# Send SMS with Rails

Source: https://jointextkit.com/docs/send-with-rails
Index: https://jointextkit.com/llms.txt

Send a text from Rails with a small service object over TextKit's REST API. No gem to install.

## Prompt for your AI agent

Paste this into Claude Code, Cursor or any coding agent to have it do the
integration:

```text
Add SMS sending to this Rails project with TextKit.

- Docs for this stack: https://jointextkit.com/docs/send-with-rails.md
- API: POST https://api.jointextkit.com/v1/messages with `Authorization: Bearer
  <key>` and a JSON body `{"to": "+1...", "body": "..."}`.
- There is no Ruby gem: POST JSON to https://api.jointextkit.com/v1/messages
  with Net::HTTP from a service object, and call it from an Active Job.
- Read the key from the `TEXTKIT_API_KEY` environment variable. Never hardcode
  it or send it to the browser.
- Phone numbers are E.164 and US or Canada only (`+1` followed by 10 digits).
- A test key (`ssms_sk_test_`) simulates: `+15005550006` always ends `delivered`
  and no phone gets a text.
- Errors are JSON: `{"error": {"code", "message", "param"}}` with a 4xx status.
  On `429`, wait `Retry-After` seconds and retry.
- Send only from server code that runs after a real event (a signup, an order).
  Never expose an endpoint that texts any number a visitor types.
```

## Before you start

- **An API key.** [Create a free account](/signup) and copy the test key
  (`ssms_sk_test_...`) from Home in the console. It works at once, no card.
- **Rails 6 or later.**
- Put the key in an environment variable:

```bash
export TEXTKIT_API_KEY=ssms_sk_test_...
```

## 1. Add a service object

Create `app/services/textkit.rb`:

```ruby
require "net/http"

class Textkit
  ENDPOINT = URI("https://api.jointextkit.com/v1/messages")

  class Error < StandardError; end

  def self.send_sms(to:, body:)
    req = Net::HTTP::Post.new(ENDPOINT)
    req["Authorization"] = "Bearer #{ENV.fetch("TEXTKIT_API_KEY")}"
    req["Content-Type"] = "application/json"
    req.body = { to: to, body: body }.to_json

    res = Net::HTTP.start(ENDPOINT.hostname, ENDPOINT.port, use_ssl: true) { |http| http.request(req) }
    data = JSON.parse(res.body)
    raise Error, "#{data.dig("error", "code")}: #{data.dig("error", "message")}" unless res.is_a?(Net::HTTPSuccess)

    data
  end
end
```

## 2. Send a test

```bash
bin/rails runner 'puts Textkit.send_sms(to: "+15005550006", body: "Hello from TextKit")["id"]'
```

It prints the message ID (`msg_...`).

## 3. Send from a job

```ruby
class SendSmsJob < ApplicationJob
  queue_as :default

  def perform(to, body)
    Textkit.send_sms(to: to, body: body)
  end
end
```

```ruby
SendSmsJob.perform_later(user.phone, "Your order shipped.")
```

## What the test key did

`+15005550006` is a sandbox number: the send comes back `delivered` and no
phone gets a text (the response says `"simulated": true`). Put your own
verified phone in `to` and the test key texts it for real. See
[Sandbox & test numbers](/docs/sandbox).

## Handle errors

`Textkit.send_sms` raises `Textkit::Error` with the API's code. A failed request returns a 4xx status and a JSON body
`{"error": {"code": "...", "message": "...", "param": "..."}}`. On `429
rate_limited`, wait the `Retry-After` seconds and try again. Send an
`Idempotency-Key` header (any unique string per message) and a retried request
returns the first result instead of sending twice.

| Status | Code | What to do |
| --- | --- | --- |
| 400 | `invalid_request` | A field is missing or malformed; `param` names it. |
| 401 | `invalid_api_key` | The key is missing, revoked or mistyped. |
| 402 | `insufficient_credits` | Add credits; nothing was sent or charged. |
| 403 | `recipient_opted_out` | They texted STOP. Do not retry. |
| 429 | `rate_limited` | Wait `Retry-After` seconds, then retry. |

Every code is in [Errors](/docs/errors).

## Go live

1. **Add a number** in the [console](/console).
2. **Register your use case.** We file your 10DLC registration; toll-free
   numbers use a guided verification form. Until carriers approve it, the number
   texts only your verified numbers. See [Compliance & registration](/docs/compliance).
3. **Swap in a live key** (`ssms_sk_live_...`). The code stays the same.

## Next steps

- [Webhooks](/docs/webhooks): delivery receipts and replies, pushed to your server.
- [Verify](/docs/verify): one-time codes in two calls, billed only when verified.
- [Send an SMS](/docs/api/messages/send): every field the endpoint takes.
- [All quickstarts](/docs/quickstarts): the same guide for other languages and frameworks.