# Telnyx Fundamentals: Development — Documentation Index
> Development documentation within the Fundamentals section of the Telnyx developer docs (https://developers.telnyx.com).
> This file: https://developers.telnyx.com/docs/development/llms-txt · Root index: https://developers.telnyx.com/llms.txt

- [Overview](https://developers.telnyx.com/docs/development.md): Essential tools, SDKs, and resources for building with Telnyx APIs and services.

## Account setup

- [Create Account](https://developers.telnyx.com/docs/account-setup/create-account.md): Step-by-step guide to create and set up your Telnyx account for accessing APIs and services.
- [Account Signup](https://developers.telnyx.com/docs/account-setup/signup.md): Understand the trust and safety checks applied to every Telnyx signup attempt.
- [Account Levels Overview](https://developers.telnyx.com/docs/account-setup/levels-and-capabilities.md): Understand how Telnyx accounts are categorized and what distinguishes each framework.
- [Pretrial Account](https://developers.telnyx.com/docs/account-setup/levels-and-capabilities/pretrial.md): Capabilities, restrictions, and daily limits applied to Telnyx pretrial accounts.
- [Trial Account](https://developers.telnyx.com/docs/account-setup/levels-and-capabilities/trial.md): Capabilities, restrictions, and daily limits applied to Telnyx trial accounts.
- [Using Your Trial Account](https://developers.telnyx.com/docs/account-setup/using-trial-account.md): Recommended process to get the most value from Telnyx trial credits.
- [Paid Account](https://developers.telnyx.com/docs/account-setup/levels-and-capabilities/paid.md): Capabilities and restrictions for paid Telnyx accounts — expanded number purchasing, messaging throughput, and product access beyond trial accounts.
- [Verified Account](https://developers.telnyx.com/docs/account-setup/levels-and-capabilities/verified.md): Capabilities that remain restricted after verification and how to request enterprise access.
- [Account Upgrade](https://developers.telnyx.com/docs/account-setup/account-upgrade.md): Actions required to advance from pretrial to trial, paid, verified, and enterprise Telnyx accounts.
- [Data Locality](https://developers.telnyx.com/docs/account-setup/data-locality.md): Choose where your Telnyx data is stored at rest. Available regions are the US, Germany (EU), Australia, and UAE.

## API fundamentals

- [Overview](https://developers.telnyx.com/docs/development/api-fundamentals.md): Authenticate, make a first request, handle responses and failures, and operate Telnyx REST API integrations reliably.
- [Create API keys](https://developers.telnyx.com/docs/development/api-fundamentals/create-api-keys.md): Create, store, rotate, and revoke Telnyx server-side API credentials.
- [Make the first request](https://developers.telnyx.com/docs/development/api-fundamentals/first-api-request.md): Validate a Telnyx API key with a safe, read-only account balance request.
- [Authentication](https://developers.telnyx.com/docs/development/api-fundamentals/authentication.md): Authenticate server-side Telnyx REST API requests with Bearer API keys and identify product-specific alternatives.
- [Requests and responses](https://developers.telnyx.com/docs/development/api-fundamentals/request-response.md): Construct Telnyx REST API requests and interpret endpoint-specific success and error responses.
- [Pagination and filtering](https://developers.telnyx.com/docs/development/api-fundamentals/pagination-filtering-sorting.md): Traverse Telnyx REST API collections using endpoint-supported pagination, filter, and sort parameters.
- [API error catalog](https://developers.telnyx.com/docs/development/api-fundamentals/api-errors.md): Telnyx API error codes, product-specific references, and the unified machine-readable error catalog.
- [Rate limiting](https://developers.telnyx.com/docs/development/api-fundamentals/reliability/rate-limiting.md): Detect Telnyx REST API rate limits and recover from 429 responses without creating retry bursts.
- [Retries and reliability](https://developers.telnyx.com/docs/development/api-fundamentals/reliability/command-retries.md): Retry Telnyx REST API operations safely using bounded backoff, jitter, and operation-specific idempotency controls.
- [Webhook fundamentals](https://developers.telnyx.com/docs/development/api-fundamentals/webhooks/receiving-webhooks.md): Verify Telnyx webhook signatures, acknowledge deliveries promptly, and process duplicate or out-of-order events safely.
- [Parameters and fields](https://developers.telnyx.com/docs/development/api-fundamentals/data-standards/parameters-fields.md): Common Telnyx REST API value formats and naming conventions, subject to each endpoint schema.
- [Versions and deprecations](https://developers.telnyx.com/docs/development/api-fundamentals/api-versions.md): Identify Telnyx API versions, follow endpoint-specific lifecycle notices, and plan migrations away from retired interfaces.
- [Other interfaces](https://developers.telnyx.com/docs/development/api-fundamentals/legacy-apis.md): Distinguish active product-specific interfaces from retired Telnyx HTTP APIs outside the V2 REST contract.
- [Troubleshooting](https://developers.telnyx.com/docs/development/api-fundamentals/troubleshooting.md): Diagnose Telnyx REST API authentication, authorization, validation, throttling, and transient service failures.

