This blog goes over the connection account prerequisites and considerations when designing in NWC. All this information was generated and reference on 05/12/2016  and is subject to change without notice from the vendors that provide the end-point service. 

Box

The prerequisite is to use a Business Plan account and it has an API call limit which should be taken into account

when designing workflows.  

API account limits: 

Starter

• Box API Access: 25k actions per month

 Business 

• Box API Access: 50K actions per month

 Enterprise 

• Box API Access: 100K actions per month

Pricing :Plans and Pricing | Box 

Referenced from: Box Developer Platform   (Error Code reference) 

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ShareFile

This connector requires you to allow Nintex Workflow Cloud to access your ShareFile account, you will be prompted when setting up the connector.

API account limit: N/A

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DocuSign

The prerequisite is to enable the account to Send on behalf of functionality. SOBO functionality is only available to accounts that use the DocuSign API to send envelopes. It can be enabled for an account member by a DocuSign Customer Administrator through the DocuSign Console or by contacting your DocuSign Account Manager.

*You may need to check if your DocuSign account package allows for API calls, if not you will need to upgrade it to an Advanced Solutions package. Pricing and Packages 

API account limits: 

DocuSign has an API call limit of 1000 API calls per hour / per account (This is for Demo and Production Accounts). If the API call rate limit is reached, you will receive an exception for each call until the start of the next hour (this can be up to 60 minutes). The exception message states: “The maximum number of hourly API invocations has been exceeded” (error number 207)

Referenced from: API Call Rate Limits ; API - Send on Behalf of Functionality | DocuSign

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Dropbox  

The prerequisite is to use a Business Plan account it has an API call limit which should be taken into account when designing workflows.  

API account limit: N/A

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Google Drive

No prerequisite for account plan. The API limit may very on the account plan you have. 

API account limit : 1000 requests per user per 100secounds 

Note: Although per-user limits are specified in queries per second, we permit short-term usage spikes. Therefore, you should set your limits based on sustained average traffic levels. If anyone tries to use an API in excess of these settings, the requests will trigger a limit exceeded error.

Referenced from: Capping API usage - API Console Help 

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Marketo

You will need to you have an account set with the appropriate permissions. Please see the getting started section here http://developers.marketo.com/rest-api/ (They have a special API permission set that can be assigned to the account. 

API account limit: API access per instance limited to 100 calls per 20 seconds.

Daily Quota: Most subscriptions are allocated 10,000 API calls per day (which resets daily at 12:00AM CST). You can increase your daily quota through your account manager.

Concurrency Limit: Maximum of 10 concurrent API calls.

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Microsoft Dynamics CRM

This is currently to Microsoft Dynamics CRM tenants only. So it is the online version. A trust is created between the NWC Connection Hub and the Microsoft Dynamics CRM service when creating the connection. You will need an administrative account for CRM to setup the connection.

API account limit: N/A

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Microsoft OneDrive for Business Beta

Requires a business account.

API account Limit: N/A 

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Microsoft SQL Server 

This service will need to be setup by your Database / Network team to make the SQL instance publically accessible. 

Nintex Help: Linked here

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MySQL

This service will need to be setup by your Database / Network team to make the MySQL instance publically accessible. 

Nintex Help: Linked here

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PostgreSQL

This service will need to be setup by your Database / Network team to make the PostgreSQL instance publically accessible.

Nintex Help: Linked here

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Salesforce

User account will need to have API enabled option

Setup ->Manage Users -> Profiles -> Under the "Administrative Permissions" area there is the "API Enabled" check box.

API account limit: 

The following table lists the limits for various types of orgs for concurrent requests (calls) with a duration of 20 seconds or longer.

The following examples illustrate API usage metering calculations for several scenarios.
For an Enterprise Edition org with 15 Salesforce licenses, the request limit is 30,000 requests (15,000 + 15 licenses X 1,000 calls).
For an Enterprise Edition org with 60 Gold Partner licenses, the request limit is 27,000 (15,000 + 60 licenses X 200 calls).
For an Enterprise Edition org with 15,000 Salesforce licenses, the request limit is 1,000,000. The number of licenses X 1,000 calls is greater than the maximum value, so the lower limit of 1,000,000 is used.
For a Developer Edition org that made 14,500 calls at 5:00 AM Wednesday and 499 calls at 11:00 PM Wednesday, only one more call could successfully be made until 5:00 AM Thursday.

Referenced from: Salesforce Developers

If you get insufficient privileges error on some objects you will need to check individually the object permissions in Salesforce, you may need the assistance of the Salesforce Administrator. 

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Slack

Accounts do not have prerequisites. 

API account limits: 

In general Slack allow applications that integrate with Slack to send no more than one message per second. Slack allow bursts over that limit for short periods. However, if your app continues to exceed the limit over a longer period of time it will be rate limited.

If you go over these limits when using our HTTP based APIs, including Incoming Webhooks, Slack will start returning a HTTP 429 Too Many Requests error, a JSON object containing the number of calls you have been making, and a Retry-After header containing the number of seconds until you can retry.

If you go over these limits when using our Real Time Messaging API you will receive an error message as a reply. If you continue to send messages your application will be disconnected.

Continuing to send messages after being rate limited runs the risk of having your application permanently disabled.

Referenced from: Rate Limits | Slack

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Twilio

API account limits: N/A 

Loop protection

To protect your account, messages cannot be sent more than 15 times in a 30 second window between your Twilio phone number and another number. Doing so may trigger a 14107 warning that your message rate has been exceeded.

Nintex Help: Linked here

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Zendesk 

API Account Limits: 

This API is rate limited. Zendesk only allow a certain number of requests per minute depending on your plan and the endpoint. Zendesk reserve the right to adjust the rate limit for given endpoints to provide a high quality of service for all clients. As an API consumer, you should expect to be able to make the following number of requests per minute:

Nintex Help:  Linked here