Textbelt
MessagingConnect AI agents to Textbelt, a deliberately simple SMS API for developers. Agents send SMS, run one time password verification flows, and check delivery status and remaining quota so lightweight text notifications work without any account setup.
What This Integration Enables
Textbelt is deliberately small, and the small surface is the product rather than a gap in it. Six actions: send an SMS, send an SMS carrying a rendered chart, issue a one time password, verify it, look up a delivery status, read the remaining quota. There is no account to configure, no sender registry, no subscription tier and no dashboard. You buy credit against a key and you spend it. For a founder or a small operations team that needs a phone to ring when something breaks, that is a materially different proposition from a gateway that wants a business verification before it will carry the first message. It is the reason to reach for this connector rather than a larger one.
The small surface comes with one behavior that has to be designed around, and it is the reason a naive integration of this API silently loses messages. Textbelt never answers 401 or 403. An invalid key, an exhausted quota and a missing parameter all arrive as HTTP 200 with a body saying the call failed. An ordinary request helper resolves that as a success, the message never leaves, no credit moves, and the flow carries on as though a customer had been texted. This connector reads the success flag out of every body and raises the failure as an error, normalizing the flag first because a vendor field is not guaranteed to be a real JSON boolean and the string false is truthy in JavaScript. Failed sends become automation exceptions instead of clean log lines.
Two more things are worth knowing before building. The vendor ships a documented dry run: appending a test suffix to the key makes the send route answer as though the message would go out, without deducting credit and without delivering anything, and it is exposed here as a Test Mode toggle on Send SMS. It is documented for that one route, so it appears on that one action, because offering it elsewhere would send a real message while telling the operator it was a rehearsal. And Send Verification Code returns the generated code in cleartext in its own response, which means a one time password lands in flow data. Anything that logs, stores or forwards that step's output is handling a live credential, and the access decision should be read from Verify Code rather than from the code itself.
Without FlowRunner
With FlowRunner
Use Case Scenarios
On call alerting without an on call platform
A small team wants a text when a queue backs up or a nightly job fails. The agent watches the condition, composes a message that fits a lock screen, and calls Send SMS. Because the connector raises Textbelt's 200 shaped failures as real errors, an exhausted quota wakes somebody about the quota rather than being counted as an alert delivered. Supplying a reply webhook URL on the send makes Textbelt POST any reply to that URL, which is how a one word acknowledgement can close the alert without anyone opening a tool. Get Quota runs on a schedule and posts to Slack when the balance gets thin, with the honest caveat that a zero reading means no credit available and is not by itself proof the key is wrong.
Verification for a product that does not have a login yet
An early product needs phone verification and does not want to stand up an OTP service for it. Send Verification Code generates a six digit code against a user id you choose, delivers it by SMS, and holds it for the validity window. Verify Code checks the user's input and answers with a validity flag, and that flag is what the flow branches on. A wrong code, an expired code and an unknown user id all come back as a processed request with a false result, which is a normal answer rather than a failure. The verified state is written to Airtable or the product database, and the code itself is never carried forward, because the send response contains it in cleartext and treating that output as ordinary data is how a credential ends up in a log.
A metric pushed as a picture
A weekly revenue or error rate figure is more useful as a shape than a number. Send SMS With Chart takes either a set of data points that Textbelt renders as a line or bar graph, or a full chart definition rendered through a chart service for complete control. The agent pulls the series from Snowflake, builds the definition, and sends it to the two or three phones that care. It is worth knowing what this route costs and what it does not offer. It is billed whether or not the chart renders as intended, chart delivery is oriented toward US numbers, and the vendor publishes no response shape for it, so the sample result here is an inference from the ordinary send envelope rather than something transcribed.
