TL;DR: if you use ALeRCE through our websites (Explorer, SN Hunter), the ALeRCE API, the Python client, the cross-match or catsHTM tools, nothing changes for you. The one thing going away is the ability to connect directly to our database with a host, username, and password (psql, psycopg2, SQLAlchemy, JDBC, etc.). If that’s how you query us (e.g. through jupyter notebooks), please move to our TAP service at tap.alerce.online — a standard astronomical query endpoint (IVOA TAP / ADQL) that works out of the box with TOPCAT, pyvo, and astroquery. TAP is live now, so you can start migrating today.
What’s changing
ALeRCE offers data through several interfaces: our websites (Explorer, SN Hunter), the ALeRCE API, the Python client, the cross-match and catsHTM tools, and the TAP service for SQL-style queries. All of these stay exactly as they are.
The only method we’re phasing out is the direct database connection — pointing psql, psycopg2, SQLAlchemy, a JDBC driver, etc. at our database with a host, port, username, and password. Direct connections tie your code to our internal table layout, are hard to keep stable and secure, and aren’t part of the standard astronomy data-access ecosystem. TAP is the replacement: the same queries, through a documented, standard interface.
This is not a data freeze. ALeRCE keeps ingesting and serving data as usual — TAP, the API, and our websites all stay live and up to date, including ZTF data. The change below affects only people who connect to the database directly.
What is TAP, and what’s in it
TAP (Table Access Protocol) is the IVOA standard for querying astronomical tables over the web. You write ADQL (SQL plus astronomy functions — cone searches, cross-matches, etc.), and it works from TOPCAT, pyvo, astroquery, or any IVOA-compliant client — no database credentials needed.
Everything you could reach through a direct connection is available in TAP:
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the
ztfschema: ZTF data (ztf.object,ztf.detection,ztf.forced_photometry,ztf.magstat, etc.). For ZTF, use this schema. -
the
alerce_tapschema: our main multi-survey catalog (alerce_tap.object,alerce_tap.detection,alerce_tap.probability,alerce_tap.feature, etc.).
Note:
alerce_tapalso contains ZTF tables, but they are not ready for use yet — please keep using theztfschema for ZTF data for now. We’ll announce when the ZTF tables underalerce_tapare ready.
Connection instructions, the exact service URL, and a browsable list of every table and column are at tap.alerce.online and in our Data access (TAP) guide.
Timeline
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07/07/2026 (next week) — the database reached through the direct connection is frozen: from then on it’s a static snapshot and won’t receive new data. Every ALeRCE service keeps updating as normal — so if you want continuously-updated data, that’s your cue to move to TAP, where the data keeps flowing.
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~3-month read-only window — your existing direct connection keeps working (read-only) so you have time to migrate your queries.
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Around October 2026 — direct database connections are switched off. TAP and our other interfaces (all already live) remain the way to query the data.
Your data is not going away — only the direct-connection method is. Everything stays fully queryable through TAP and our other services.
What to do
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Use our websites (Explorer, SN Hunter), the API, Python client, cross-match, or catsHTM? Nothing.
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Connect directly with a host/username/password? Switch your queries to TAP (or the API / Python client). You can start today — no need to wait for any of the dates above.
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Using an older copy of one of our example notebooks? If it connects to the database directly, it will stop working when direct access is removed. Pull the updated version from the repo (or replace its direct-DB calls with TAP).
Our example notebooks at github.com/alercebroker/usecases were recently updated to use TAP in place of direct database calls, giving you ready-made, working ADQL examples to adapt to your own analysis.
Questions? See our documentation, the Data access (TAP) guide, or just reply here on the forum (tag alerce).