# Value Validation

Nobody enjoys typos, especially ones that make their way into production and cause outages. With CloudTruth you can set a series of rules and typing on your parameters to ensure they meet a specific criteria, or syntax, that meet specific intended values.

## Creating Parameter Rules

Rules are set on the parameter itself within a selected project that provide validation of values across all of the parameters environments.

The following are the current rules you can set on your parameters.

| Parameter Type | Allowed Rules                                                       |
| -------------- | ------------------------------------------------------------------- |
| String         | <p>Minimum Length</p><p>Maximum Length</p><p>Regular Expression</p> |
| Integer        | <p>Minimum</p><p>Maximum</p>                                        |
| Bool           | Boolean Types                                                       |

{% hint style="info" %}
We provide a regular expression rule for strings to come up with whatever crafty regex you require.
{% endhint %}

The Type and Rules can be set during parameter creation or when editing a parameter.

<figure><img src="/files/SMZ81P7bQW1nEN677Zjw" alt="" width="467"><figcaption></figcaption></figure>

<figure><img src="/files/MBcaF3xBrocJzv2K9HKU" alt="" width="563"><figcaption><p>Value typed is shorter than the minimum length</p></figcaption></figure>

<figure><img src="/files/esM6Rs1vL1xZaDEr3vsp" alt="" width="563"><figcaption><p>Value is longer than maximum allowed length</p></figcaption></figure>

{% hint style="info" %}
When adding rules to an existing parameter, CloudTruth will check across all environments to make sure the existing values conform to the new rule(s). If any of the values do *NOT* conform to the proposed rule change, the app will display the what and how the rule conflicts. Those conflicts will have to be remediated prior to setting the rule.
{% endhint %}

<figure><img src="/files/3n0Sz3k9B3jJK5ACFljW" alt="" width="464"><figcaption><p>Adding a rule to an existing parameter where an environment value does not match the rule </p></figcaption></figure>

<figure><img src="/files/0HqYerEniRcMWUS00bDI" alt=""><figcaption><p>Error message when rule cannot be applied due to an existing value mismatch</p></figcaption></figure>

The rule type and constraint settings are listed in the parameter's detail page for convenience.

<figure><img src="/files/aX3yhQ9wxrSF2XeLiHYm" alt=""><figcaption></figcaption></figure>


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