## Server-side SDKs

- [Overview](https://developers.telnyx.com/docs/development/sdk.md): Choose and install an official Telnyx SDK for TypeScript and Node.js, Python, Go, Java, Ruby, or PHP.
- [Overview and quickstart](https://developers.telnyx.com/docs/development/sdk/node.md): Install and use the official Telnyx TypeScript and Node.js SDK with typed requests, pagination, retries, timeouts, and structured errors.
- [Requests, types, and pagination](https://developers.telnyx.com/docs/development/sdk/node/requests-and-types.md): Request and response types, file uploads, and automatic pagination.
- [Resource map](https://developers.telnyx.com/docs/development/sdk/node/resource-map.md): High-level map of every Telnyx Node.js SDK resource and method, with the REST endpoint each method calls.
- [Errors and retries](https://developers.telnyx.com/docs/development/sdk/node/errors-and-retries.md): Error classes, automatic retry behavior, and timeout configuration in the Telnyx Node.js SDK.
- [Webhooks](https://developers.telnyx.com/docs/development/sdk/node/webhooks.md): Verify Telnyx ED25519 webhook signatures and parse typed webhook events with the Node.js SDK.
- [Advanced](https://developers.telnyx.com/docs/development/sdk/node/advanced.md): File uploads, raw response access, custom requests, FAQ, versioning, and requirements for the Telnyx Node.js SDK.
- [Overview and quickstart](https://developers.telnyx.com/docs/development/sdk/python.md): Install and use the official Telnyx Python SDK with sync and async clients, typed models, pagination, retries, and timeouts.
- [Requests, types, and pagination](https://developers.telnyx.com/docs/development/sdk/python/requests-and-types.md): Typed models, nested parameters, file uploads, and pagination.
- [Resource map](https://developers.telnyx.com/docs/development/sdk/python/resource-map.md): High-level map of every Telnyx Python SDK resource and method, with the REST endpoint each method calls.
- [Errors and retries](https://developers.telnyx.com/docs/development/sdk/python/errors-and-retries.md): Exception hierarchy, automatic retry behavior, and timeout configuration in the Telnyx Python SDK.
- [Webhooks](https://developers.telnyx.com/docs/development/sdk/python/webhooks.md): Verify Telnyx ED25519 webhook signatures and parse typed webhook events with the Python SDK.
- [Advanced](https://developers.telnyx.com/docs/development/sdk/python/advanced.md): Logging, raw response access, undocumented requests, custom HTTP clients, versioning, and requirements for the Telnyx Python SDK.
- [Overview and quickstart](https://developers.telnyx.com/docs/development/sdk/golang.md): Install and use the official Telnyx Go SDK with typed requests, response models, pagination, retries, and request options.
- [Requests, types, and pagination](https://developers.telnyx.com/docs/development/sdk/golang/requests-and-types.md): Request fields and unions, response models, options, uploads, and pagination.
- [Resource map](https://developers.telnyx.com/docs/development/sdk/golang/resource-map.md): High-level map of every Telnyx Go SDK service and method, with the REST endpoint each method calls.
- [Errors and retries](https://developers.telnyx.com/docs/development/sdk/golang/errors-and-retries.md): Error types, automatic retry behavior, and timeout configuration in the Telnyx Go SDK.
- [Webhooks](https://developers.telnyx.com/docs/development/sdk/golang/webhooks.md): Verify Telnyx ED25519 webhook signatures and parse typed webhook events with the Go SDK.
