# SimpleSMS ยท SMS for Developers > The SMS API for developers: send and receive texts, verify phone numbers, > and provision real US and Canada numbers with one REST API. > Sandbox keys are free and instant; every endpoint works in test mode. Base URL: https://api.joinsimplesms.com/v1 Auth: Authorization: Bearer ssms_sk_test_... (free sandbox keys, instant) Console: https://joinsimplesms.com/console ## Authentication - [How to get and handle credentials (agents start here)](https://joinsimplesms.com/auth.md) ## Markdown twins of site pages - [Landing (Markdown)](https://joinsimplesms.com/index.md) - [Agents page (Markdown)](https://joinsimplesms.com/agents.md) - [Pricing (Markdown)](https://joinsimplesms.com/pricing.md) - **Per-tool pages** - append .md to any tool page, e.g. https://joinsimplesms.com/claude-code.md - Every page also supports `Accept: text/markdown` content negotiation. ## Documentation - [Docs index](https://joinsimplesms.com/docs/llms.txt) - [Full documentation (single file)](https://joinsimplesms.com/docs/llms-full.txt) - [Everything on this site in one file](https://joinsimplesms.com/llms-full.txt) - [Quickstart](https://joinsimplesms.com/docs/quickstart.md): Send your first SMS in under five minutes. - [Authentication](https://joinsimplesms.com/docs/authentication.md): API keys, test vs live mode, and key rotation. - [Sandbox & test numbers](https://joinsimplesms.com/docs/sandbox.md): How test mode works, including magic numbers. - [Messages](https://joinsimplesms.com/docs/messages.md): Send SMS, retrieve messages, and list history. - [Verify](https://joinsimplesms.com/docs/verify.md): Phone verification (OTP) in two API calls. - [Webhooks](https://joinsimplesms.com/docs/webhooks.md): Signed event delivery to your endpoint, with automatic retries. - [Migrate from Twilio Verify](https://joinsimplesms.com/docs/migrate-from-twilio.md): Line-by-line mapping from Twilio Verify to SimpleSMS Verify. - [Numbers](https://joinsimplesms.com/docs/numbers.md): Search, buy, organize, and release phone numbers, one at a time or hundreds at once. - [Customers](https://joinsimplesms.com/docs/customers.md): Attribute numbers, messages, verifications and usage to the businesses you send for. - [Lookup](https://joinsimplesms.com/docs/lookup.md): Carrier and line type for any number. - [Inbox & conversations](https://joinsimplesms.com/docs/inbox.md): Threaded conversations, unread counts, and the shared team inbox. - [Contacts](https://joinsimplesms.com/docs/contacts.md): Contacts, CSV import, segments and subscription topics: in the console and the API. - [Teams](https://joinsimplesms.com/docs/teams.md): Multiple users on one account: roles, email invitations, signatures. - [Batches & broadcasts](https://joinsimplesms.com/docs/broadcasts.md): One message to up to 10,000 people - from a CSV, the API, or tagged contacts - with per-recipient variables, pause, cancel and retry. - [Scheduled messages](https://joinsimplesms.com/docs/scheduled.md): Send later: schedule 1:1 messages up to 30 days out. - [Automations](https://joinsimplesms.com/docs/automations.md): Send events from your app; SimpleSMS sends, waits, and branches. - [Auto-replies & office hours](https://joinsimplesms.com/docs/auto-reply.md): Per-number automatic replies, optionally only outside business hours. - [Number porting](https://joinsimplesms.com/docs/porting.md): Bring an existing business number to SimpleSMS. - [Opt-out, consent & TCPA](https://joinsimplesms.com/docs/opt-out.md): Revocation in plain English, the consent ledger, and what is blocked. - [Compliance & registration](https://joinsimplesms.com/docs/compliance.md): Website disclosure check, generated opt-in copy, 10DLC brand and campaign registration, and opt-in proof. - [Security best practices](https://joinsimplesms.com/docs/security.md): Protect your account, API keys, and users: key hygiene, phishing awareness, and how we handle your data. - [Deliverability](https://joinsimplesms.com/docs/deliverability.md): Delivery rates by day, carrier, and sending number, plus automatic degradation alerts. - [Spend limits](https://joinsimplesms.com/docs/spend-limits.md): A