# Amazon Lex bots in Amazon Connect Canonical: https://warmtransfer.net/knowledge/amazon-connect-lex-bots Last verified: 2026-09-25 Amazon Lex bots provide conversational speech and keypad input within Amazon Connect contact flows[^50]. AWS ended support for Amazon Lex V1 on September 15, 2025, making Lex V1 resources and its console inaccessible and directing migrations to Amazon Lex V2[^34]. ## How it works A Lex V2 bot is added to an Amazon Connect instance through the AWS Connect console by selecting the instance, opening Flows, and choosing the bot's Region, bot name, and alias under the Amazon Lex section[^5]. Upon association, Connect updates the bot's resource-based policy to grant Connect invocation permissions[^44]. Conversational AI bots powered by Lex can also be created and edited directly in the Connect admin website[^8]. Enabling bot management and analytics requires turning on those settings under Flows in the console and assigning the required security profile permissions[^18]. Service control policies (SCPs) blocking Lex prevent enabling this feature, but SCPs applied afterward are not respected and require manual deactivation[^45]. Lex V1 bots and cross-Region bots cannot be edited inside the Connect admin website[^40]. In contact flows, Lex bots are invoked using the Get customer input block, which can reference an alias from a dropdown or specify an alias ARN directly or dynamically via `LexV2Bot.AliasArn`[^4]. The Get customer input block is supported in inbound, customer queue, outbound whisper, transfer to agent, and transfer to queue flows, but cannot be used in customer hold, customer whisper, agent hold, or agent whisper flows[^23]. It supports voice contacts, supports chat contacts only when a Lex bot is used, and does not support task or email contacts[^22]. For chat contacts, the initial message can be populated from the customer's first message or a manual string up to 1,024 characters, and missing message attributes trigger the Error branch[^28]. Chat timeouts range from 1 minute to 7 days[^9]. Text-to-speech or chat text prompts in the block are capped at 3,000 billed characters and 6,000 total characters[^54]. The default text-to-speech voice in Amazon Connect is Joanna using conversational style[^14]. ## Flow logic and handoff The Get customer input block branches to configured intents, a Default branch when no configured intent matches, an Error branch when intent fulfillment fails, or a Timeout branch for chat timeouts[^21]. It can also evaluate customer sentiment on the last utterance before intent matching, prioritizing negative thresholds over positive thresholds[^46]. Intents do not populate the block's dropdown for Lex V1 bots, cross-Region bots, dynamically specified ARNs, or aliases lacking a published version and the `AmazonConnectEnabled=True` tag[^29]. Lex session attributes can drive subsequent routing blocks, such as Set working queue, Change routing priority / age, Transfer to flow, Transfer to phone number, Check contact attributes, and Set contact attributes[^32]. Wildcards (`*`) can be used for intent and slot keys within a block, but they do not apply across different Get customer input blocks[^57]. Values returned by a Lambda code hook take precedence over attributes set in the Get customer input block, which take precedence over service defaults[^47]. To hand off to an agent, reference flows wire the bot's SpeakToAgent intent branch to a Set working queue block followed by a Transfer to queue block[^27]. WarmTransfer's reading of the sources is that reading session attributes into contact attributes and queue configuration provides the basis for context-preserving bot-to-agent handoffs[^26]. ## Input handling and quotas Lex bots accept both spoken voice and DTMF keypad input[^50]. When touchtone buffering is enabled, Connect clears the buffer before the Lex interaction, ignoring pre-typed digits[^55]. DTMF input defaults to `#` as the end character, `*` as the deletion character, an inter-digit timeout of 5,000 ms, and a maximum of 1,024 digits[^16]. Callers who do not enter `#` wait 5 seconds before input ends[^15]. DTMF entries are surfaced in the `x-amz-lex:dtmf-transcript` request attribute, with deletions ending in `[DEL]`[^17]. For voice interactions, the end silence timeout defaults to 600 ms[^19]. Lex V2 enables voice barge-in by default, which can be modified per slot or via the `x-amz-lex:allow-interrupt::` attribute[^7]. For Lex Classic (V1) bots, barge-in was disabled by default and had to be enabled with the `x-amz-lex:barge-in-enabled::` session attribute in Get customer input[^6]. Lex V2 limits