diff --git a/hosting/nginx.dev.conf b/hosting/nginx.dev.conf
index a8cefe9ccc..747235e8ef 100644
--- a/hosting/nginx.dev.conf
+++ b/hosting/nginx.dev.conf
@@ -62,12 +62,6 @@ http {
       proxy_connect_timeout 120s;
       proxy_send_timeout 120s;
       proxy_http_version 1.1;
-
-      # Enable buffering for potentially large OIDC configs
-      proxy_buffering on;
-      proxy_buffer_size 16k;
-      proxy_buffers 4 32k;
-
       proxy_set_header Host $host;
       proxy_set_header Connection "";
 
diff --git a/lerna.json b/lerna.json
index 91980e0a15..bb71d10f41 100644
--- a/lerna.json
+++ b/lerna.json
@@ -1,6 +1,6 @@
 {
   "$schema": "node_modules/lerna/schemas/lerna-schema.json",
-  "version": "3.4.15",
+  "version": "3.4.16",
   "npmClient": "yarn",
   "concurrency": 20,
   "command": {
diff --git a/packages/builder/src/components/common/CodeEditor/CodeEditor.svelte b/packages/builder/src/components/common/CodeEditor/CodeEditor.svelte
index fbf74d1e9b..0f4bc64e2a 100644
--- a/packages/builder/src/components/common/CodeEditor/CodeEditor.svelte
+++ b/packages/builder/src/components/common/CodeEditor/CodeEditor.svelte
@@ -49,6 +49,7 @@
   import type { EditorMode } from "@budibase/types"
   import type { BindingCompletion, CodeValidator } from "@/types"
   import { validateHbsTemplate } from "./validator/hbs"
+  import { validateJsTemplate } from "./validator/js"
 
   export let label: string | undefined = undefined
   export let completions: BindingCompletion[] = []
@@ -356,6 +357,9 @@
     if (mode === EditorModes.Handlebars) {
       const diagnostics = validateHbsTemplate(value, validations)
       editor.dispatch(setDiagnostics(editor.state, diagnostics))
+    } else if (mode === EditorModes.JS) {
+      const diagnostics = validateJsTemplate(value, validations)
+      editor.dispatch(setDiagnostics(editor.state, diagnostics))
     }
   }
 
