# nylas/sync-engine

:incoming_envelope: IMAP/SMTP sync system with modern APIs

Repository: https://github.com/nylas/sync-engine
Canonical: https://ross.abutalabs.com/products/sync-engine
Homepage: https://nylas.com/docs/platform
Language: Python
License: AGPL-3.0
License Family: copyleft
Archived: true
Last push: 2026-06-25T18:21:11+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 89, release rhythm 8, longevity 100
- inputs: {"age_days": 4613, "days_push": 69, "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 3496, forks 344 (observed 2026-08-28T04:08:07.361199+00:00)

## What it is
The Nylas Sync Engine is an open-source email sync platform that exposes a RESTful API on top of IMAP/SMTP, letting applications read and send mail, contacts, and calendar data across providers. The repository is archived and no longer maintained; its capabilities live on in the fully-hosted Nylas API.

## Use cases
- sync email accounts via imap into a rest api
- build apps on top of email without imap plumbing
- self-host an email sync engine
- read gmail messages through a rest api
- send email programmatically over smtp
- unify mail contacts and calendar data behind one api

## When to choose
- you need a historical reference implementation of an imap/smtp sync engine
- you want to study how a rest api was layered over imap/smtp
- you can maintain the sync logic yourself and accept no upstream updates

## When to avoid
- you need a maintained, production-ready email sync solution
- you want Exchange support, which the open-source version never included
- you want vendor support or a hosted option - use the commercial Nylas API instead
- you are starting a new project - the repo is archived

## Facets
- artifact type: service
- maturity: abandoned
- function: http-server, api-framework, email, webhook, caching
- domain: email, apis, backend, self-hosted, developer-tools
- platform: python, self-hosted
- tags: imap, smtp, email-sync, rest-api, archived, vagrant, mysql, inbox-api, linux, docker, web-server

## Member repositories
- nylas/sync-engine (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:07.361199+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 2026-08-29T18:35:53.623012+00:00, confidence not recorded.
  - readme: https://github.com/nylas/sync-engine (fetched 2026-08-28T04:08:07.361199+00:00, sha f7ecd3ac7cd2)
  - homepage: https://nylas.com/docs/platform (fetched 2026-08-29T09:30:13.648006+00:00, sha a4350cf02f7a)
  - site_page: https://developer.nylas.com/docs/v3/getting-started/cli (fetched 2026-08-29T09:30:13.666157+00:00, sha 1e0425d6d636)
  - site_page: https://developer.nylas.com/docs/v3/getting-started/dashboard (fetched 2026-08-29T09:30:13.667811+00:00, sha 744efe218f19)
  - site_page: https://developer.nylas.com/docs/v3/getting-started/coding-agents (fetched 2026-08-29T09:30:13.669757+00:00, sha 2e307b304451)
  - site_page: https://developer.nylas.com/docs/reference/api (fetched 2026-08-29T09:30:13.657067+00:00, sha d4ec87f4f153)
  - site_page: https://developer.nylas.com/docs/reference/notifications (fetched 2026-08-29T09:30:13.659322+00:00, sha 554b23e8df93)
  - site_page: https://developer.nylas.com/docs/reference/ui (fetched 2026-08-29T09:30:13.660956+00:00, sha 88a4c955d0d4)
  - site_page: https://developer.nylas.com/docs/cookbook (fetched 2026-08-29T09:30:13.662790+00:00, sha 0449a63724d0)
  - site_page: https://developer.nylas.com/docs/v3/getting-started (fetched 2026-08-29T09:30:13.664397+00:00, sha c24481194725)
- Data as of 2026-08-30T08:39:29.467469+00:00.