runtime conversation duration, audio length, and concurrency[^11][^53][^43]. | Quota | Default limit | Adjustability | | --- | --- | --- | | Single conversation duration | 15 minutes | Not adjustable[^11] | | Single audio input length | 55 seconds | Not adjustable[^11] | | TestBotAlias concurrency | 2 voice conversations | Not adjustable[^53] | | Non-test alias RecognizeUtterance concurrency | 125 voice conversations | Adjustable via support[^43] | | Non-test alias StartConversation concurrency | 400 voice conversations | Adjustable via support[^43] | | Lambda function timeout | 30 seconds | Adjustable via support[^31] | | Lambda input / output payload size | 12 KB in / 50 KB out | Not stated as adjustable[^31] | | Intents per locale (en-AU, en-GB, en-US) | 1,000 | Adjustable via support[^30] | | Intents per locale (other locales) | 250 | Adjustable via support[^30] | | Slots per intent | 100 | Not adjustable[^30] | AWS instructs that production Connect flows use an alias other than TestBotAlias (Lex V2) or $LATEST (Lex Classic), because those support only a limited number of concurrent calls to the bot[^41]. ## Language and locale configuration For Lex V2 bots, the contact's language attribute must match the bot's built locale, configured using Set voice or Set contact attributes[^56]. If a non-en-US voice is selected without enabling Set language attribute in Set voice, the Get customer input block produces an error[^42]. The Set voice block does not validate language codes, allowing invalid codes to pass through and fail later in Lex interactions[^48]. For multi-locale bots, AWS recommends assigning the `$.LanguageCode` system attribute at the start of the flow[^38]. Several Lex V2 speech features are English-only: custom vocabulary and runtime slot hints are limited to en_GB and en_US, and the grammar slot type and spelling styles to en_AU, en_GB and en_US[^20]. Locales such as af_ZA, cs_CZ, he_IL, tr_TR, and vi_VN have limited support through generative features and third-party engines, whereas nl_BE and fr_BE require third-party Deepgram ASR[^35]. Twelve Lex V2 locales, including zh_CN, zh_HK, hi_IN, pt_BR and pl_PL, are not available in the Asia Pacific (Singapore) ap-southeast-1 Region[^49]. ## Cross-Region and third-party integrations Cross-Region Lex bot associations have been supported in Connect since July 30, 2018[^12]. For multi-region deployments, Amazon Lex V2 Global Resiliency replicates bots and aliases between us-east-1/us-west-2 and eu-west-2/eu-central-1 via AWS Connect SA or TAM request[^25]. Global Resiliency does not support bots utilizing generative slot features (like CFAQ and utterance generation) or bot networks[^24]. Connect Customer instances include generative speech and agentic voice and chat self-service[^13]. All newly created Connect instances are Connect Customer instances[^39]. Third-party speech-to-text (STT) and text-to-speech (TTS) integration is exclusive to Connect Customer and unavailable in Customer Basic[^1]. Third-party STT requires setting a model ID and an AWS Secrets Manager secret ARN in the same Region as the Connect instance, followed by rebuilding the bot locale[^3]. Once configured, Connect routes runtime audio to the third party without changes to flows or Lambda functions[^2]. ## See also See also [Amazon Connect contact flows and routing profiles](https://warmtransfer.net/knowledge/amazon-connect-flows). ## Applicability Applies to: AWS Amazon Connect with Amazon Lex, AWS Amazon Lex, AWS Amazon Connect with Amazon Lex V2, AWS Amazon Connect (Connect Customer), AWS Amazon Connect, AWS Amazon Connect with Amazon Lex Classic, AWS Amazon Lex V2, AWS Amazon Lex V2 with Amazon Connect, and AWS Amazon Connect (Connect Customer) conversational AI bots. Deployments: multi-tenant. Sources checked 2026-09-25. Amazon Lex V1 support ended effective September 15, 2025[^34]. Cross-Region bot associations apply from July 30, 2018 onward[^12]. Amazon Lex V2 Global Resiliency applies exclusively to the us-east-1/us-west-2 and eu-west-2/eu-central-1 region pairs[^25]. Twelve Lex V2 locales are not available in the Asia Pacific (Singapore) ap-southeast-1 Region[^49]. Third-party STT and TTS features apply to Connect Customer instances and are not supported in Customer Basic[^1]. ## What remains uncertain The differences between Connect Customer agentic self-service AI agents and classic Lex bots in the Get customer input block are not covered by the sources below. Whether Lex requests are billed separately on Connect Customer instances or covered by per-channel pricing is not covered by the sources below. The use of Lex generative features such as Assisted NLU, assisted slot resolution, QnAIntent, or intent disambiguation from Connect is not covered by the sources below. The specific `$.Lex.