Cells
In TON, a cell is like a small box that can hold information. Each box (cell) has two parts inside:
- it can keep up to 1023 bits of data (like a small note inside the box)
- it can point to up to 4 other boxes (arrows to other cells)
There are some rules:
- data and arrows are kept separately
- arrows cannot go in circles — a box cannot point back to itself, directly or indirectly
Because of this, all cells together form a directed acyclic graph (DAG). You can imagine it as a family tree: every child points to parents, but you can never circle back to your great-grandparent.
These design choices allow us to define the following rules for cells:
- Storage is compact and efficient (cells can be reused in multiple places).
- Verification is simple (Merkle proofs can show that data is correct).
- Serialization is standardized (Bag of Cells).
Types of cells
There are five types of cells in TON. One is the normal cell, and four are special (called exotic).
| Type | Think of it as... | Purpose |
|---|---|---|
| Ordinary cell | A regular box | Default, stores most data |
| Pruned branch | A “summary” of many boxes | Used for short proofs |
| Library reference | A shared folder everyone can use | Helps avoid duplicates |
| Merkle proof | A certificate attached to a box | Used for verification |
| Merkle update | A “change log” for a set of boxes | Used for updating state |
Serialization of data into cells
In TON, everything is stored in cells: messages, blocks, even the whole blockchain state.
All these objects are broken down into trees of cells. This tree is called a Bag of Cells (BoC). You can imagine it as a set of nested boxes inside boxes.
To describe how exactly data is put into boxes, TON uses a special language called TL-B. It plays the same role as Protocol Buffers or JSON schemas, but for TON cells.
Transition to cells
When a transaction happens:
- Validators execute smart contracts inside the TVM.
- The resulting changes are written to account states.
- These account states are stored as cells, which are then committed into blocks.
Thus, cells are the fundamental building blocks of TON’s data storage.