What causes "parameter 'memorySizeInMb' must not be NaN, but is" in remotion-dev/remotion?

Check the upstream source of memorySizeInMb and ensure it is a finite integer before passing it; default to DEFAULT_MEMORY_SIZE (2048) when the value is missing or NaN.

remotion-dev/remotion · error · TypeError

parameter 'memorySizeInMb' must not be NaN, but is

Error message

parameter 'memorySizeInMb' must not be NaN, but is

What it means

Thrown by validateMemorySize() in @remotion/lambda-client when the memorySizeInMb option is the numeric value NaN. Remotion Lambda must allocate a concrete amount of memory to the render function (between 512 and 10240 MB), and NaN is not an allocatable size. The check runs after the typeof guard, so only a real number that is NaN reaches it.

Source

Thrown at packages/lambda-client/src/validate-memory-size.ts:11

import {MAX_MEMORY, MIN_MEMORY} from './constants';

export const validateMemorySize = (memorySizeInMb: unknown) => {
	if (typeof memorySizeInMb !== 'number') {
		throw new TypeError(
			`parameter 'memorySizeInMb' must be a number, got a ${typeof memorySizeInMb}`,
		);
	}

	if (Number.isNaN(memorySizeInMb)) {
		throw new TypeError(`parameter 'memorySizeInMb' must not be NaN, but is`);
	}

	if (!Number.isFinite(memorySizeInMb)) {
		throw new TypeError(
			`parameter 'memorySizeInMb' must be finite, but is ${memorySizeInMb}`,
		);
	}

	if (memorySizeInMb < MIN_MEMORY || memorySizeInMb > MAX_MEMORY) {
		throw new TypeError(
			`parameter 'memorySizeInMb' must be between ${MIN_MEMORY} and ${MAX_MEMORY}, but got ${memorySizeInMb}`,
		);
	}

	if (memorySizeInMb % 1 !== 0) {
		throw new TypeError(
			`parameter 'memorySizeInMb' must be an integer but got ${memorySizeInMb}`,
		);

View on GitHub (pinned to 78fe4bb3fd)

Solutions

Check the upstream source of memorySizeInMb and ensure it is a finite integer before passing it; default to DEFAULT_MEMORY_SIZE (2048) when the value is missing or NaN.
Wrap the read with Number.isFinite() and fall back to a sane default rather than forwarding NaN.
If accepting user input, validate the raw string with /^\d+$/ before coercing to a number.

Example fix

// before
const memorySizeInMb = Number(process.env.REMOTION_MEMORY);
await renderMediaOnLambda({memorySizeInMb, ...});

// after
const parsed = Number(process.env.REMOTION_MEMORY);
const memorySizeInMb = Number.isFinite(parsed) ? parsed : 2048;
await renderMediaOnLambda({memorySizeInMb, ...});

Defensive patterns

Strategy: type-guard

Validate before calling

const safeMemory = (v: unknown): number => {
  const n = typeof v === 'string' ? Number(v) : v;
  return typeof n === 'number' && !Number.isNaN(n) && Number.isFinite(n) ? n : 2048;
};
await renderMediaOnLambda({memorySizeInMb: safeMemory(raw), ...});

Type guard

const isMemorySize = (v: unknown): v is number =>
  typeof v === 'number' && !Number.isNaN(v) && Number.isFinite(v) && v >= 512 && v <= 10240 && v % 1 === 0;

Prevention

Always coerce and validate memorySizeInMb at the config boundary, not at the Lambda call site.
Default to DEFAULT_MEMORY_SIZE (2048) when input is missing or non-numeric.
Add a unit test that feeds NaN / undefined / Infinity to your config loader and asserts a sane default.

When it happens

Trigger: Calling renderMediaOnLambda() / deploySite() / simulatePermissions() with memorySizeInMb set to the result of a failed Number parse (Number(undefined) === NaN), parseFloat on a non-numeric string, or an arithmetic expression that yields NaN (e.g. 0/0).

Common situations: Reading memorySizeInMb from an environment variable or JSON config without coercion, e.g. Number(process.env.REMOTION_MEMORY) where the env var is unset; computing memory from a formula whose divisor is zero; a CLI flag that parses to undefined then gets Number()-ed.

Related errors

AI-assisted analysis of remotion-dev/remotion@78fe4bb3fd (2026-08-12). Data as JSON: /api/errors/d1f068cb5b414dcd. Report an issue: GitHub.