CSV Import Previewer

Preview creates, updates, unchanged records and errors in a CSV import against your supplied snapshot. Download a row-by-row review without database writes.

Run and download

1. Keep the included sample or replace Input data with your own authorized records.
2. Start a run. Open Report and CSV downloads when it finishes.
3. Open OUTPUT for the complete JSON report and download the CSV records.
4. Review the findings before importing or publishing changes. This Actor never writes to a store.

Hosted limits

Up to 2000 CSV data rows, 2000 existing records and 1 MiB total input. These tighter hosted limits take precedence over the core format limits below. Memory is fixed at 256 MB. Default timeout is 60 seconds. Output includes one dataset summary row; individual findings and records are delivered in OUTPUT and CSV files. No model subscription, external API key or other product purchase is required.

Price

$0.05 per run, charged once when the Actor starts. All report and CSV output is included, with no per-row fee or platform-usage surcharge. Set the maximum run cost to at least $0.05. Starts that reject invalid input or produce no findings still incur the start charge; validate the input before running.

Storage and support

Apify stores supplied data and generated reports under its storage access/retention settings. This hosted edition sends input to Apify; it is not the local-only edition. Remove sensitive run data when no longer needed. URLs in input are never fetched. Use the Actor issue tracker for support with a non-sensitive example and run ID. Do not post private exports or credentials. Hosted use does not grant source redistribution rights.

Input contract

The JSON has csv (comma-separated text), key (the identifying field), fields (explicit mapping and rules), and optional existing (a snapshot array). Use the prefilled example. Every field declares column, type (string, number or date), and required (boolean). Optional min/max apply to numbers; enum is a list of literal allowed strings. No arbitrary regular expressions or executable validators are accepted. Identifiers must be required string fields. Each field maps to one unique, exact CSV header.

Existing records use exact string values, with unique, nonempty keys. Numbers are validated as plain decimals and dates as real YYYY-MM-DD calendar dates. All proposed values remain strings, preserving leading zeros and decimal precision; no numeric conversion is exported. Bounds use JavaScript numeric comparison, so use string-only fields for quantities requiring arbitrary-precision range comparisons.

All copies of duplicated input keys become errors. Missing fields and invalid values appear per record. Updates compare mapped fields to the existing snapshot; other fields are retained in existing evidence and are not proposed for deletion. Whitespace is preserved, not silently trimmed. Unmapped columns are explicitly reported and excluded from proposed records. CSV row numbers count logical data records, not lines inside quoted fields. Unknown headers do not silently become database fields.

Limits: 1 MiB input, 2000 data records, 100 columns/fields, 20000 characters per cell. CSV supports UTF-8 BOM, CRLF/LF, quoted commas, doubled quotes and embedded newlines. Malformed quoting, duplicate/blank headers and inconsistent row widths are refused. Only comma-separated UTF-8 input is supported. Export spreadsheets to CSV first.

JSON contains all records, before/after changes, errors and an input SHA-256. CSV is a review report, not a database import file; it protects formula-like prefixes. Nothing contacts or changes a database. This product intentionally has no commit feature: any real import must implement its own permissions and transaction handling. Snapshot freshness and correctness remain the user's responsibility.