For Users

Limits, Scalability, Constraints

The system works, I presume you have learnt that by now. But when does it stop working? What could possibly break it? This document clarifies any restrictions coming from our technological partners.

Creating your own Voiceflow diagram

We currently only support Voiceflow .vf diagrams upon upload and the limits of these include:

  • Built with only supported blocks.

    • Supported blocks include speak, block, interaction, start, and command.


  • Interaction blocks are limited to 2 choices.

    • There should be only two outgoing connections from one interaction block. The first being yes and the second being no. No more or less choices are currently supported, and the top node must be Yes and the bottom must be No.


  • Maximum 597 speak nodes.

    • Voiceflow diagram should not exceed more than 597 nodes with type speak.


Deploying your own bots

When it comes to uploading and deploying your own chatbot, the limits include:

  • 50 Bots per Twilio account.

    • You can have 50 of these chatbots deployed at one time.
  • 64 number of characters for a chatbot name.

    • Due to Twilio, the maximum number of characters you can use to name your chatbot is limited to 64.
  • Name must fit specific format. format

    • When naming your chatbot, only create a name with letters and numbers with spaces replaced by hyphens.

Users interacting with bots.

When users text your chatbot, there are a few limits which may effect how quickly a user gets a message or what you can send.


  • Around two seconds response time.

    • Usually a single message is broken down into one or two message segments so you can expect a message to take around 1 or 2 seconds to reach a user.
  • Around 7200 messages can be sent at one time from a phone number.

    • Twilio puts messages onto a queue before being sent to a user and this queue is estimated to only hold around 7200 messages at one time.
  • Can handle ~500 messages per second from users per phone number.

    • It’s estimated that Twilio can handle 500 messages per second from users at a given time per phone number.
  • ~100 users can talk to a chatbot at a single time.

    • Due to limits with Twilio, only around 100 people per second can be interacting with a chatbot.
  • Currently support only UK long code phone numbers.

    • Limited to only processing long code numbers and no support for shortcode.