TL;DR — We are standardizing how ALeRCE data is accessed and retiring direct (raw SQL) connections to the ALeRCE database. If you use our website, the ALeRCE API, or the Python client, nothing changes for you. If you connect to the database directly (e.g. from a Jupyter notebook), please switch to our TAP service (tap.alerce.online) — a standard astronomical query endpoint (IVOA TAP / ADQL) that runs the same kind of queries over the web and works out of the box with tools like TOPCAT, pyvo, and astroquery.
What’s changing
ALeRCE exposes its data through several supported interfaces — the website and Explorer, the ALeRCE API, the Python client, our example notebooks, and the TAP service for SQL-style queries. We are consolidating around these interfaces and phasing out ad-hoc direct database connections, which are harder to support, tie your code to our internal schema, and don’t follow community standards.
TAP is the recommended replacement for anyone who was writing SQL against the database directly, and it’s available right now — you don’t have to wait for any of the dates below to start migrating. It speaks ADQL (a SQL dialect for astronomy), supports cone searches and cross-matches, and is interoperable with the standard Virtual Observatory tooling. Visit tap.alerce.online for connection instructions (including the exact service URL) and to browse the available tables — the multisurvey data (alerce_tap schema) and ZTF-legacy (ztf schema) are both served there today.
Timeline (approximate)
- Late June 2026 — the database is frozen: existing data stays available, but no new data is written into the ZTF-legacy dataset.
- ~3 months read-only window — direct connections keep working (read-only) so you have time to migrate.
- Around September 2026 — direct database access is removed. TAP and our other interfaces (all already live) remain the way to query the data.
Your data is not going away. After direct access is removed, both the multisurvey database and ZTF-legacy remain fully queryable through TAP and our other interfaces.
A note for ZTF users
ZTF data is currently served through our ZTF-legacy dataset, so for now please continue to access ZTF data there. We expect to migrate all ZTF data into the multisurvey database before the end of 2026, and we will announce it when that happens. ZTF-legacy will remain available well beyond that — there is no removal date, and it will not be retired before 2027.
What to do
- Most users: nothing.
- Direct-DB users: review the full migration guide and move your queries to TAP (or the API / Python client) before the read-only window ends. You can start today — no need to wait.
Our example notebooks at github.com/alercebroker/usecases are being updated to use TAP instead of direct database calls; the TAP versions will be available in the repo within the next couple of days, giving you a ready-made starting point. Once they’re up, if you’ve saved an older copy of one of these notebooks that still connects to the database directly, pull the updated version from the repo (or adapt your own copy to TAP).
Questions? See the full migration guide or ask us in the LSST Community forum using the tag alerce.