*` contact attribute JSONPaths, including `IntentName`, `Slots`, `SessionAttributes`, sentiment, and alternative intents, are not covered by the sources below. Amazon Lex streaming-conversation interval pricing and generative feature pricing are not covered by the sources below. Which specific Lex runtime API Connect uses for voice, and therefore which concurrency quota binds at runtime, is not covered by the sources below. Third-party TTS providers such as ElevenLabs, along with the complete endpoint and Region list for third-party speech, are not covered by the sources below. AWS re:Post documentation regarding Lex integration failures, including same-account constraints, is not covered by the sources below. ## Sources [^1]: Third-party STT and TTS model support is listed among features available only in Connect Customer and not in Connect Customer Basic; switching an instance to Customer Basic can cause runtime errors in flows that use such features. Source: [Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/enable-nextgeneration-amazonconnect.html), sections 'Features only available in Connect Customer' (Agentic voice bullets) and 'How to switch to Customer Basic' Warning. Checked 2026-09-25. [^2]: Switching a bot locale to a third-party STT provider requires no changes to flows or Lambda functions; Connect routes the audio to the chosen provider and bot metrics continue to work. Source: [Configure third-party speech-to-text (STT) providers](https://docs.aws.amazon.com/connect/latest/adminguide/configure-third-party-stt.html), section 'Runtime behavior (STT)'. Checked 2026-09-25. [^3]: A third-party speech-to-text provider for a Connect bot locale is configured with a provider model ID and an AWS Secrets Manager secret holding the API key; the secret must be in the same Region as the Connect instance and the locale must be rebuilt before the setting takes effect. Source: [Configure third-party speech-to-text (STT) providers](https://docs.aws.amazon.com/connect/latest/adminguide/configure-third-party-stt.html), sections 'Step 5: Enter the model ID and Secrets Manager ARN' and 'Build and activate the locale'. Checked 2026-09-25. [^4]: For Lex V2 bots, the Get customer input block lets the bot alias be chosen from a dropdown or set manually as an alias ARN, either typed or supplied by a dynamic attribute; in flow language this is ConnectParticipantWithLexBot with LexV2Bot.AliasArn. Source: [Add an Amazon Lex bot to Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/amazon-lex.html), section 'Create a flow and add your Amazon Lex bot', step 7 sub-item 3. Checked 2026-09-25. [^5]: A Lex V2 bot is associated with a Connect instance in the AWS Connect console: select the instance, choose Flows, and in the Amazon Lex section pick the bot's Region, the bot, and a bot alias, then choose Add Lex Bot. Source: [Add an Amazon Lex bot to Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/amazon-lex.html), section 'Add the Amazon Lex bot to your Connect Customer instance', Amazon Lex tab, steps 1-5. Checked 2026-09-25. [^6]: For Lex Classic (V1) bots, barge-in was disabled by default and had to be enabled with the x-amz-lex:barge-in-enabled:: session attribute in Get customer input; that attribute controlled Lex barge-in only, not DTMF barge-in. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Barge-in configuration and usage for Amazon Lex', Amazon Lex (Classic) tab. Checked 2026-09-25. [^7]: For Lex V2 bots, barge-in (caller interrupting the bot prompt by voice) is enabled by default; it can be disabled per slot prompt in the Lex console or controlled with the x-amz-lex:allow-interrupt:: session attribute. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Barge-in configuration and usage for Amazon Lex', Amazon Lex tab. Checked 2026-09-25. [^8]: Conversational AI bots for IVR and chat self-service can be created and edited directly in the Connect admin website, and these bots are powered by Amazon Lex. Source: [Create conversational AI bots in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/connect-conversational-ai-bots.html), opening paragraphs. Checked 2026-09-25. [^9]: For chat contacts in a Lex interaction, the Get customer input Chat timeout can be set from 1 minute to 7 days. