01
Column names never match your schema
"Email Addr", "contact email", and "e_mail" all point at the same field.
✓
Rowslint suggests a mapping based on headers and sample values, and asks the user to confirm.
csv & excel importer for saas onboarding
Stop losing users during CSV import. Give them an import flow that actually finishes.
Rowslint is a CSV and Excel import widget you drop into your app. Your users upload a messy file, the AI guesses the column mapping, validation flags the bad rows in their browser, and your backend gets clean data ready to write.
npm i @rowslint/importer-js Read the docs
01 Users fix their own errors before they submit.
02 The AI guesses column mapping so they don't have to.
03 You stop chasing import edge cases on the side.
Product preview From a messy spreadsheet to clean rows
Upload · Map · Fix · Import rowslint · import customers
v2.4.1
1
Upload2
AI map3
Fix4
SendDrop a customer CSV or Excel file
parsed locally · validated before import
.csv.xlsx.xls.tsv
messy-customers.csv0%
messy-customers.csv
Works with your stack
React
Vue
Svelte
Solid
Angular
Next.js
Nuxt
TypeScript
Lightweight streamed, in-browser
< 5 min quickstart path
Privacy-first rows stay in the tab by default
TypeScript first-class, end-to-end
why users abandon imports
CSV import is often the first place onboarding breaks.
A spreadsheet is usually the moment a prospect becomes an activated user. If the import flow feels confusing, slow, or unforgiving, they leave before your product has a chance to prove itself.
02
Validation errors show up too late
The user submits a file, waits a bit, and then your backend rejects row 387.
✓
The rules run in the browser, so bad rows get fixed before anything is sent to your app.
03
Large files make the page feel broken
The upload freezes, progress is unclear, and users refresh the tab before onboarding ever finishes.
✓
Chunked parsing keeps the UI moving while the rows are processed in the background.
04
Support ends up doing the import
Your team starts asking for screenshots, cleaning spreadsheets by hand, and re-running imports for customers.
✓
Users get guided fixes, can skip individual rows, and end up with clean import-ready output on their own.
built for paid-user moments
Use Rowslint where a failed import costs you a customer.
Rowslint isn't just a file picker. It's meant for the workflows where clean customer data unlocks the next paid step: activation, migration, account setup, and the recurring import tasks that keep your team busy.
Turn spreadsheet upload into activation.
New customers already have their data somewhere. A guided import path lets them reach the "aha" moment without needing a call with your team first.
- ✓ Map customer columns onto your schema
- ✓ Catch invalid rows before they hit the backend
- ✓ Send clean rows straight into your onboarding flow
Let accounts import their own data safely.
Give non-technical operators a branded importer for contacts, inventory, orders, members, leads, or whatever else they need to load, without opening up your admin tools.
- ✓ White-label the import experience
- ✓ Keep sensitive files in the browser by default
- ✓ Route the finished import to your webhook
Replace internal upload scripts with a real UI.
Your team shouldn't need a custom script every time ops receives a spreadsheet. Move the validation and review into the workflow itself.
- ✓ Preview rows before importing
- ✓ Skip or fix bad records inline
- ✓ Cut down on one-off data cleanup work
Stop spending roadmap time on CSV edge cases.
Every internal importer starts simple, then slowly grows mapping, validation, large file handling, retries, duplicate detection, and a small mountain of support debt. Rowslint ships all of that for you.
- ✓ Skip writing and maintaining parser logic
- ✓ Add AI mapping without rebuilding your UI
- ✓ Improve the import flow without a full rewrite
If a spreadsheet is part of activation, the quality of your import flow is the quality of your conversion.
Start free trial
Start with the workflow that blocks the most users, then roll Rowslint out to the next one.
how it works
Three steps, and you stop fielding import tickets.
Every import flow starts the same way and breaks in the same places. Rowslint covers the last 10% (the messy bit your users actually see) so you can focus on what happens once the data lands.
01
Embed in a couple of lines
One snippet for React, Vue, or plain JS. It picks up your theme tokens, your auth session, and your brand.
<button onclick="launch()">Drop a CSV</button>
02
Describe your schema
List the fields you expect, with types, regexes, enums, or async validators. Rowslint handles the rest.
schema.email().unique()
03
Users import, you get clean data
Rows arrive at your webhook or database already typed, deduplicated, and validated. Nothing sits on our servers.
webhook: "/api/import"
features
Built by people who've been on-call.
Every feature in Rowslint exists because someone, somewhere, got paged at 3am for a malformed CSV. We've seen the worst data you can imagine, and shipped defenses against it.
integrate
Two lines, no backend required.
Point Rowslint at a schema, give it a handler, and ship. Works with React, Vue, Svelte, or plain JS, and the TypeScript types are there from the first line.
ImportCustomers.tsx
jsx
1 import { launchRowslint } from "@rowslint/importer-js";
2
3 export function ImportCustomers() {
4 const launch = () =>
5 launchRowslint({
6 apiKey: process.env.ROWSLINT_API_KEY,
7 config: { templateKey: "customers_v3" },
8 onComplete: (rows) => save(rows),
9 });
10
11 return (
12 <button onClick={launch}>
13 Import customers
14 </button>
15 );
16 }
TypeScript-native
Your schema types flow through to the onImport handler. No anys, no casts.