- [Advanced](https://developers.telnyx.com/docs/development/sdk/golang/advanced.md): Raw response access, custom requests, middleware, versioning, and requirements for the Telnyx Go SDK.
- [Overview and quickstart](https://developers.telnyx.com/docs/development/sdk/java.md): Install and use the official Telnyx Java SDK with synchronous and asynchronous clients, immutable models, pagination, retries, and timeouts.
- [Requests, types, and pagination](https://developers.telnyx.com/docs/development/sdk/java/requests-and-types.md): Immutable request and response models, uploads, raw responses, and pagination.
- [Resource map](https://developers.telnyx.com/docs/development/sdk/java/resource-map.md): High-level map of every Telnyx Java SDK resource and method, with the REST endpoint each method calls.
- [Errors and retries](https://developers.telnyx.com/docs/development/sdk/java/errors-and-retries.md): Exception hierarchy and network options — retries, timeouts, and proxies — in the Telnyx Java SDK.
- [Webhooks](https://developers.telnyx.com/docs/development/sdk/java/webhooks.md): Verify Telnyx ED25519 webhook signatures and parse typed webhook events with the Java SDK.
- [Advanced](https://developers.telnyx.com/docs/development/sdk/java/advanced.md): Logging, ProGuard and R8, Jackson, undocumented API functionality, FAQ, and versioning for the Telnyx Java SDK.
- [Overview and quickstart](https://developers.telnyx.com/docs/development/sdk/ruby.md): Install and use the official Telnyx Ruby SDK with typed models, pagination, retries, timeouts, file uploads, and Sorbet types.
- [Requests, types, and pagination](https://developers.telnyx.com/docs/development/sdk/ruby/requests-and-types.md): Models, Sorbet types, file uploads, and pagination.
- [Resource map](https://developers.telnyx.com/docs/development/sdk/ruby/resource-map.md): High-level map of every Telnyx Ruby SDK resource and method, with the REST endpoint each method calls.
- [Errors and retries](https://developers.telnyx.com/docs/development/sdk/ruby/errors-and-retries.md): Error classes, automatic retry behavior, and timeout configuration in the Telnyx Ruby SDK.
- [Webhooks](https://developers.telnyx.com/docs/development/sdk/ruby/webhooks.md): Verify Telnyx ED25519 webhook signatures and parse typed webhook events with the Ruby SDK.
- [Advanced](https://developers.telnyx.com/docs/development/sdk/ruby/advanced.md): Advanced concepts, Sorbet types, versioning, and requirements for the Telnyx Ruby SDK.
- [Overview and quickstart](https://developers.telnyx.com/docs/development/sdk/php.md): Install and use the official Telnyx PHP SDK with value objects, named parameters, pagination, retries, and file uploads.
- [Requests, types, and pagination](https://developers.telnyx.com/docs/development/sdk/php/requests-and-types.md): Value objects, file uploads, and pagination.
- [Resource map](https://developers.telnyx.com/docs/development/sdk/php/resource-map.md): High-level map of every Telnyx PHP SDK resource and method, with the REST endpoint each method calls.
- [Errors and retries](https://developers.telnyx.com/docs/development/sdk/php/errors-and-retries.md): Exception classes and automatic retry behavior in the Telnyx PHP SDK.
- [Webhooks](https://developers.telnyx.com/docs/development/sdk/php/webhooks.md): Verify Telnyx ED25519 webhook signatures and parse typed webhook events with the PHP SDK.
- [Advanced](https://developers.telnyx.com/docs/development/sdk/php/advanced.md): Response data access, SSL/TLS compatibility and configuration, development workflow, and plugin development for the Telnyx PHP SDK.