Human-in-Loop Highlight
The gate on Textbelt sits on Send SMS With Chart, and the reason is precise: it is the one send this vendor's own dry run does not cover. Textbelt documents the test suffix for the plain send route only, so Test Mode appears on Send SMS and nowhere else. That is the correct decision, because a Test Mode toggle on a route that ignores it would deliver a real, billed message while reporting a rehearsal. But it leaves the charted send as the only outbound action here with no rehearsal available at all. The action refuses the call before spending anything when neither chart mode is supplied or when both are, and it refuses a chart type outside the two documented ones, so the obvious malformed cases fail free. What it cannot refuse is a definition that is valid, renders, bills, and is simply wrong: a series with the axes inverted, a date range off by a week, a label that reveals a customer name to a group message.
So the flow renders first and sends second. The same chart definition is drawn through QuickChart, which is the renderer the full definition path uses anyway, and the resulting image goes to a person before a message goes to a handset. Into Slack: "Weekly error rate chart ready for the three on call numbers. Rendered preview attached. Send SMS With Chart is billed per message, has no test mode, and delivery of chart messages is oriented toward US numbers, so all three recipients are US. Send, or adjust the series first?" A person looks at a picture and answers in two seconds, which is the cheapest possible review and the only one available here.
That is the digital andon cord put exactly where the platform stops being able to help, and it is worth saying what makes it the right gate rather than a cautious one. On the plain send there is no gate at all, because the vendor already shipped the rehearsal and an agent can run it unattended. Asking a human to approve a message the platform will simulate for free is theater. The judgment is only genuinely human on the one route where the simulation does not exist, and confining the gate to that route is what keeps Orchestration as a Service from turning into an approval queue. Alongside it, one standing rule rather than a gate: the response from Send Verification Code contains the live code, so that step's output is treated as a secret and never forwarded into a channel a person reads.
Agent Capabilities
6 actionsMessaging
2- Send SMS Sends a single message through Textbelt's paid carrier routes, with the recipient given as a plain ten digit number for the US and Canada or in international format elsewhere. Supplying a reply webhook URL makes Textbelt POST any reply to it, which works for US numbers only and not on the shared free key. Turning on Test Mode exercises the path without deducting credit and without delivering anything, which is the vendor's own documented way to rehearse a send.
- Send SMS With Chart Sends an SMS or MMS carrying a rendered chart image, which is how a metric, a trend or an alert graph reaches a phone as a shape rather than a number. Supply either data points for a simple bar or line graph or a full chart definition for complete control, and exactly one of the two is required. This action is billed and reaches a real handset, and the vendor documents no test mode for it.
Verification
2- Send Verification Code Generates a one time password and sends it by SMS against a user id you supply, defaulting to six digits and a short validity window. A custom message must carry the code placeholder. This sends a real billed message, and the generated code is returned in the response in cleartext, so the step's output should be treated as a secret rather than as ordinary flow data.
- Verify Code Checks a code the user entered against the one sent to that user id. Read the validity flag rather than the request outcome to decide whether to let somebody through: a wrong code, an expired code and an unknown user id all arrive as a successfully processed request with a false result. This action sends nothing and consumes no credit.
Reporting
1- Get Delivery Status Looks up what happened to a message using the text id returned by a send. Statuses are retained for about a week and are not standardized between carriers, so some confirm handset receipt, some report delivered on transmission, and some can only ever report sent. An unrecognized id answers unknown rather than erroring, so this cannot be used to validate an id.
Account
1- Get Quota Reads how much credit is left on the configured key, which makes it the natural gate before a batch and the natural source of a low balance alert. It cannot tell an invalid key from an empty one, because an unrecognized key also answers with a quota of zero, so a zero reading means no credit available rather than proof the key is wrong.
Frequently Asked Questions
What can FlowRunner do with Textbelt?
FlowRunner agents can run Send SMS, Send SMS With Chart, and Send Verification Code in Textbelt, plus 3 more actions.
Does connecting Textbelt to FlowRunner require OAuth?
No. Textbelt connects to FlowRunner with an API key, no OAuth flow required.
Can Textbelt trigger a FlowRunner workflow automatically?
Textbelt doesn't currently expose triggers in FlowRunner. It connects as an action step inside workflows started by another trigger.
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