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), subsection 'Configurable time-outs for chat input during a Lex interaction'. Checked 2026-09-25. [^10]: The Amazon Connect pricing page lists Connect Customer voice at $0.038 per minute with standard telephony charged in addition, and chat at $0.010 per message sent or received. Source: [Amazon Connect Customer Pricing](https://aws.amazon.com/connect/pricing/), per-channel pricing section. Checked 2026-09-25. [^11]: Amazon Lex V2 caps a single conversation at 15 minutes and a single audio input at 55 seconds; neither quota is adjustable. Source: [Quotas (Amazon Lex V2 Developer Guide)](https://docs.aws.amazon.com/lexv2/latest/dg/quotas.html), 'Runtime quotas' table, rows 'Maximum duration for a single conversation' and 'Maximum audio length'. Checked 2026-09-25. [^12]: Since July 30, 2018, Amazon Connect has allowed Lex bots from any Region where Amazon Lex is available to be added to a Connect instance, and the current association UI asks for the bot's Region. Source: [Amazon Connect Now Supports Using Cross-Region Amazon Lex Bots](https://aws.amazon.com/about-aws/whats-new/2018/07/amazon-connect-now-supports-using-cross-region-amazon-lex-bots), announcement body, first sentence. Checked 2026-09-25. [^13]: AWS lists end-customer self-service (agentic voice and agentic chat powered by AI agents) and generative speech, including third-party STT/TTS configuration, as capabilities included with Connect Customer. Source: [Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/enable-nextgeneration-amazonconnect.html), section 'AI capabilities', first two bullets. Checked 2026-09-25. [^14]: The default text-to-speech voice in Amazon Connect is Joanna (Conversational speaking style), and the Lex console walkthrough notes Joanna as Connect's default when choosing the bot voice. Source: [Flow block in Connect Customer: Set voice](https://docs.aws.amazon.com/connect/latest/adminguide/set-voice.html), section 'Description', second bullet. Checked 2026-09-25. [^15]: If callers are not told to finish keypad entry with #, they wait five seconds before the Lex bot stops listening for more digits. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Additional configuration tips', bullet on # and * keys. Checked 2026-09-25. [^16]: Lex DTMF input from Connect defaults to # as end character, * as deletion character, a 5,000 ms inter-digit end timeout, and a 1,024-digit per-utterance maximum that cannot be increased. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), subsection 'Configurable fields for DTMF input'. Checked 2026-09-25. [^17]: DTMF input passed from Connect to a Lex bot is exposed to the bot as the request attribute x-amz-lex:dtmf-transcript, up to 1,024 characters; input ending with the deletion character yields a transcript of [DEL]. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Additional configuration tips', last bullet and DTMF transcript table. Checked 2026-09-25. [^18]: In-Connect bot building is enabled per instance in the AWS console under Flows by selecting 'Enable Lex Bot Management' and 'Enable Bot Analytics and Transcripts', and users then need the security profile permissions Channels and Flows > Bots (View, Edit, Create) and Analytics and Optimization > Historical metrics (Access). Source: [Enable bot building and analytics in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/enable-bot-building.html), steps 3-5. Checked 2026-09-25. [^19]: The Lex V2 end silence threshold x-amz-lex:audio:end-timeout-ms, which decides when a caller's utterance is complete, defaults to 600 ms. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), subsection 'Configurable time-outs for voice input', Amazon Lex tab, 'End Silence Threshold'. Checked 2026-09-25. [^20]: Several Lex V2 speech features are English-only: custom vocabulary and runtime slot hints are limited to en_GB and en_US, and the grammar slot type and spelling styles to en_AU, en_GB and en_US. Source: [Languages and locales supported by Amazon Lex V2](https://docs.aws.amazon.com/lexv2/latest/dg/how-languages.html), 'Languages and locales supported by Amazon Lex V2 features' table rows for custom vocabulary, runtime hints, grammar slot type, spelling styles. Checked 2026-09-25. [^21]: In Lex mode, Get customer input routes to the matching intent branch; Default fires when no configured intent matches, Error fires when the intent is not fulfilled, and Timeout fires on the configured chat timeout. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Flow block branches', items 1-3. Checked 2026-09-25. [^22]: The Get customer input block supports voice contacts, supports chat only when an Amazon Lex bot is used (otherwise chat takes the Error branch), and does not support task or email contacts. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Contact types' table. Checked 2026-09-25. [^23]: Get customer input, and therefore a Lex bot invocation, cannot be used in customer hold, customer whisper, agent hold or agent whisper flows; it is supported in inbound, customer queue, outbound whisper, transfer to agent and transfer to queue flows. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Flow types' table. Checked 2026-09-25. [^24]: Lex V2 Global Resiliency does not replicate bots that use LLM-based slot features such as CFAQ and utterance generation, and does not replicate a Network of Bots as a unit. Source: [Use Global Resiliency to deploy bots to other Regions](https://docs.aws.amazon.com/lexv2/latest/dg/global-resiliency.html), 'Limitations' bullets. Checked 2026-09-25. [^25]: Amazon Lex V2 Global Resiliency, which replicates bots, versions and aliases to a paired Region, is available only for Connect and Lex V2 in the pairs us-east-1/us-west-2 and eu-west-2/eu-central-1, and access is obtained through an AWS Connect Solutions Architect or TAM. Source: [Use Global Resiliency to deploy bots to other Regions](https://docs.aws.amazon.com/lexv2/latest/dg/global-resiliency.html), first Note and region-pair table. Checked 2026-09-25. [^26]: Because Lex session attributes are readable by Set contact attributes and Set working queue, a flow can carry values collected by the bot into contact attributes and queue selection before transferring to an agent, which is the documented basis for context-preserving bot-to-agent handoff (inferred). Source: [How flow blocks use Amazon Lex session attributes](https://docs.aws.amazon.com/connect/latest/adminguide/how-to-use-session-attributes.html), section 'Flow blocks that support Lex session attributes' combined with aws-connect-add-lex-bot 'Finish the flow'. Checked 2026-09-25. [^27]: AWS's reference walkthrough hands a caller to an agent by wiring the bot's SpeakToAgent intent branch from Get customer input to a Set working queue block followed by a Transfer to queue block. Source: [Add an Amazon Lex bot to Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/amazon-lex.html), subsection 'Finish the flow', 'To complete the SpeakToAgent intent' steps. Checked 2026-09-25. [^28]: For chat, Get customer input can initialise the Lex bot with the customer's first message or a manual or dynamic message of up to 1,024 characters; if the initial message attribute is absent from the contact, the contact goes down the Error branch. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Configure for Amazon Lex input', 'Initialize bot with message' bullets and following Note. Checked 2026-09-25. [^29]: The Get customer input Intents dropdown does not list intents for Lex V1 bots, cross-Region bots, or bots whose ARN is set dynamically; listing requires the bot to carry the AmazonConnectEnabled=True tag and the alias to have an associated version. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Configure for Amazon Lex input', 'Intents' > 'Add intent' bullets. Checked 2026-09-25. [^30]: A Lex V2 bot locale may hold up to 1,000 intents in en-AU, en-GB and en-US and 250 in all other locales by default (adjustable, not self-service), with at most 100 slots per intent (not adjustable). Source: [Quotas (Amazon Lex V2 Developer Guide)](https://docs.aws.amazon.com/lexv2/latest/dg/quotas.html), 'Build-time quotas' table, rows 'Intents per locale in each bot' and 'Slots per intent'. Checked 2026-09-25. [^31]: A Lambda code hook invoked by an Amazon Lex V2 bot has a maximum timeout of 30 seconds by default (adjustable via support, not self-service), with a 12 KB input limit and 50 KB output limit. Source: [Quotas (Amazon Lex V2 Developer Guide)](https://docs.aws.amazon.com/lexv2/latest/dg/quotas.html), 'Runtime quotas' table, rows 'Maximum timeout of a Lambda function', 'Maximum input size to a Lambda function', 'Maximum output size of a Lambda function'. Checked 2026-09-25. [^32]: Lex session attributes can be referenced in routing-related flow blocks including Set working queue, Change routing priority / age, Transfer to flow, Transfer to phone number, Check contact attributes and Set contact attributes. Source: [How flow blocks use Amazon Lex session attributes](https://docs.aws.amazon.com/connect/latest/adminguide/how-to-use-session-attributes.html), section 'Flow blocks that support Lex session attributes'. Checked 2026-09-25. [^33]: Amazon Lex list pricing for request-and-response interactions is $0.004 per speech request and $0.00075 per text request. Source: [Amazon Lex Pricing](https://aws.amazon.com/lex/pricing/), section 'Request and response interaction' pricing. Checked 2026-09-25. [^34]: AWS ended