# Send SMS with Rust

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

Send your first text from Rust with reqwest and TextKit's REST API.

## 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 Rust project with TextKit.

- Docs for this stack: https://jointextkit.com/docs/send-with-rust.md
- API: POST https://api.jointextkit.com/v1/messages with `Authorization: Bearer
  <key>` and a JSON body `{"to": "+1...", "body": "..."}`.
- There is no Rust crate: POST JSON to https://api.jointextkit.com/v1/messages
  with reqwest.
- 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.
- **Rust 1.70 or later.**
- Put the key in an environment variable:

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

## 1. Add the crates

```bash
cargo new send-sms && cd send-sms
cargo add reqwest --features json
cargo add tokio --features full
cargo add serde_json
```

## 2. Send an SMS

Replace `src/main.rs`:

```rust
use serde_json::{json, Value};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let key = std::env::var("TEXTKIT_API_KEY")?;

    let res = reqwest::Client::new()
        .post("https://api.jointextkit.com/v1/messages")
        .bearer_auth(key)
        .json(&json!({ "to": "+15005550006", "body": "Hello from TextKit" }))
        .send()
        .await?;

    let status = res.status();
    let body: Value = res.json().await?;
    let text = |v: &Value| v.as_str().unwrap_or_default().to_string();
    if !status.is_success() {
        eprintln!("{}: {}", text(&body["error"]["code"]), text(&body["error"]["message"]));
        std::process::exit(1);
    }

    println!("{} {}", text(&body["id"]), text(&body["status"]));
    Ok(())
}
```

## 3. Run it

```bash
cargo run
```

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

## 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

The program above already stops on an error and prints its 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.