diff --git a/packages/builder/src/components/common/CodeEditor/validator/js.ts b/packages/builder/src/components/common/CodeEditor/validator/js.ts
new file mode 100644
index 0000000000..20fb5abd07
--- /dev/null
+++ b/packages/builder/src/components/common/CodeEditor/validator/js.ts
@@ -0,0 +1,101 @@
+import { Parser } from "acorn"
+import * as walk from "acorn-walk"
+
+import type { Diagnostic } from "@codemirror/lint"
+import { CodeValidator } from "@/types"
+
+export function validateJsTemplate(
+  code: string,
+  validations: CodeValidator
+): Diagnostic[] {
+  const diagnostics: Diagnostic[] = []
+
+  try {
+    const ast = Parser.parse(code, {
+      ecmaVersion: "latest",
+      locations: true,
+      allowReturnOutsideFunction: true,
+    })
+
+    const lineOffsets: number[] = []
+    let offset = 0
+    for (const line of code.split("\n")) {
+      lineOffsets.push(offset)
+      offset += line.length + 1 // +1 for newline character
+    }
+
+    let hasReturnStatement = false
+    walk.ancestor(ast, {
+      ReturnStatement(node, _state, ancestors) {
+        if (
+          // it returns a value
+          node.argument &&
+          // and it is top level
+          ancestors.length === 2 &&
+          ancestors[0].type === "Program" &&
+          ancestors[1].type === "ReturnStatement"
+        ) {
+          hasReturnStatement = true
+        }
+      },
+      CallExpression(node) {
+        const callee: any = node.callee
+        if (
+          node.type === "CallExpression" &&
+          callee.object?.name === "helpers" &&
+          node.loc
+        ) {
+          const functionName = callee.property.name
+          const from =
+            lineOffsets[node.loc.start.line - 1] + node.loc.start.column
+          const to = lineOffsets[node.loc.end.line - 1] + node.loc.end.column
+
+          if (!(functionName in validations)) {
+            diagnostics.push({
+              from,
+              to,
+              severity: "warning",
+              message: `"${functionName}" function does not exist.`,
+            })
+            return
+          }
+
+          const { arguments: expectedArguments } = validations[functionName]
+          if (
+            expectedArguments &&
+            node.arguments.length !== expectedArguments.length
+          ) {
+            diagnostics.push({
+              from,
+              to,
+              severity: "error",
+              message: `Function "${functionName}" expects ${
+                expectedArguments.length
+              } parameters (${expectedArguments.join(", ")}), but got ${
+                node.arguments.length
+              }.`,
+            })
+          }
+        }
+      },
+    })
+
+    if (!hasReturnStatement) {
+      diagnostics.push({
+        from: 0,
+        to: code.length,
+        severity: "error",
+        message: "Your code must return a value.",
+      })
+    }
+  } catch (e: any) {
+    diagnostics.push({
+      from: 0,
+      to: code.length,
+      severity: "error",
+      message: `Syntax error: ${e.message}`,
+    })
+  }
+
+  return diagnostics
+}
diff --git a/packages/builder/src/components/common/CodeEditor/validator/tests/js.spec.ts b/packages/builder/src/components/common/CodeEditor/validator/tests/js.spec.ts
new file mode 100644
index 0000000000..cd9fe4684c
--- /dev/null
+++ b/packages/builder/src/components/common/CodeEditor/validator/tests/js.spec.ts
@@ -0,0 +1,156 @@
+import { validateJsTemplate } from "../js"
+import { CodeValidator } from "@/types"
+
+describe("js validator", () => {
+  it("validates valid code", () => {
+    const text = "return 7"
+    const validators = {}
+
+    const result = validateJsTemplate(text, validators)
+    expect(result).toEqual([])
+  })
+
+  it("does not validate runtime errors", () => {
+    const text = "return a"
+    const validators = {}
+
+    const result = validateJsTemplate(text, validators)
+    expect(result).toEqual([])
+  })
+
+  it("validates multiline code", () => {
+    const text = "const foo='bar'\nreturn 123"
+    const validators = {}
+
+    const result = validateJsTemplate(text, validators)
+    expect(result).toEqual([])
+  })
+
+  it("allows return not being on the last line", () => {
+    const text = "const foo='bar'\nreturn 123\nconsole.log(foo)"
+    const validators = {}
+
+    const result = validateJsTemplate(text, validators)
+    expect(result).toEqual([])
+  })
+
+  it("throws on missing return", () => {
+    const text = "const foo='bar'\nbar='foo'"
+    const validators = {}
+
+    const result = validateJsTemplate(text, validators)
+    expect(result).toEqual([
+      {
+        from: 0,
+        message: "Your code must return a value.",
+        severity: "error",
+        to: 25,
+      },
+    ])
+  })
+
+  it("checks that returns are at top level", () => {
+    const text = `
+    function call(){
+      return 1
+    }`
+    const validators = {}
+
+    const result = validateJsTemplate(text, validators)
+    expect(result).toEqual([
+      {
+        from: 0,
+        message: "Your code must return a value.",
+        severity: "error",
+        to: text.length,
+      },
+    ])
+  })
+
+  describe("helpers", () => {
+    const validators: CodeValidator = {
+      helperFunction: {
+        arguments: ["a", "b", "c"],
+      },
+    }
+
+    it("validates helpers with valid params", () => {
+      const text = "return helpers.helperFunction(1, 99, 'a')"
+
+      const result = validateJsTemplate(text, validators)
+      expect(result).toEqual([])
+    })
+
+    it("throws on too few params", () => {
+      const text = "return helpers.helperFunction(100)"
+
+      const result = validateJsTemplate(text, validators)
+      expect(result).toEqual([
+        {
+          from: 7,
+          message: `Function "helperFunction" expects 3 parameters (a, b, c), but got 1.`,
+          severity: "error",
+          to: 34,
+        },
+      ])
+    })
+
+    it("throws on too many params", () => {
+      const text = "return helpers.helperFunction( 1, 99, 'a', 100)"
+
+      const result = validateJsTemplate(text, validators)
+      expect(result).toEqual([
+        {
+          from: 7,
+          message: `Function "helperFunction" expects 3 parameters (a, b, c), but got 4.`,
+          severity: "error",
+          to: 47,
+        },
+      ])
+    })
+
+    it("validates helpers on inner functions", () => {
+      const text = `function call(){
+                      return helpers.helperFunction(1, 99)
+                    }
+                    return call()`
+
+      const result = validateJsTemplate(text, validators)
+      expect(result).toEqual([
+        {
+          from: 46,
+          message: `Function "helperFunction" expects 3 parameters (a, b, c), but got 2.`,
+          severity: "error",
+          to: 75,
+        },
+      ])
+    })
+
+    it("validates multiple helpers", () => {
+      const text =
+        "return helpers.helperFunction(1, 99, 'a') + helpers.helperFunction(1) + helpers.another(1) + helpers.another()"
+      const validators: CodeValidator = {
+        helperFunction: {
+          arguments: ["a", "b", "c"],
+        },
+        another: { arguments: [] },
+      }
+
+      const result = validateJsTemplate(text, validators)
+      expect(result).toEqual([
+        {
+          from: 44,
+          message: `Function "helperFunction" expects 3 parameters (a, b, c), but got 1.`,
+          severity: "error",
+          to: 69,
+        },
+        {
+          from: 72,
+          message: `Function "another" expects 0 parameters (), but got 1.`,
+          severity: "error",
+          to: 90,
+        },
+      ])
+    })
+  })
+})
diff --git a/packages/builder/src/components/common/bindings/BindingPanel.svelte b/packages/builder/src/components/common/bindings/BindingPanel.svelte
index 2c35acdf2d..9ebbc91309 100644
--- a/packages/builder/src/components/common/bindings/BindingPanel.svelte
+++ b/packages/builder/src/components/common/bindings/BindingPanel.svelte
@@ -377,6 +377,7 @@
               value={jsValue ? decodeJSBinding(jsValue) : jsValue}
               on:change={onChangeJSValue}
               {completions}
+              {validations}
               mode={EditorModes.JS}
               bind:getCaretPosition
               bind:insertAtPos
diff --git a/packages/worker/package.json b/packages/worker/package.json
index 28728272ca..53d14dacee 100644
--- a/packages/worker/package.json
+++ b/packages/worker/package.json
@@ -62,7 +62,6 @@
     "koa-body": "4.2.0",
     "koa-compress": "4.0.1",
     "koa-passport": "4.1.4",
-    "koa-redis": "^4.0.1",
     "koa-send": "5.0.1",
     "koa-session": "5.13.1",
     "koa-static": "5.0.0",
diff --git a/packages/worker/src/api/routes/global/tests/auth.spec.ts b/packages/worker/src/api/routes/global/tests/auth.spec.ts
index f89cb4a027..bff959469e 100644
--- a/packages/worker/src/api/routes/global/tests/auth.spec.ts
+++ b/packages/worker/src/api/routes/global/tests/auth.spec.ts
@@ -311,7 +311,7 @@ describe("/api/global/auth", () => {
       })
     })
 
