overrideConfig.vars and stateMemory ignored by /api/v1/prediction (vars not populated)

[Sofia-Happy-Wibes]

Describe the bug

Hi Flowise team — I’m hitting a blocking issue where API runtime overrides (overrideConfig.vars and overrideConfig.stateMemory) are not being applied to flows when calling the prediction API. I’m using AgentFlow V2 (Flowise V3) and tested both on a Railway deployment and on Flowise cloud. Per the Context7 docs, overrideConfig.vars should make variables available as $vars. at runtime and stateMemory should be able to replace flow state keys, but neither is being applied in my tests (while overrideConfig.sessionId is being applied). Please see reproduction steps, payloads, observed vs expected behavior, logs/IDs, and suggested checks below.

Severity:
High: prevents server-side integrations (Make, backend callers) from passing contextual variables into flows, which disables linking conversations to users and other critical runtime behavior.

Thank you in advance!
I’d appreciate confirmation that this is expected configuration behavior (and the exact config to enable), or a plan/fix if it’s a bug. If helpful, I can also provide the flow export and my test curl commands and responses.

Kind regards,
Sophie

To Reproduce

Summary / impact

overrideConfig.sessionId is applied (available as sessionId in the returned run), but overrideConfig.vars and overrideConfig.stateMemory are ignored — flow.state keys remain empty and mustache templates like {{$vars.user_name}} are returned verbatim in replies.
This blocks integrations (Make) that need to pass runtime variables (user info, session data) into AgentFlow runs.
Environment

Flowise deployed on Railway (
https://flowise-production-889b.up.railway.app/
)
Also tested on app.flowise.ai (Flowise cloud) — observed same behavior in my tests
AgentFlow V2 / Flowise V3
Minimal reproduction (exact payloads used)

overrideConfig.vars test (should make vars.session_id available)
POST https:///api/v1/prediction/<FLOW_ID>
Content-Type: application/json
Body:
{
"question": "start",
"overrideConfig": {
"sessionId": "b86ef7a4-5376-42f2-83a0-d479db4215e6",
"vars": {
"user_name": "Sophie",
"session_id": "b86ef7a4-5376-42f2-83a0-d479db4215e6"
}
}
}

stateMemory test (alternative API for setting state directly)
POST https:///api/v1/prediction/<FLOW_ID>
Content-Type: application/json
Body:
{
"question": "start",
"overrideConfig": {
"stateMemory": [
{ "Key": "session_id", "Operation": "Replace", "Default Value": "test-state-456" },
{ "Key": "user_name", "Operation": "Replace", "Default Value": "Alice State" }
]
}
}

Observed results (examples from returned response)

HTTP 200 returned and the flow executed.
Returned agentFlowExecutedData shows start node and direct-reply nodes, but every node’s state shows: "session_id": "", "user_name": ""
Direct Reply output contains literal templates: "Bonjour {{
vars.user_name}}, ({{
vars.session_id}})"
In Railway response header for one call: x-railway-request-id: He7-WzHLRJihJw4Y0-QtfA (timestamp: 2025-09-03T17:03:05Z). (I can provide further request IDs/timestamps on request.)
On Flowise cloud I tested the same "vars" payload and got the same result (returned sessionId applied, but $vars not populated).

Expected behavior

Expected behavior (per Context7 docs)

overrideConfig.vars should populate
vars. at runtime and allow mustache templates {{
vars.}} to render.
overrideConfig.stateMemory (if supported) should replace $flow.state keys as specified.
overrideConfig.sessionId should be available as $flow.sessionId.
What I’ve already verified

JSON body and Content-Type are correct; payload is being received by the server (HTTP 200).
I corrected earlier typo (I initially sent "variables" instead of "vars" but then tested with correct "vars" and still saw the same issue).
Start node is chat input (input.question present in returned JSON), so chat-input-style overrideConfig.vars is the right mechanism per docs.
Using curl (file-based -d @payload.json) and Make both replicate the behavior.
Custom functions are not an option in my environment, and I want this fixed without needing custom JS.
Possible causes to check (based on Context7 docs + typical deployment settings)

A server/deployment-level toggle is disabling API overrides (overrideConfig.vars/stateMemory) for security. Flowise deployments may require a top-level flag/env var to allow overrides.
The app might accept overrideConfig.sessionId but ignore vars/stateMemory unless a specific env var is enabled.
A mismatch between documented field names and implementation (e.g., vars vs variables) — I tested the documented "vars" name.
stateMemory support may vary by build/version — clarify whether stateMemory is supported in this version and whether the API shape is exactly as above.
Requested action / questions

Please confirm whether the prediction endpoint on both Railway and Flowise cloud should accept overrideConfig.vars and overrideConfig.stateMemory and populate flow.state accordingly (per Context7 docs). If yes:

Please check why overrides are being ignored for my requests (the server receives the request but filters out vars/stateMemory).
If a server-level toggle is required to enable overrides, please confirm:
The exact environment variable name(s) or configuration key(s) to enable overrides (examples I tried or that documentation mentions: ALLOW_OVERRIDE, ALLOW_OVERRIDE_CONFIG, FLOWISE_ALLOW_OVERRIDE, OVERRIDE_CONFIG_ENABLED). Please give the authoritative env var name(s) and acceptable values.
If stateMemory is supported, confirm the correct payload shape and whether any extra permission or config is required to allow it.
If this is an unintended bug (overrides accepted only partially), please triage and advise timeline for a fix — this significantly impacts integrations that pass runtime context via Make / server-to-server calls.

If you need more artifacts, I can provide:

Full response JSON for these requests (I have the response bodies),
Request IDs & timestamps (e.g., Railway request id He7-WzHLRJihJw4Y0-QtfA at 2025-09-03T17:03:05Z),
The flow JSON (Start node and Direct Reply nodes),
The exact curl commands used to reproduce.

Screenshots

No response

Flow

No response

Use Method

Flowise Cloud

Flowise Version

3

Operating System

macOS

Browser

Chrome

Additional context

I am trying to create an agent which starts the conversation based on information injected into the State via MAKE.com