Data & Storage · Integration
Message Validator
Add Message Validator to your product for your customers, and give your AI agents governed access to it.
Embed a Message Validator integration so payload validation runs on each customer's own connection from inside your product, rather than through a shared key you have to meter. Validation usually sits in the middle of a pipeline, so the value of having it behind the same gateway as the systems that produce and consume those messages is that a rejected payload can be traced end to end. Rules and field mapping are per-tenant configuration, so a customer whose messages look different is a mapping change rather than a release. fastn holds the credentials, handles retries and rate limits, and logs every call, and the same governed connection is what your AI agents use.
In your product
Embedded for your customers. Per-tenant auth, no per-customer code, maintained by fastn.
Let each customer connect their own account so validation runs under their credentials rather than a shared key.
Validate a payload before your product forwards it, so a malformed message is caught at the edge instead of failing downstream.
Record the validation result per tenant so a rejected message can be traced back to exactly what was sent.
Put validation in front of the systems that produce and consume those messages without writing a client for it yourself.
For your AI agents
Governed, audited access for the agents you build, through the MCP server.
An agent validates a payload before it writes into another connected system, with each call audited.
An agent explains why a message was rejected and what would make it acceptable.
An agent checks a batch of messages and reports which would fail, leaving the fix to a human.
Example prompt
Validate this payload and tell me exactly which part of it is not acceptable.
Set up Message Validator in 4 steps
- 01Enable the Message Validator connector in your fastn dashboard.
- 02Have each customer supply their own credentials so validation runs under their account.
- 03Map the payloads and rules you validate, per customer, as configuration.
- 04Call it from your product and expose the same connection to your agents through the MCP gateway.
Why teams use the Message Validator integration
What you get by embedding it with fastn instead of building it yourself.
- Ship payload validation without building it. It checks a message against rules you configure inside a governed workflow, so a malformed payload is caught before it reaches your product.
- Handle the part that actually costs time: deciding what a failure should do. Rejecting, routing to a dead-letter path and passing through with a warning are different products, and the choice belongs per tenant.
- One step serves your product and your agents. The same validation runs whether a workflow or an agent produced the payload, and every result is logged.
Used by these teams
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Hugging FaceMessage Validator integration FAQ
How do I add a Message Validator step to my product?
Enable the Message Validator step in your fastn dashboard and place it in a workflow. There is nothing for a customer to authenticate, because it operates on the payload you hand it rather than on a third-party account. Setup is 4 steps.
Is there a Message Validator account to connect?
No. Message Validator is a step inside a workflow rather than a third-party service, so there is nothing for a customer to authorise. It runs on the payload you hand it, and each run is logged per tenant like any other action.
Can AI agents use this Message Validator integration?
Yes. The same connection is exposed to your agents through the fastn MCP gateway, with permissions scoped per tenant and every call audited. An agent validates a payload before it writes into another connected system, with each call audited.
Who maintains the Message Validator integration?
fastn does. When Message Validator changes an endpoint, deprecates a field or alters its auth, the fix lands in the connector rather than in your backlog, and your customers' connections keep working.
What happens to a payload that fails validation?
Whatever you configure per tenant: reject it, route it aside for review, or let it through with the failure recorded. The validation result is logged either way, so a rejected message can be explained rather than merely dropped.
What can I build with the Message Validator integration?
A common starting point: let each customer connect their own account so validation runs under their credentials rather than a shared key. Teams also use it for the other use cases listed above, and expose it to agents for governed reads and writes.
How much does the Message Validator integration cost?
It is included. Pricing is based on connected accounts, not on how many connectors you enable, so adding Message Validator does not change your per-connector cost. You can start free with 3 connected accounts.
Add Message Validator to your product
Start free with 3 connected accounts. No sales call required, and no per-customer integration code.