Blynk Cloud Device HTTPS API
Agent-ready OpenAPI document · curated by JenticIOTDevice ManagementapiKey6 EndpointsREST
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For Agents
Read and write Blynk datastream values, log device events, and check hardware connectivity for IoT devices on Blynk Cloud.
Use for: Read the current value of a Blynk datastream, Update a Blynk virtual pin to a new value, Set multiple Blynk datastreams in one call, Log a custom event against a Blynk device
Not supported: Does not provision new devices, manage user accounts, or build mobile dashboards - use for read/write access to datastream values, event logging, and connectivity checks on existing Blynk devices only.
Jentic publishes the only available OpenAPI specification for Blynk Cloud Device HTTPS API, keeping it validated and agent-ready. Blynk is an IoT platform with mobile and web dashboards, and the Device HTTPS API lets external systems read and write datastream values, log custom events, query historical data, and check whether a hardware device is currently online. Datastreams are the named virtual pins (V0, V1, etc.) that hardware writes to and dashboards read from. Authentication is per-device - each call carries a token query parameter scoped to a single Blynk device.
Install Jentic One Beta
Connect the Blynk Cloud Device HTTPS API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Blynk Cloud Device HTTPS API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fblynk.io%2Fblynk" | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fblynk.io%2Fblynk" | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Blynk Cloud Device HTTPS API.
Read the current value of a datastream by virtual pin name
Write a single datastream value to update device state
Update multiple datastreams at once with the batch endpoint
Log a custom named event against a device with optional description
Pull historical datastream data for charting and analytics
Check whether a device is currently connected to Blynk Cloud
Use Cases
Patterns agents use Blynk Cloud Device HTTPS API for, with concrete tasks.
★ Remote device control from a backend
Control a Blynk-connected device (relay, motor, light, plug) from a backend service or workflow engine without going through the Blynk mobile app. GET /update with the token, the datastream pin name, and the value triggers the device to act on the new value the next time it polls. GET /batch/update accepts multiple pin/value pairs in one call. Suitable for home automation hooks, scheduled actuator triggers, and remote support tools.
Call GET /update?token={token}&V0=1 to turn on a relay wired to virtual pin V0 on the target device.
Sensor data collection
Pull current and historical sensor values from devices reporting into Blynk for analytics or dashboards outside Blynk. GET /get returns the current value of a datastream, and GET /data returns the historical series with a configurable time window. Useful when an external time-series database, Grafana board, or analytics warehouse is the system of record.
Call GET /data?token={token}&dataStream=V1&period=1d to pull the last 24 hours of temperature readings from datastream V1.
Connectivity health check
Detect dropouts by checking whether a Blynk device is currently connected to the cloud. GET /isHardwareConnected returns a simple boolean for the device the token belongs to. Combine with /logEvent to record an event when a watchdog detects a sustained dropout, useful for fleet ops dashboards and alerting pipelines.
Call GET /isHardwareConnected?token={token} and, if false, call GET /logEvent?token={token}&code=offline_alert to record the dropout.
AI agent IoT command assistant
Let an AI agent take simple actions against Blynk-connected hardware on behalf of a user - turning a plug on or off, setting a thermostat target, or pulling a sensor reading. The agent searches Jentic for the right Blynk operation by intent, loads the schema, and executes with the device token held in your Jentic One instance. Suitable for voice-driven smart home assistants and chat-based IoT control prototypes.
Search Jentic for 'turn on a Blynk device', load the schema for GET /update, and execute it with token and V0=1 to turn the device on.
Key Endpoints
6 endpoints — jentic publishes the only available openapi specification for blynk cloud device https api, keeping it validated and agent-ready.
METHOD
PATH
DESCRIPTION
GET
/get
Read the current value of a datastream
GET
/update
Update a single datastream value
GET
/batch/update
Update multiple datastreams in one call
GET
/data
Pull historical datastream values
GET
/logEvent
Log a custom event against the device
GET
/isHardwareConnected
Check whether the device is online
GET
/get
Read the current value of a datastream
GET
/update
Update a single datastream value
GET
/batch/update
Update multiple datastreams in one call
GET
/data
Pull historical datastream values
GET
/logEvent
Log a custom event against the device
GET
/isHardwareConnected
Check whether the device is online
Why Jentic?
What agents get from Jentic-routed access to this vendor.
Setup
Wiring the Blynk Cloud API by hand means passing its device token as a query parameter, keeping it out of your own logs, and picking the right server address. Through Jentic you install once, import Blynk from the API Directory, store the token once, and your agent calls it.
Permission scoping
The Blynk device token itself binds every call to a single device, and the operation targets travel in query parameters rather than the URL path, so limit the agent to the operations it needs, such as reading a datastream or checking connectivity. You choose that set, so writing values with update or batch update is not included unless you add it.
Credential isolation
Your Blynk device token is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context.
Intent-based discovery
Agents search Jentic by intent such as 'read a Blynk datastream value' or 'check if a Blynk device is connected', and Jentic returns the matching operation with its input schema so the agent calls the right endpoint without browsing the docs.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Blynk Cloud Device HTTPS API through Jentic.
Why is there no official OpenAPI spec for Blynk Cloud Device HTTPS API?
Blynk publishes a developer documentation site but does not distribute a maintained OpenAPI 3 file. Jentic generates and maintains this spec so AI agents and developers can call the Blynk Device HTTPS API via standard tooling. It is validated against the live API and kept up to date. Get started with Jentic One, the self-hosted execution layer.
What authentication does the Blynk Device HTTPS API use?
Each call requires a device-scoped token passed as a query parameter (?token=...). The token is generated when a device is provisioned in Blynk and is unique per device. Through Jentic, the token is stored in the encrypted vault and injected at execution time, so the agent never handles the raw value, and per-device tokens stay isolated.
Can I write to multiple datastreams in one call?
Yes. GET /batch/update accepts multiple pin=value pairs in the query string (for example V0=1&V1=22.5&V2=on) so you can update several datastreams in a single request. This is more efficient than issuing repeated /update calls when several values change at once.
What are the rate limits for the Blynk Device HTTPS API?
Blynk applies per-device and per-account rate limits not enumerated in the spec. The published guidance is to keep request volume modest (a few requests per second per device); HTTP 429 responses come back when the limit is exceeded. Heavier ingestion should use Blynk's MQTT interface instead.
How do I read historical data through Jentic?
Search Jentic for 'pull Blynk datastream history', load the schema for GET /data, and execute it with the token, dataStream pin name, and a period (1h, 1d, 1w, 1m). Install with pip install jentic and call await client.execute(ExecutionRequest(...)). The response is a time-series array.
Can I check whether a device is online?
Yes. GET /isHardwareConnected with the device token returns a boolean indicating current connectivity to Blynk Cloud. This is suitable for liveness checks, watchdog scripts, and dashboard indicators.
Is the Blynk Cloud API free?
Blynk offers a free developer plan with limits on devices, datastream count, and history retention. Paid plans (Maker, Pro, Business) raise these limits and add features like white-label apps and on-prem deployment. The HTTPS API itself does not carry an additional fee.
Can I limit what my agent is allowed to do with the Blynk Cloud Device HTTPS API?
Yes. Because you run Jentic One yourself, your own rules decide which Blynk operations the agent may call, so you can grant read-only access such as GET /get and GET /isHardwareConnected while withholding write operations like GET /update and GET /batch/update. The device token binds every call to a single Blynk device, and the operation targets travel in query parameters rather than the URL path, so the agent can only reach the endpoints you have allowed on that one device. You decide that set, and writing datastream values stays excluded unless you add those operations.
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