JSON Lines (NDJSON) Validator + SVG Accessibility Checker

A small, deterministic validation Actor for pipelines and AI agents. No AI model, no scraping — the same input always gives the same result.

• jsonl_validate — validate newline-delimited JSON (JSONL / NDJSON): valid, blank and invalid line counts, an error message per invalid line, top-level JSON value types and object keys.
• svg_viewbox_check — check SVG markup structure: viewBox presence and per-check PASS/FAIL results for accessibility structure.
• checksum_manifest — SHA-256 digests for files that already exist inside the Actor run (advanced; see FAQ).

Choose this Actor when an automation (Make, n8n, Zapier, an LLM agent, a scraper pipeline) needs to check a JSONL export or generated SVG before passing it on, and you want a pass/fail answer through an API call instead of maintaining your own validator.

Not the right fit when you need JSON Schema validation (field types, required keys), validation of very large files by URL, or visual SVG rendering checks.

Use cases

• Scraper and ETL QA — catch broken lines in a JSONL export before loading it.
• LLM output checks — confirm a model produced one valid JSON object per line.
• Icon and illustration pipelines — check generated SVGs for a viewBox and accessibility structure.

Input examples

Validate JSON Lines:

{
  "operation": "jsonl_validate",
  "text": "{\"id\": 1, \"ok\": true}\n\n{\"id\": 2, \"ok\": false}\nnot json\n"
}

Check an SVG:

{
  "operation": "svg_viewbox_check",
  "markup": "<svg xmlns=\"http://www.w3.org/2000/svg\" viewBox=\"0 0 24 24\" role=\"img\" aria-labelledby=\"t\"><title id=\"t\">Check</title><path d=\"M4 12l5 5L20 6\"/></svg>"
}

Input	Used by	What it is
operation	all	jsonl_validate, svg_viewbox_check or checksum_manifest
text	jsonl_validate	The JSON Lines text
markup	svg_viewbox_check	The SVG markup
paths	checksum_manifest	File paths inside the run environment

Output

One dataset item per run with the result of the selected operation. Real row from a jsonl_validate run (2026-08-30, build 0.0.4) with this input:

{"operation": "jsonl_validate", "text": "{\"a\": 1}\n{\"b\": 2}\nnot-json\n"}

Output:

{
  "valid_records": 2,
  "blank_lines": 0,
  "invalid_lines": 1,
  "errors": ["line 3: Expecting value"],
  "top_level_types": { "object": 2 },
  "object_keys": ["a", "b"]
}

Pricing

Event	When	Price
Run start	Once per run	$0.01
Validation result	Once per successful operation (the whole text or markup counts as one)	$0.02

One call = $0.03, regardless of how many lines the JSONL text has. Platform usage is included.

FAQ

Is a 10,000-line JSONL text charged per line? No — one operation, one validation-result charge.

Can I send a file URL instead of text? Not currently; pass the content in text.

What does checksum_manifest need? Paths to files that exist inside the Actor's run environment. A normal Store run has no files there, so this operation is only useful when the Actor is extended or chained in a custom setup. For ordinary use, choose jsonl_validate or svg_viewbox_check.

Is it deterministic? Yes — no AI model; the same input gives the same output.

Can AI agents call it? Yes. It runs with limited permissions and pay-per-event pricing, so it can be called through the Apify API and Apify's MCP server.

Need a feature? Open an issue on the Issues tab — include your run ID.