<p>Solidity provides four ways to declare the visibility of a function and state variable in a contract. Here's a run through of all of them.</p>
<h1 id="heading-private">Private</h1>
<p>Private state variables and functions , can only be called or referred to by the parent contract. External and child contracts have no access. The name <em>private</em> dosen't imply you should store sensitive info in state variables, everything on the blockchain is public. So avoid doing that to keep your app secure .</p>
<p><img src="https://cdn.hashnode.com/res/hashnode/image/upload/v1650920388987/6J-OreQx8.png" alt="private_keyword.png" /></p>
<h1 id="heading-internal">Internal</h1>
<p>Similar to private , state variables and contracts cannot be called or referred to by external contracts, but the major difference is , child contracts have access to state variables and functions.</p>
<p><img src="https://cdn.hashnode.com/res/hashnode/image/upload/v1650920433386/LVQyyY-8w.png" alt="internal_keyword.png" /></p>
<h1 id="heading-public">Public</h1>
<p>This allows everyone ( external contracts , child contracts  , e.t.c ) . To have access to state variables and functions. When declared as public , the compiler automatically generates getters , which allow other contracts to read their values.</p>
<p><img src="https://cdn.hashnode.com/res/hashnode/image/upload/v1650920476543/TRzLpaVP7.png" alt="public_keyword.png" /></p>
<h1 id="heading-external">External</h1>
<p>This prevents the contract from being called from within . it can only be called by external contracts. This keyword cannot be applied on state variables. Trying to call an external contract from within , throws and error. </p>
<p><img src="https://cdn.hashnode.com/res/hashnode/image/upload/v1650920521010/SEkXObyrB.png" alt="external_keyword.png" /></p>


Solidity provides four ways to declare the visibility of a function and state variable in a contract. Here's a run through of all of them.

# Private

Private state variables and functions , can only be called or referred to by the parent contract. External and child contracts have no access. The name *private* dosen't imply you should store sensitive info in state variables, everything on the blockchain is public. So avoid doing that to keep your app secure .

![private_keyword.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1650920388987/6J-OreQx8.png)


# Internal

Similar to private , state variables and contracts cannot be called or referred to by external contracts, but the major difference is , child contracts have access to state variables and functions.

![internal_keyword.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1650920433386/LVQyyY-8w.png)

# Public

This allows everyone ( external contracts , child contracts  , e.t.c ) . To have access to state variables and functions. When declared as public , the compiler automatically generates getters , which allow other contracts to read their values.

![public_keyword.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1650920476543/TRzLpaVP7.png)

# External

This prevents the contract from being called from within . it can only be called by external contracts. This keyword cannot be applied on state variables. Trying to call an external contract from within , throws and error. 

![external_keyword.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1650920521010/SEkXObyrB.png)



There are four ways to declare the visibility of functions and state variables in a solidity contract. Here's a run through of all of them.

Visibility in Solidity

Understanding visibility keywords in solidity.

Table of contents

Private

Internal

Public

External