sveltejs/kit · error · Error

Cannot use `split: true` alongside `edge: true`

Error message

Cannot use `split: true` alongside `edge: true`

What it means

adapter-netlify's split option generates one serverless function per route, while edge functions use a single edge deployment; the two strategies are mutually exclusive. The adapter throws this at adapt() time when both edge and split resolve to true.

Source

Thrown at packages/adapter-netlify/index.js:98

			builder.log.minor(`Publishing to "${publish}"`);

			builder.log.minor('Copying assets...');
			const publish_dir = `${publish}${builder.config.paths.base}`;
			builder.writeClient(publish_dir);
			builder.writePrerendered(publish_dir);

			// Copy user's custom _headers file if it exists
			if (existsSync('_headers')) {
				builder.copy('_headers', join(publish, '_headers'));
			}

			builder.log.minor('Writing Netlify config...');
			write_frameworks_config({ builder });

			if (edge) {
				if (split) {
					throw new Error('Cannot use `split: true` alongside `edge: true`');
				}

				await generate_edge_functions({ builder });
			} else {
				generate_serverless_functions({ builder, split, publish });
			}
		},

		supports: {
			read: () => true,
			instrumentation: () => true
		}
	};
}

/**
 * @param { object } params
 * @param {import('@sveltejs/kit').Builder} params.builder

View on GitHub (pinned to 03f1687fe6)

Solutions

1. Remove `split: true` from the adapter options if you want edge functions
2. Set edge: false (and unset any NETLIFY_EDGE env var) if you want split serverless functions
3. Pick one strategy: split only applies to serverless function generation

Example fix

// before
adapter({ split: true, edge: true })
// after
adapter({ split: false, edge: true })

const { split = false, edge = false } = adapterOptions;
if (split && edge) throw new Error('split and edge are mutually exclusive');

try {
  await vite.build();
} catch (e) {
  if (e.message.includes('split: true` alongside `edge')) {
    console.error('Disable either split or edge in adapter-netlify options');
  }
  throw e;
}

When it happens

Trigger: Configuring adapter-netlify with both `split: true` and `edge: true` (explicitly in svelte.config.js, or edge enabled via the NETLIFY_EDGE env var while split is true in the config).

Common situations: Enabling edge functions by setting an environment variable while forgetting split: true left over from an earlier config; merging team config changes that each set one flag.

Related errors

• The _headers file should be placed in the project root rathe
• The _redirects file should be placed in the project root rat
• Failed to parse netlify.toml: ${err.message}
• The publish directory cannot be set to the site root. Please
• The _headers file should be placed in the project root rathe

AI-assisted analysis of sveltejs/kit@03f1687fe6 (2026-09-02). Data as JSON: /api/errors/76df442d12f61b43. Report an issue: GitHub.