-    describe.skip("GET /api/global/auth/:tenantId/oidc/callback", () => {
+    describe("GET /api/global/auth/:tenantId/oidc/callback", () => {
       it("logs in", async () => {
         const email = `${generator.guid()}@example.com`
 
diff --git a/packages/worker/src/index.ts b/packages/worker/src/index.ts
index f382aa8a20..0547afab38 100644
--- a/packages/worker/src/index.ts
+++ b/packages/worker/src/index.ts
@@ -4,7 +4,7 @@ if (process.env.DD_APM_ENABLED) {
 
 // need to load environment first
 import env from "./environment"
-import Application, { Middleware } from "koa"
+import Application from "koa"
 import { bootstrap } from "global-agent"
 import * as db from "./db"
 import { sdk as proSdk } from "@budibase/pro"
@@ -20,7 +20,6 @@ import {
   cache,
   features,
 } from "@budibase/backend-core"
-import RedisStore from "koa-redis"
 
 db.init()
 import koaBody from "koa-body"
@@ -53,28 +52,7 @@ app.proxy = true
 app.use(handleScimBody)
 app.use(koaBody({ multipart: true }))
 
-const sessionMiddleware: Middleware = async (ctx: any, next: any) => {
-  const redisClient = await new redis.Client(
-    redis.utils.Databases.SESSIONS
-  ).init()
-  return koaSession(
-    {
-      // @ts-ignore
-      store: new RedisStore({ client: redisClient.getClient() }),
-      key: "koa:sess",
-      maxAge: 86400000, // one day
-      httpOnly: true,
-      secure: process.env.NODE_ENV === "production",
-      sameSite: "strict",
-      rolling: true,
-      renew: true,
-    },
-    app
-  )(ctx, next)
-}
-
-app.use(sessionMiddleware)
-
+app.use(koaSession(app))
 app.use(middleware.correlation)
 app.use(middleware.pino)
 app.use(middleware.ip)
diff --git a/packages/worker/src/koa-redis.d.ts b/packages/worker/src/koa-redis.d.ts
deleted file mode 100644
index ad1b7a46f1..0000000000
--- a/packages/worker/src/koa-redis.d.ts
+++ /dev/null
@@ -1 +0,0 @@
-declare module "koa-redis" {}
diff --git a/yarn.lock b/yarn.lock
index 8f611e224c..ceae41458c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2695,13 +2695,6 @@
   dependencies:
     regenerator-runtime "^0.14.0"
 
