Why run this instead of querying a public Stacks API?

Public APIs lack your contract, schema, and uptime guarantees; this keeps decoded data you own with backfill, verification, and local reads through Postgres, your own schema, or your existing serving path.

What does the subgraph workflow actually involve?

Scaffold a contract subgraph into TypeScript, deploy it from a recent block, then query typed tables with sorting and cursor paging or stream rows into your own schema.

Do I need a subgraph for simple event reactions?

No. Chain webhooks fire on raw events with contract and function triggers and POST to your app URL, while subgraphs remain the path for typed historical tables.

Which package do I install first?

Most apps need only the instance SDK for subgraphs, streams, index, and webhooks plus the CLI binary; the low-level Stacks client, MCP server, subgraph helpers, shared DB code, and REST API packages are for narrower roles.

What does the hosted option cost compared with self-hosting?

The hosted API at api.secondlayer.tools uses an account key and includes 1 million rows free every month. Self-hosting is Postgres plus one container on your own hardware; either way you get decoded chain data in your own database, backfilled from genesis and kept reorg-safe.

How does pagination work on subgraph queries?

Pages are _id-keyset: read next_cursor from a response and pass it as ?cursor= to resume, and use _order=asc or desc for direction. The SDK returns rows, next_cursor, and tip from sl.subgraphs.rows.

How do agents or the MCP server connect, and which token do they need?

Run bunx -p @secondlayer/mcp secondlayer-mcp, which defaults to the local API. For writes on your own instance, set INSTANCE_TOKEN from secondlayer init; against api.secondlayer.tools it uses SECONDLAYER_API_KEY instead, because the key follows the host.

CommunityJev Tools & CLIs

Secondlayer

Self-hosted Stacks runtime that backfills decoded chain data from genesis into your own database and serves it as tables, a REST API, or row streams.

See highlights

Open github.com

Stars: 7
Language: TypeScript
License: MIT
Published by: Community
Author: ryanwaits
Last verified: Oct 2026

ryanwaits/secondlayer

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Decoded Stacks data in your own database. Self-hosted.

Forks: 3
Last pushed: Updated Oct 2026

Repo stats from the GitHub API, cached Oct 2026.Homepage

About this project

Your app needs Stacks data that no public API has — your contract, your schema, your uptime. Today that means writing an indexer. Secondlayer is the runtime instead: decoded chain data in your own database, backfilled from genesis, reorg-safe, kept current. Get tables and a REST API out of the box, or stream rows into your own schema — Postgres, SQLite, or anything you already run — and serve them however you already serve things.

Quoted from the project's README. Read the full README.

Tagscommunity jevbest catalog-import

Works forJev for Classification

Used inJev for Software & DevTools

Languages: TypeScript

Highlights

Runs as Postgres plus one container on your hardware with reorg-safe indexing kept current from genesis.
Scaffolds and deploys TypeScript subgraphs that index contracts into typed queryable tables with keyset paging.
Fires chain webhooks on raw events without a subgraph using contract and function-name triggers.
Splits SDKs between an instance client for queries and webhooks and low-level Stacks chain primitives.

Watch out

Self-hosting needs Docker, CLI bootstrap against a manifest, and verification; check the self-host and package docs for the topology. Copy reviewed against the repository README on 2026-10-04, not from running it.

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