# olebedev/when

A natural language date/time parser with pluggable rules

Repository: https://github.com/olebedev/when
Canonical: https://ross.abutalabs.com/products/olebedev-when
Language: Go
License: Apache-2.0
License Family: permissive
Topics: natural-language, datetime, date, time, parser, golang
Last push: 2026-08-10T01:28:37+00:00

## Health v2 (maintenance only)
Score: 66/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 96, release rhythm 8, longevity 100
- inputs: {"age_days": 3536, "days_push": 24, "days_rel": 659, "gap_med": null, "n_releases_24m": 1}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1461, forks 93 (observed 2026-08-28T04:04:47.441777+00:00)

## What it is
when is a Go library that parses natural language date and time expressions like 'tonight at 11:10 pm' or 'next tuesday 14:00' into concrete timestamps. It uses pluggable rules and merge strategies, with support for English, Russian, Brazilian Portuguese, Chinese, and Dutch.

## Use cases
- parse dates from natural language text in Go
- extract datetime from user input like 'next friday at 3pm'
- build a reminder or scheduling feature that understands phrases
- convert phrases like 'tonight at 11:10 pm' to timestamps
- parse multilingual date expressions including Russian and Chinese
- find date mentions inside free-form chat messages

## When to choose
- you need a Go library for natural language date parsing
- you want pluggable, extensible parsing rules
- you need multilingual date parsing (EN, RU, BR, ZH, NL)
- you want a lightweight alternative to heavyweight NLP services

## When to avoid
- you need date parsing in a language other than Go
- you need languages beyond the five supported ones
- you need full NLP entity extraction beyond dates and times

## Facets
- artifact type: library
- maturity: active
- function: parser, nlp, date-time
- domain: parsers, developer-tools
- platform: go, cross-platform
- tags: natural-language-dates, pluggable-rules, multilingual, golang-library, natural-language-processing

## Member repositories
- olebedev/when (main) score 66

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:47.441777+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 2026-08-30T04:35:21.489664+00:00, confidence not recorded.
  - readme: https://github.com/olebedev/when (fetched 2026-08-28T04:04:47.441777+00:00, sha 163f796b2e71)
- Data as of 2026-08-30T08:39:29.467469+00:00.