# base/pessimism

Detect real-time threats and events on OP Stack compatible blockchains

Repository: https://github.com/base/pessimism
Canonical: https://ross.abutalabs.com/products/pessimism
Homepage: https://base-org.github.io/pessimism/
Language: Go
License: MIT
License Family: permissive
Archived: true
Last push: 2024-05-29T20:34:08+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:39:23.370411+00:00)
- activity 0, release rhythm 8, longevity 90
- inputs: {"age_days": 1261, "days_push": 826, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1614, forks 484 (observed 2026-08-28T04:05:11.342307+00:00)

## What it is
Pessimism is a self-hosted monitoring service that continuously assesses OP Stack and EVM-compatible blockchains for real-time threats using user-defined heuristic rule sets. It was developed by Base as a public good but was deprecated in May 2024 and is no longer actively maintained.

## Use cases
- monitor OP Stack chains for real-time security threats
- alert on suspicious on-chain events
- define custom heuristic rules for blockchain anomaly detection
- watch EVM chain activity for risk conditions
- set up automated threat detection for rollup infrastructure

## When to choose
- studying blockchain threat monitoring architecture
- forking a heuristic-based chain monitoring service for your own needs

## When to avoid
- you need actively maintained blockchain monitoring
- you want production-ready threat detection with support
- you monitor non-EVM chains

## Facets
- artifact type: service
- maturity: abandoned
- function: monitoring, alerting, blockchain
- domain: blockchain, monitoring, security
- platform: go, self-hosted
- tags: op-stack, evm, real-time-threat-detection, heuristic-rules, deprecated, cryptocurrency, linux, docker

## Member repositories
- base/pessimism (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:11.342307+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:50:20.323867+00:00, confidence not recorded.
  - readme: https://github.com/base/pessimism (fetched 2026-08-28T04:05:11.342307+00:00, sha 596f44c7e8f8)
- Data as of 2026-08-30T08:39:29.467469+00:00.