support for Amazon Lex V1 on September 15, 2025; after that date the Lex V1 console and Lex V1 resources are no longer accessible, and AWS directs customers to migrate to Amazon Lex V2. Source: [Add an Amazon Lex bot to Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/amazon-lex.html), 'Important - End of support notice' banner at top of page. Checked 2026-09-25. [^35]: Amazon Lex V2 marks many locales (for example af_ZA, cs_CZ, he_IL, tr_TR, vi_VN) with an asterisk meaning limited feature support via generative AI and third-party ASR or TTS, and nl_BE and fr_BE are supported only with third-party ASR (Deepgram). Source: [Languages and locales supported by Amazon Lex V2](https://docs.aws.amazon.com/lexv2/latest/dg/how-languages.html), 'Supported languages and locales' table footnote and 'Languages and locales supported by Amazon Lex V2 features' rows 'Only with Third-party ASR (Deepgram)'. Checked 2026-09-25. [^36]: The Connect Get customer input page states that for Lex V2 the max speech duration attribute x-amz-lex:audio:max-length-ms defaults to 12,000 ms, has a maximum of 55,000 ms, and that setting it above 55,000 ms routes the contact down the Error branch (disputed). Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), subsection 'Configurable time-outs for voice input', Amazon Lex tab, 'Max Speech Duration'. Checked 2026-09-25. [^37]: The Amazon Lex V2 Developer Guide states x-amz-lex:audio:max-length-ms defaults to 55,000 ms with a 55,000 ms maximum, and that a value above 55,000 ms falls back to 55,000 ms (disputed). Source: [Configuring timeouts for capturing user input with a Lex V2 bot](https://docs.aws.amazon.com/lexv2/latest/dg/session-attribs-speech.html), section 'Set the timeouts for voice input' > 'Maximum utterance length'. Checked 2026-09-25. [^38]: For a single Lex bot serving multiple locales, AWS recommends a Set contact attributes block at the start of the flow configured with the $.LanguageCode system attribute. Source: [Add an Amazon Lex bot to Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/amazon-lex.html), 'Tip' at end of subsection 'Finish the flow'. Checked 2026-09-25. [^39]: All newly created Amazon Connect instances are Connect Customer instances; older instances may need to be updated to Connect Customer from the instance's Connect Customer page in the AWS console. Source: [Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/enable-nextgeneration-amazonconnect.html), section 'Updating an existing instance to Connect Customer'. Checked 2026-09-25. [^40]: Lex V1 bots and cross-Region bots cannot be edited from within the Connect admin website. Source: [Enable bot building and analytics in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/enable-bot-building.html), second paragraph, before step 1. Checked 2026-09-25. [^41]: AWS instructs that production Connect flows use an alias other than TestBotAlias (Lex V2) or $LATEST (Lex Classic), because those support only a limited number of concurrent calls to the bot. Source: [Add an Amazon Lex bot to Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/amazon-lex.html), 'Important' box in section 'Create an alias for the bot'. Checked 2026-09-25. [^42]: If a flow uses a non-en-US voice with a Lex V2 bot and Set language attribute is not chosen in the Set voice block, the Get customer input block results in an error. Source: [Flow block in Connect Customer: Set voice](https://docs.aws.amazon.com/connect/latest/adminguide/set-voice.html), section 'Use an Amazon Lex V2 bot with Connect Customer', second bullet. Checked 2026-09-25. [^43]: For Lex V2 aliases other than TestBotAlias, the default concurrent voice-mode conversation quota is 125 for RecognizeUtterance and 400 for StartConversation; both are adjustable but not through self-service. Source: [Quotas (Amazon Lex V2 Developer Guide)](https://docs.aws.amazon.com/lexv2/latest/dg/quotas.html), 'Runtime quotas' table, rows 'Maximum number of concurrent voice-mode conversations ... for other aliases'. Checked 2026-09-25. [^44]: When a Lex V2 bot is associated with a Connect instance, Connect updates the bot's Amazon Lex resource-based policy to grant Connect permission to invoke the bot. Source: [Add an Amazon Lex bot to Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/amazon-lex.html), Note under 'Add the Amazon Lex bot to your Connect Customer instance', Amazon Lex tab. Checked 2026-09-25. [^45]: Service control policies that already block Lex prevent Connect from enabling bot management and analytics, but SCPs added after the feature is enabled are not respected, so the feature must be disabled manually in that case. Source: [Enable bot building and analytics in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/enable-bot-building.html), Note under step 4. Checked 2026-09-25. [^46]: Get customer input can branch on Lex sentiment before intent matching; the score is based only on the customer's last utterance, and if both negative and positive thresholds are set the negative one is evaluated first. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Configure for Amazon Lex input', 'Use sentiment override' bullet. Checked 2026-09-25. [^47]: Each Lex conversation from Connect has one set of session attributes; values set by a Lambda code hook override those set in the Get customer input block, which in turn override service defaults. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Additional configuration tips', bullet on order of precedence. Checked 2026-09-25. [^48]: The Set voice block does not validate the language code it is given, so an invalid code does not take the Error branch in that block but can cause erroneous behaviour later with Lex V2 bots. Source: [Flow block in Connect Customer: Set voice](https://docs.aws.amazon.com/connect/latest/adminguide/set-voice.html), 'Tip' box in section 'Properties' and row 'ar-AE / Ruth' of the 'Configuration Examples' table. Checked 2026-09-25. [^49]: Twelve Lex V2 locales, including zh_CN, zh_HK, hi_IN, pt_BR and pl_PL, are not available in the Asia Pacific (Singapore) ap-southeast-1 Region. Source: [Languages and locales supported by Amazon Lex V2](https://docs.aws.amazon.com/lexv2/latest/dg/how-languages.html), 'Languages and locales supported by Amazon Lex V2 features' table, row 'Region availability'. Checked 2026-09-25. [^50]: Amazon Lex bots invoked from an Amazon Connect flow accept both spoken utterances and keypad (DTMF) input, so callers can choose to key sensitive values such as account numbers instead of speaking them. Source: [Add an Amazon Lex bot to Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/amazon-lex.html), introductory paragraphs before 'Create an Amazon Lex bot'. Checked 2026-09-25. [^51]: The Connect Get customer input page states the Lex V2 start silence threshold x-amz-lex:audio:start-timeout-ms defaults to 3,000 ms (disputed). Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), subsection 'Configurable time-outs for voice input', Amazon Lex tab, 'Start Silence Threshold'. Checked 2026-09-25. [^52]: The Amazon Lex V2 Developer Guide states the voice timeout x-amz-lex:audio:start-timeout-ms defaults to 4,000 ms (disputed). Source: [Configuring timeouts for capturing user input with a Lex V2 bot](https://docs.aws.amazon.com/lexv2/latest/dg/session-attribs-speech.html), section 'Set the timeouts for voice input' > 'Voice timeout'. Checked 2026-09-25. [^53]: Amazon Lex V2 limits the TestBotAlias to 2 concurrent voice-mode conversations for both RecognizeUtterance and StartConversation, and this quota is not adjustable. Source: [Quotas (Amazon Lex V2 Developer Guide)](https://docs.aws.amazon.com/lexv2/latest/dg/quotas.html), 'Runtime quotas' table, rows 'Maximum number of concurrent voice-mode conversations ... for the TestBotAlias'. Checked 2026-09-25. [^54]: Text-to-speech or chat text prompts in Get customer input are limited to 3,000 billed characters (6,000 total characters). Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Additional configuration tips', first sub-bullet on session attributes. Checked 2026-09-25. [^55]: When touchtone buffering is enabled, Get customer input in Amazon Lex mode clears the buffer before the bot interaction, so digits typed ahead are not passed to the bot. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Touchtone buffering', second bullet. Checked 2026-09-25. [^56]: With a Lex V2 bot, the Connect contact's language attribute must match the locale the bot was built with; this differs from Lex Classic, and the language is set with the Set voice block (Set language attribute) or a Set contact attributes block. Source: [Add an Amazon Lex bot to Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/amazon-lex.html), 'Important' box at start of section 'Create a flow and add your Amazon Lex bot'. Checked 2026-09-25. [^57]: Lex session attribute keys set in Get customer input accept * wildcards for intent and slot, and wildcard settings apply across bots but not across other Get customer input blocks in the same flow. Source: [Flow block in Connect Customer: Get customer input](https://docs.aws.amazon.com/connect/latest/adminguide/get-customer-input.html), section 'Additional configuration tips', wildcard bullet and Get_Account_Number example. Checked 2026-09-25.