monthly cap on live messaging spend, with alerts as you approach it. - [Audit log](https://joinsimplesms.com/docs/audit-logs.md): Who changed keys, team, webhooks, spend limits, numbers, consent, and settings. - [Errors](https://joinsimplesms.com/docs/errors.md): The error envelope and every error code. - [Pricing](https://joinsimplesms.com/docs/pricing.md): What SimpleSMS costs, and what the free tier includes. - [Changelog](https://joinsimplesms.com/docs/changelog.md): What changed in SimpleSMS. ## Migrating from another provider - [Migration index](https://joinsimplesms.com/migrate.md) ## Command line tool - **CLI**: `npx joinsimplesms`. Send, verify, numbers, lookup, events from the terminal; --json for scripts and agents; key via SIMPLESMS_API_KEY or `simplesms login` ## SDKs - **Node.js / TypeScript**: `npm install joinsimplesms`. Zero dependencies, works on Node 18+, Bun, Deno, Workers and Edge; ships the CLI as its bin ## OpenAPI spec - [OpenAPI spec (YAML)](https://joinsimplesms.com/openapi.yaml) - [OpenAPI spec (JSON)](https://joinsimplesms.com/openapi.json) - Also served from the API host at https://api.joinsimplesms.com/v1/openapi.yaml and https://api.joinsimplesms.com/v1/openapi.json ## MCP Server - [Streamable HTTP MCP server](https://joinsimplesms.com/api/mcp): send/receive SMS, numbers, lookup, and events as MCP tools; authenticate with your API key - [MCP Discovery](https://joinsimplesms.com/.well-known/mcp.json) ## Skills - **Install**: `curl -sSL https://joinsimplesms.com/skills/install.sh | sh` (drops the three SKILL.md files into .claude/skills; set SKILLS_DIR for another location). Works with Claude Code, Cursor, Codex, Devin, Copilot - [Skills Discovery](https://joinsimplesms.com/.well-known/agent-skills/index.json) - [simplesms](https://joinsimplesms.com/skills/simplesms/SKILL.md): send and receive SMS, get numbers - [simplesms-verify](https://joinsimplesms.com/skills/simplesms-verify/SKILL.md): phone verification (OTP/2FA) in two calls - [sms-best-practices](https://joinsimplesms.com/skills/sms-best-practices/SKILL.md): consent, opt-out, segments, 10DLC ## For AI agents - [Agents overview](https://joinsimplesms.com/agents): phone numbers, SMS inboxes, and verification for agents - [Use SimpleSMS with Claude](https://joinsimplesms.com/claude) - [Use SimpleSMS with Claude Code](https://joinsimplesms.com/claude-code) - [Use SimpleSMS with Cursor](https://joinsimplesms.com/cursor) - [Use SimpleSMS with Codex](https://joinsimplesms.com/codex) - [Use SimpleSMS with Devin](https://joinsimplesms.com/devin) - [Use SimpleSMS with GitHub Copilot](https://joinsimplesms.com/copilot) ## Changelog - [Changelog (Markdown)](https://joinsimplesms.com/changelog.md) - [Changelog (HTML)](https://joinsimplesms.com/docs/changelog) ## Legal - [Terms of Service](https://joinsimplesms.com/terms.md): The agreement for using SimpleSMS: accounts, billing, carrier charges, liability, and disputes. HTML at https://joinsimplesms.com/terms - [Messaging Policy](https://joinsimplesms.com/messaging-policy.md): Our acceptable use policy: consent, opt-outs, quiet hours, and prohibited and restricted content. HTML at https://joinsimplesms.com/messaging-policy - [Privacy Policy](https://joinsimplesms.com/privacy.md): What we collect, how we use it, how AI touches message content, and your rights. HTML at https://joinsimplesms.com/privacy - [Data Processing Addendum](https://joinsimplesms.com/dpa.md): How we process your recipients' data for you: GDPR, CCPA, SCCs, breach notice, and deletion. HTML at https://joinsimplesms.com/dpa - [Subprocessors](https://joinsimplesms.com/subprocessors.md): The kinds of third parties that help run SimpleSMS, and what data each one sees. HTML at https://joinsimplesms.com/subprocessors - [Data Retention](https://joinsimplesms.com/data-retention.md): How long we keep message content, opt-outs, logs, and account data, and what happens when you leave. HTML at https://joinsimplesms.com/data-retention ## Product - [Landing page](https://joinsimplesms.com) - [Pricing (HTML)](https://joinsimplesms.com/pricing) - [Pricing (Markdown)](https://joinsimplesms.com/pricing.md)