Divide long text lists, bulk email databases, SQL query records, URLs, SKU lists, and massive datasets into custom batches, equal parts, delimiter segments, or byte-limited chunks in real time. Features 100% in-browser client-side privacy, multi-file .txt batch downloads, JSON array-of-arrays export, unified canvas with dynamic header tokens, and instant zero-latency processing for 50,000+ items.

Universal In-Memory Batch Slicing Engine

Universal Text List Splitter

Divide long lists and datasets into equal batches, specific chunk sizes, custom delimiter groups, or multiple downloadable parts in real time with 100% client-side privacy.

Total Input Items 0 Items

Batches Generated 0 Batches

Items per Batch 0 Items/Batch

Remainder / Last Batch 0 Items (Even)

Quick Presets:

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Source List Items

Drop text/CSV file here or click to browse (.txt, .csv, .tsv, .json, .log)

Splitting Strategy

📏 Fixed Chunk Size Every N lines per batch 🗂️ Equal Groups / Parts Divide into N equal parts ✂️ Delimiter / String Break on custom delimiter 💾 Character / Byte Limit Max chars/bytes per batch

Lines / Items per Batch:

Quick sizes:

Target Number of Batches / Groups:

Quick parts:

Split Delimiter / Marker String:

Presets:

Max Characters per Batch:

Quick limits:

Group Header Format (in Unified View): Enable Headers

Tokens: {N} (batch #), {COUNT} (items), {TOTAL} (total batches), {START} (item start #), {END} (item end #)

List Hygiene & Cleaning

Trim Whitespace Remove leading & trailing spaces

Ignore Blank Lines Filter out empty items

Deduplicate Items Keep only unique items

Number Output Items Prefix with 1. 2. 3...

Batch 1 of 1

Batch #1 0 items • 0 characters

Showing 0 batches

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Enter or paste text items to view the multi-batch card showcase.

Batch Chunking, SMTP Limits & Data Partitioning Reference

Why Slicing Email Lists into Batches Prevents SMTP Throttling & Blacklisting

Leading email service providers (such as Amazon SES, SendGrid, Mailgun, Google Workspace, and Microsoft 365) enforce strict rate limits on recipient counts per transaction (typically 50 to 500 recipients per batch) and hourly burst quotas. Transmitting unsegmented lists containing thousands of contacts simultaneously triggers automated anti-spam heuristic filters, resulting in immediate 421 / 450 Too Many Connections throttling, high bounce spikes, and IP reputation degradation.

By chunking your contact database into 250 to 500-recipient segments, you can stagger scheduled email dispatches across hourly intervals, ensuring high inbox deliverability rates and compliance with ISP warmup guidelines.

SQL Query Parameter Limits & Optimizing Bulk INSERT Statements

Relational databases impose hard limits on parameter placeholders and query packet payloads:

SQLite: Enforces a default host parameter limit of 999 (raised to 32,766 in version 3.32.0+). Large IN (...) queries or bulk insertions exceeding this limit cause fatal exceptions.
PostgreSQL: Restricts prepared statement query parameters to a maximum of 65,535 (16-bit integer limit).
MySQL / MariaDB: Constrained by the max_allowed_packet buffer configuration (defaulting to 16MB or 64MB).

Partitioning dataset lists into batches of 100 to 500 items ensures query parameters remain well within database engine limits while keeping transaction memory footprint minimal.

Fixed Chunk Size vs. Count-Based Group Partitioning & Remainder Handling

Understanding which splitting strategy fits your workflow is critical for balanced task scheduling:

Fixed Chunk Size (e.g., $N = 250$): Slices consecutive segments of exact size $N$. The final chunk contains the remaining modulo elements ($items \pmod N$). Ideal for API pagination, bulk webhook calls, and upload limits.
N Equal Groups / Parts (e.g., 4 parts): Computes dynamic batch sizes using $\lceil total / N \rceil$ to divide datasets evenly among $N$ workers, outreach reps, or parallel threads.
Delimiter / String Splitting: Breaks lists whenever a designated delimiter string (like ---, ===, or blank lines) appears, preserving structural document boundaries.
Character / Byte Limit: Dynamically calculates cumulative character lengths to guarantee that no single batch exceeds text token limits (e.g., LLM context windows or SMS gate limits).

100% In-Browser Privacy & Zero-Transmission Architecture

Your confidential data never leaves your device. All parsing, array slicing, whitespace trimming, deduplication, regex evaluation, and multi-file text downloads are computed strictly within your browser's local JavaScript runtime. No email lists, database dumps, CSV records, or split chunks are ever transmitted to an external server or stored in cookies.