-"@babel/runtime@^7.8.3":
-  version "7.26.9"
-  resolved "https://registry.yarnpkg.com/@babel/runtime/-/runtime-7.26.9.tgz#aa4c6facc65b9cb3f87d75125ffd47781b475433"
-  integrity sha512-aA63XwOkcl4xxQa3HjPMqOP6LiK0ZDv3mUPYEFXkpHbaFjtGggE1A61FjFzJnB+p7/oy2gA8E+rcBNl/zC1tMg==
-  dependencies:
-    regenerator-runtime "^0.14.0"
-
 "@babel/template@^7.22.15", "@babel/template@^7.22.5", "@babel/template@^7.25.9", "@babel/template@^7.3.3":
   version "7.25.9"
   resolved "https://registry.yarnpkg.com/@babel/template/-/template-7.25.9.tgz#ecb62d81a8a6f5dc5fe8abfc3901fc52ddf15016"
@@ -9048,14 +9041,7 @@ co-body@^5.1.1:
     raw-body "^2.2.0"
     type-is "^1.6.14"
 
-co-wrap-all@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/co-wrap-all/-/co-wrap-all-1.0.0.tgz#370ae3e8333510a53f6b2f7fdfbe4568a11b7ecf"
-  integrity sha512-aru6gLi2vTUazr+MxVm3Rv6ST7/EKtFj9BrfkcOrbCO2Qv6LqJdE71m88HhHiBEviKw/ucVrwoGLrq2xHpOsJA==
-  dependencies:
-    co "^4.0.0"
-
-co@^4.0.0, co@^4.6.0:
+co@^4.6.0:
   version "4.6.0"
   resolved "https://registry.yarnpkg.com/co/-/co-4.6.0.tgz#6ea6bdf3d853ae54ccb8e47bfa0bf3f9031fb184"
   integrity sha512-QVb0dM5HvG+uaxitm8wONl7jltx8dqhfU33DcqtOZcLSVIKSDDLDi7+0LbAKiyI8hD9u42m2YxXSkMGWThaecQ==
@@ -13191,7 +13177,7 @@ ioredis@5.3.2:
     redis-parser "^3.0.0"
     standard-as-callback "^2.1.0"
 
-ioredis@^4.14.1, ioredis@^4.28.5:
+ioredis@^4.28.5:
   version "4.28.5"
   resolved "https://registry.yarnpkg.com/ioredis/-/ioredis-4.28.5.tgz#5c149e6a8d76a7f8fa8a504ffc85b7d5b6797f9f"
   integrity sha512-3GYo0GJtLqgNXj4YhrisLaNNvWSNwSS2wS4OELGfGxH8I69+XfNdnmV1AyN+ZqMh0i7eX+SWjrwFKDBDgfBC1A==
@@ -14691,16 +14677,6 @@ koa-pino-logger@4.0.0:
   dependencies:
     pino-http "^6.5.0"
 
-koa-redis@^4.0.1:
-  version "4.0.1"
-  resolved "https://registry.yarnpkg.com/koa-redis/-/koa-redis-4.0.1.tgz#57ac1b46d9ab851221a9f4952c1e8d4bf289db40"
-  integrity sha512-o2eTVNo1NBnloeUGhHed5Q2ZvJSLpUEj/+E1/7oH5EmH8WuQ+QLdl/VawkshxdFQ47W1p6V09lM3hCTu7D0YnQ==
-  dependencies:
-    "@babel/runtime" "^7.8.3"
-    co-wrap-all "^1.0.0"
-    debug "^4.1.1"
-    ioredis "^4.14.1"
-
 koa-router@^10.0.0:
   version "10.1.1"
   resolved "https://registry.yarnpkg.com/koa-router/-/koa-router-10.1.1.tgz#20809f82648518b84726cd445037813cd99f17ff"