Use delta sync to detect changed tables efficiently

Discover which tables have been updated since your last sync without fetching every endpoint. The Trassets Data API GET /changes endpoint returns metadata for changed tables and supports conditional requests via ETag to skip polling when nothing is new.

Poll /changes every 15–60 minutes. The underlying sync runs as a daily batch, so polling more often will not surface newer data — it only spends more of your 500 req/h budget. Combine this with the since/ETag pattern below so unchanged polls stay cheap.

Poll for changed tables

Send a GET request to /changes with an ISO-8601 UTC since timestamp. The response lists every table whose last_sync_at is after that timestamp, including the corresponding endpoint URL.

curl -s "https://api.trassets.ai/changes?since=2026-07-01T00:00:00Z" \
  -H "X-API-Key: $TRASSETS_API_KEY"

Example response:

[
  {
    "table_name": "properties",
    "last_sync_at": "2026-07-07T06:00:00",
    "category": "property",
    "api_table_name": "properties",
    "endpoint_url": "/property/properties"
  },
  {
    "table_name": "ixhaus_contracts",
    "last_sync_at": "2026-07-07T06:05:00",
    "endpoint_url": "/raw/ixhaus_contracts"
  }
]

Fetch only changed tables

For each item returned by /changes, request the corresponding endpoint only. Skip any table that is absent from the response. This avoids unnecessary data transfer and preserves your 500 req/h rate limit budget.

Use conditional GET on subsequent polls

Store the ETag header from the first successful /changes response. On your next poll, send it back as If-None-Match.

curl -s "https://api.trassets.ai/changes?since=2026-07-01T00:00:00Z" \
  -H "X-API-Key: $TRASSETS_API_KEY" \
  -H "If-None-Match: \"abc123\""

If no tables have changed since the ETag was issued, the API returns 304 Not Modified with an empty body and does not count the request against the change-data query cost.

Advance the since parameter

After a successful sync, store the current timestamp and use it as the since value for the next poll. This creates a sliding window so each run evaluates only the interval since the previous run.

Full Python example

A complete poller that tracks the since timestamp and ETag between runs, and only processes tables that actually changed. Requires the requests package.

poll_changes.py

import os
from datetime import datetime, timezone

import requests

API_KEY = os.environ["TRASSETS_API_KEY"]
BASE_URL = "https://api.trassets.ai"
HEADERS = {"X-API-Key": API_KEY}


def poll_changes(since: str, etag: str | None = None):
    """Poll /changes and return (changed_tables, new_etag, new_since).

    changed_tables is an empty list on a 304 Not Modified response.
    """
    headers = dict(HEADERS)
    if etag:
        headers["If-None-Match"] = etag

    resp = requests.get(
        f"{BASE_URL}/changes", headers=headers, params={"since": since}, timeout=30
    )

    now = datetime.now(timezone.utc).isoformat()
    if resp.status_code == 304:
        return [], etag, now

    resp.raise_for_status()
    return resp.json(), resp.headers.get("ETag"), now


if __name__ == "__main__":
    since = "2026-07-01T00:00:00Z"
    etag = None

    changed, etag, since = poll_changes(since, etag)
    for table in changed:
        print(f"Changed: {table['table_name']} -> {table['endpoint_url']}")
    if not changed:
        print("No changes since last poll.")

    # Persist `since` and `etag` and pass them into the next scheduled run.

The since parameter must not be older than 30 days. Requests with a timestamp beyond this lookback window return an error. Run a full table refresh if your last successful sync was more than 30 days ago.

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Use delta sync to detect changed tables efficiently