026 gateway deprecations](/announcements/gateway-deprecations-may-2026):
  Eclipse, Goerli and Fantom retired on May 21, with Fuel, Starknet and Solana
  following on June 1.
* [August 2026 dataset retirements](/announcements/dataset-retirements-august-2026):
  67 datasets retired on August 20, with migration guidance per dataset.

To check whether a dataset is still served, call
`GET /datasets/{dataset}/metadata`. A retired name answers `404` with
`error.code` of `unknown_dataset`:

```bash theme={"system"}
curl -s https://portal.sqd.dev/datasets/no-such-dataset/metadata
```

```json theme={"system"}
{"error":{"type":"invalid_request_error","code":"unknown_dataset","message":"Unknown dataset: no-such-dataset"}}
```

<Note>
  Watch the [Announcements](/announcements) page rather than polling for
  removals. An automated consumer that treats `unknown_dataset` as fatal will
  fail on the day of a retirement it could have been warned about.
</Note>

## SDK versioning

The SDKs are versioned independently of the Portal, as npm packages following
semantic versioning. Breaking changes land in a major release with a migration
guide, and the Portal continues to serve older SDK versions: the wire format
they depend on is the same additive surface described above.

## Rate limits and retries

The public Portal is shared capacity. When it is at capacity it answers
`rate_limit_error` with an `overloaded` code and a mandatory `Retry-After`
header. [Error handling](/en/portal/introduction/error-handling) covers the
retry rules, which headers are exposed through CORS, and how `x-request-id`
ties a report back to a single request.

Authenticated and dedicated portals take an API key in the `x-api-key` header.
The paths and payloads are identical either way. See
[Pricing](/en/portal/pricing) for the access options.


## Related topics

- [Developer resources](/developers.md)
- [EVM fallback data source](/en/sdk/squid-sdk/evm/reference/evm-fallback.md)
- [Packages overview](/en/sdk/squid-sdk/evm/reference/packages-overview.md)
- [Pricing Details & Examples](/en/cloud/pricing/pricing-details.md)
- [Schema changes and backfills](/en/cloud/resources/schema-changes-and-backfills.md)