Framework agnostic
@rowslint/importer-js, /react, /vue, /svelte all share the same API and bundle size.
Tree-shakable
Lightweight on purpose. Validators, the Excel parser, and locale bundles load on demand.
Headless mode
Bring your own UI and use the hooks for file parsing, mapping, and validation only.
column mapping
Your users' spreadsheet mess, mapped in milliseconds.
Rowslint fingerprints the file's headers and sample data against your schema. Fuzzy matches, synonyms, casing, whitespace, and common typos are handled before the user even sees the mapping screen, so most of the time they don't have to touch a thing.
Source file
Your schema
Email Addr [email protected]
email string
full_name Noah Chen
name string
org Acme Inc.
company string
signed up 2026-01-14
created_at datetime
status active
status enum
validation
Catch bad data before it reaches your backend.
Write your rules once with Zod, Yup, regex, or async fetches to your own API. Rowslint runs them on every row and surfaces errors inline, so users can fix them, skip them, or bulk-edit before anything leaves the browser.
validators.ts · 6 rules · 48,213 rows
runtime: 142ms
| Field | Rule | Sample | Status |
|---|---|---|---|
| z.string().email() | "[email protected]" | passing | |
| phone | z.string().regex(/^\+?[1-9]\d{7,14}$/) | "+14155550142" | passing |
| plan | z.enum(["free","pro","enterprise"]) | "pro" | passing |
| mrr | z.number().positive() | -32.00 | blocked |
| domain | async (v) => await checkDNS(v) | "acm.io" | review |
| created_at | z.coerce.date() | "2026-13-01" | blocked |
security & compliance
Reduce data exposure before the first import.
Rowslint is built so the risky part of a spreadsheet import happens as close to the user as possible. Rows get validated and reviewed in the browser, then only the clean result gets sent to a destination you control.
Browser-side by default
Parsing, mapping, and validation can all run before any customer data leaves the tab.
You pick the destination
Once an import is ready, the clean rows go to your webhook, database, or storage flow.
No AI vendor by default
Column suggestions are built so spreadsheet data doesn't have to be sent to a third-party AI API.
Enterprise controls
Self-hosted and customer-managed storage are available on request, just talk to us.
Trust checklist
Built for teams who have to answer security questionnaires.
- ✓ No file retention in the default import flow
- ✓ Users fix rows before anything is submitted to your backend
- ✓ Usage and CTA events are tracked separately from imported row data
- ✓ Documentation-first integration, so engineering can review before signing off
pricing
Start small. Upgrade when imports matter.
Pick the smallest plan that lets you prove out the import flow. Every paid plan comes with a 14-day free trial, no credit card needed. If you need something custom, drop us a line about an enterprise setup.
Free
Run the importer on a real workflow before you decide.
$0 /month
Start free - ✓ 100 file imports / month
- ✓ CSV and Excel import widget
- ✓ Basic validation rules
- ✓ Column mapping flow
- ✓ Developer quickstart
Recommended
For paid user flows Pro
For SaaS teams where a successful import affects activation.
$45 /month
Start free trial - ✓ 10,000 file imports / month
- ✓ Advanced data validation
- ✓ CSV and Excel formats
- ✓ Custom field mapping rules
- ✓ Webhook integrations
- ✓ Import analytics
- ✓ Priority support
Max
For teams running imports across multiple portals or ops queues.
$85 /month
Start free trial - ✓ 50,000 file imports / month
- ✓ Advanced validation workflows
- ✓ Custom branding
- ✓ API access
- ✓ Custom data transformations
- ✓ Dedicated support
Safe to try
14-day trial with no credit card required.
No surprise limits
You get usage alerts as you approach the cap, before imports are ever blocked.
No seat tax
Pricing follows import volume, not the number of teammates.
Private by default
Files are parsed and validated in the browser unless you opt into storage.
which plan?
Pick the plan that matches your import risk, not your company size.
Pick Free if you're just trying the workflow or testing a single import surface.
Pick Pro if imports are tied to onboarding, activation, or a paid customer journey.
Pick Max if several teams or customer portals run imports every month.
vs. alternatives
Faster to ship. Cheaper to run. Nicer to use.
We've built these systems before, in-house, with the competitors, and from scratch. Rowslint is the version we wish we'd had each time.
Rowslint
Flatfile-likes
In-house build
Rolling your own
Setup time
< 5 min
2–3 days
1 week
2+ weeks
Browser-side parsing
✓
✕
✕
✕
AI column matching
✓
✓
✕
✕
Large file support
✓
✕
✓
✕
Async validators
✓
✕
✕
✓
White-label theming
✓
✓
✕
✕
Self-hosted option
✓
✕
✕
✓
Compare Rowslint with Flatfile alternative CSVBox alternative useCSV alternative OneSchema alternative Dromo alternative
frequently asked
The questions we usually get first.
Couldn't find what you're looking for? Check the documentation →