Best Free CSV, Chart, and File Inspector Tools

This roundup maps ToolComb tools that stay in the browser for table cleanup, quick charts, fair bill splits, archive inspection, and lightweight EPUB metadata. It is not a ranking of every SaaS spreadsheet. It is a routing guide with honest limits: local processing, no account, and no pretending a filename list neutralizes malware.

Decision tree: one problem, one tool

Your problem	Open first	Deep-dive
“This export has duplicate headers and blank rows”	CSV Editor	Clean CSV in the browser
“I need a bar chart PNG for a deck”	Chart Maker	CSV to chart PNG workflow
“Dinner for six with shared appetizers and one vegan”	Bill Splitter	Bill splitter tips
“What is inside this .zip before I extract?”	ZIP Inspector	ZIP and EPUB basics
“Calibre shows the wrong author on my EPUB”	EPUB Metadata Editor	Same ZIP/EPUB guide
“API wants JSON; I only have CSV”	CSV to JSON	How to convert CSV to JSON
“Client sent JSON; I need a CSV for Mail merge”	JSON to CSV	Why CSV to JSON fails (reverse pitfalls)

CSV Editor: grid surgery before conversion

Exports from CRMs, ad platforms, and “Save As CSV” in Excel rarely arrive RFC-clean. Title rows above headers, trailing commas, semicolon locales, and sep= hints are normal. CSV Editor lets you paste or open a file, edit cells, add or delete rows and columns, and download a cleaner CSV - without uploading the grid to finish the edit.

Use it when the failure is visible in the first ten rows: wrong delimiter guess, a BOM-prefixed header, or a summary line you need to delete before CSV to JSON. Use How to clean CSV tables when you want a repeatable checklist (encoding, header row, empty lines).

What it will not do: infer types across ten thousand rows, run SQL, or merge databases. Very wide or very long sheets can stress browser memory. That is a RAM ceiling, not a reason to paste a customer dump into an unknown cloud editor.

Chart Maker: from small table to PNG

Chart Maker is for one dataset, one chart image. Paste CSV-like rows or type labels and values, pick bar, line, pie, or related types, tune colors and labels, export PNG. Slides, Notion, GitHub READMEs, and support tickets want a static chart more often than they want a live embed.

Pair it with CSV Editor when the source export has footers or comment lines. Pair it with CSV to chart PNG workflow when you care about axis labels, heatmaps vs bars, and when to stop cleaning in the spreadsheet app.

What it will not do: refresh when the Google Sheet changes, enforce corporate brand fonts from a template library, or replace When to use a heatmap in UX for research synthesis - though you may export a heatmap-style chart for a readout.

Bill Splitter: tables for people, not schemas

Bill Splitter belongs in the same local tab family as CSV tools but solves a different equation: subtotal, tax, tip, shared items, and per-person totals. Freelancers splitting a client dinner and roommates splitting groceries both want transparent math, not a uploaded receipt photo stored on a server.

Read Bill splitter tips for shared appetizers, uneven drinks, and rounding. For invoice PDFs and contracts, the business hub still wins - Best free business tools for freelancers.

ZIP Inspector and EPUB Metadata Editor: look, don’t trust blindly

ZIP Inspector lists entries, sizes, and compression method inside a ZIP in the browser. Useful for “did this build artifact include .env?” or “is this EPUB just a renamed folder?” Not useful as security clearance for attachments from people you do not trust. Malware can live in nested archives; listing names is not scanning; extracting in the browser still executes parser code on bytes you chose to load.

EPUB Metadata Editor reads the EPUB (ZIP + OPF) package and edits common metadata fields. Fix a typo in the author field before sideloading to a reader. It does not replace Sigil or Calibre for structure edits, TOC rebuilds, or embedded font licensing.

Both tools: local processing, no account. Both tools: read Privacy checklist before you share a file if the archive might contain PII.

CSV ↔ JSON: when the grid becomes an array

After cleanup, conversion is the bridge to scripts and APIs. CSV to JSON and JSON to CSV run in the tab. Happy path: How to convert CSV to JSON. Unhappy path: Why CSV to JSON fails.

Keep numbers as strings when leading zeros matter. Keep dates as ISO strings when locale slashes lie. JSON is not “more correct” than CSV - it is a different shape for a different consumer.

What these tools deliberately exclude

This cluster is not:

• A malware sandbox or enterprise DLP scanner for ZIPs
• A full ebook studio (layout, CSS, accessibility audit)
• Google Sheets with sharing and revision history
• Looker / Metabase with scheduled dashboards
• A legal tax engine for bill splits across jurisdictions

Browser tools win on privacy-sensitive one-offs: one export, one chart, one metadata fix, one split dinner. They lose on collaboration at scale and untrusted binary inspection.

Blog cluster map (data and office adjacent)

1. How to clean CSV tables in the browser - encoding, headers, delimiters
2. CSV to chart PNG workflow - Chart Maker + clean data
3. Bill splitter tips and fair splits - shared items and rounding
4. ZIP inspector and EPUB metadata basics - limits and safety
5. Why CSV to JSON fails - Excel dialects
6. How to convert CSV to JSON - happy path

Privacy across the hub

Processing runs client-side in your browser. ToolComb does not need your file on an application server to complete CSV edit, chart render, ZIP listing, EPUB metadata write, or bill math. Site assets and analytics still load. Shared computers and sensitive exports still deserve redaction and policy checks - see What not to paste into online developer tools.

The honest roundup

Free csv editor chart maker online is really four questions: Is the table clean? CSV Editor. Do I need a picture of the trend? Chart Maker. Who pays what? Bill Splitter. What is in this container? ZIP Inspector and EPUB Metadata Editor - with eyes open about malware and ebook scope. When the destination is code, finish with CSV to JSON or JSON to CSV after the grid tells the truth.