Open standard

An open standard for complex tables in Markdown, including multi-row headers, merged cells, and sections.

LTEM (LLM-friendly Table-Enhanced Markdown) is a free, open standard that extends Markdown tables. It represents complex table structures, including merged cells, multi-row headers, and sections, in plain text that people and AI can read.

A free, independent open standard developed by EurekaAI. The LTEM paper will be presented at EMNLP 2026 in Budapest, October 24–29.

Official LTEM website

LTEM source and table preview. Revenue spans the Q1 and Q2 columns, while Region spans both header rows.

Why LTEM matters

Real documents often contain complex tables

Reports, forms, and official documents often contain tables with merged cells and multi-row headers. LTEM preserves these structures in plain text that people and AI can read, extending what standard Markdown tables can represent.

Examples

Explore LTEM through seven examples

Each example shows the LTEM source on the left and the rendered table on the right.

LTEM example with the Keynote cell spanning the Room A and Room B columns. — Merge cells across columns with `<<`The Keynote cell spans the Room A and Room B columns.

LTEM example with the Asia and Europe cells each spanning two rows. — Merge cells across rows with `^^`The Asia and Europe cells each span two rows.

LTEM example with the Closed cell spanning all five weekday columns in the noon row. — Span multiple columns with `{c:N}`The Closed cell spans all five weekday columns at noon, equivalent to using `<<` four times.

LTEM example with the Workshop cell spanning two columns and two rows. — Merge across columns and rows with `{c:N,r:M}`One Workshop cell spans a 2 × 2 area.

LTEM example with both rows above the separator displayed as header rows. — Stack header rows above `|---|`Both rows above the separator become headers, without changing their text.

LTEM example with Revenue spanning Q1 and Q2, and Region spanning both header rows. — Group columns under one headerRevenue spans Q1 and Q2, while Region spans both header rows.

LTEM example dividing a table into Travel cards and Cash-back cards sections that share the same columns. — Divide a table into sectionsBoth sections share the same column structure.

In use

An open standard, free for everyone

Cellmark Editor uses LTEM to represent and edit complex tables. Explore the full specification on the official LTEM website.

Explore

Cellmark Editor