## Telnyx CLI

- [Overview](https://developers.telnyx.com/docs/development/cli.md): The Telnyx CLI is the official command-line interface for managing phone numbers, messaging, calls, and other Telnyx resources from your terminal.
- [Install](https://developers.telnyx.com/docs/development/cli/getting-started/install.md): Install the Telnyx CLI on macOS, Windows, or Linux using Homebrew, the install script, or by downloading a prebuilt binary for your platform.
- [Quickstart](https://developers.telnyx.com/docs/development/cli/getting-started/quickstart.md): Install the Telnyx CLI, configure authentication, and run your first command in five minutes — send a message, list numbers, or place a call.
- [Authentication](https://developers.telnyx.com/docs/development/cli/getting-started/authentication.md): Authenticate the Telnyx CLI by setting the TELNYX_API_KEY environment variable so commands can call Telnyx APIs on your account's behalf.
- [Scripting & Automation](https://developers.telnyx.com/docs/development/cli/general-usage.md): Automate workflows with the Telnyx CLI using output formats, filtering, and JSON parsing — patterns for shell scripts, cron jobs, and CI/CD pipelines.
- [Command Reference](https://developers.telnyx.com/docs/development/cli/reference.md): Comprehensive reference for every Telnyx CLI command, auto-generated from the Telnyx REST API with options, examples, and per-resource usage notes.
- [10DLC Registration](https://developers.telnyx.com/docs/development/cli/workflows/10dlc.md): Register your business for US A2P 10DLC messaging using the Telnyx CLI, from brand creation through campaign approval, with copy-paste shell commands.
- [Troubleshooting](https://developers.telnyx.com/docs/development/cli/troubleshooting.md): Troubleshoot common Telnyx CLI errors including authentication failures, missing API keys, and request errors, with solutions mapped to API error codes.
- [Agent CLI](https://developers.telnyx.com/docs/development/cli/agent-cli.md): The Telnyx Agent CLI (@telnyx/agent-cli) provides composite setup commands that take you from an API key to a working capability — SMS, voice, an AI assistant on a phone number — in a single command.
- [Overview](https://developers.telnyx.com/docs/development/cli/legacy.md): Documentation for the deprecated @telnyx/api-cli Node.js package. For new projects use the current Telnyx CLI with simpler authentication.
- [Installation](https://developers.telnyx.com/docs/development/cli/legacy/install.md): Install the deprecated @telnyx/api-cli Node.js CLI for legacy projects. New projects should use the current Telnyx CLI for better support.
- [Authentication](https://developers.telnyx.com/docs/development/cli/legacy/authentication.md): Configure API keys and switch between multiple authentication profiles in the deprecated @telnyx/api-cli legacy Node.js CLI.
- [Command Reference](https://developers.telnyx.com/docs/development/cli/legacy/reference.md): Complete command reference for the deprecated @telnyx/api-cli Node.js CLI, retained for legacy projects. New projects should use the current Telnyx CLI.

## Migration Guides

- [Call Control Migration](https://developers.telnyx.com/docs/development/migration/call-control-migration-guide.md): Migrate from Telnyx Call Control v1 to v2 — endpoint differences, payload changes, webhook updates, and step-by-step tips for porting your code.
- [Messaging Migration](https://developers.telnyx.com/docs/development/migration/messaging-migration-guide.md): Migrate from Telnyx Messaging API v1 to v2 — endpoint differences, payload changes, webhook updates, and step-by-step tips for porting your code.
- [Twilio Migration](https://developers.telnyx.com/docs/development/migration/twilio-migration-guide.md): Telnyx's Programmable Fax system for migrating from Twilio. Start building on Telnyx today.

## For AI Agents

- [Agent-readable docs](https://developers.telnyx.com/docs/development/agent-readable-documentation.md): Canonical Telnyx documentation resources for AI coding agents, including clean Markdown, OpenAPI, error catalogs, webhook payloads, and seven-language endpoint samples.
- [Telnyx Local MCP Server](https://developers.telnyx.com/docs/development/mcp/local-mcp.md): Run the Telnyx Local Model Context Protocol (MCP) server to integrate Telnyx APIs with Claude Desktop and other AI assistants for agentic workflows.
- [Telnyx Remote MCP](https://developers.telnyx.com/docs/development/mcp/remote-mcp.md): Integrate Telnyx with Claude and other AI assistants using the hosted Telnyx Remote MCP server — no local MCP process required. Quick setup with API keys.