Bolt.new (StackBlitz) — harness alternatives

Cross-listing of Bolt.new at the harness layer. StackBlitz's WebContainer technology runs full Node.js in-browser; Bolt prompts the user for an app spec, then writes/edits/runs/deploys it entirely in-browser. Full Bolt.new (StackBlitz) — harness record →

  1. 1 Cognition Devin v2 / Spec Mode Agent IDEs & coding harnesses

    also in Agent IDEs & coding harnesses · same storage (kv, file) · same retrieval (injection) · same conflict handling (llm-arbitrate) · same memory unit (document) · also offered managed · also has MCP

    OSS ? Self-host — Managed ✓ MCP ✓ released 2026-10-26 Compare with Bolt.new (StackBlitz) — harness →

  2. 2 Lovable.dev — harness Agent IDEs & coding harnesses

    also in Agent IDEs & coding harnesses · same storage (file) · same retrieval (injection) · same conflict handling (llm-arbitrate) · same memory unit (document) · also offered managed · also has MCP

    OSS ? Self-host — Managed ✓ MCP ✓ Compare with Bolt.new (StackBlitz) — harness →

  3. 3 Replit Agent v3 Agent IDEs & coding harnesses

    also in Agent IDEs & coding harnesses · same storage (file) · same retrieval (injection) · same conflict handling (llm-arbitrate) · same memory unit (document) · also offered managed · also has MCP

    OSS ? Self-host ✓ Managed ✓ MCP ✓ released 2026-03-13 Compare with Bolt.new (StackBlitz) — harness →

  4. 4 MetaGPT Agent IDEs & coding harnesses

    also in Agent IDEs & coding harnesses · same storage (file) · same retrieval (injection) · same conflict handling (llm-arbitrate) · same memory unit (document) · also offered managed

    OSS ✓ Self-host ✓ Managed ✓ MCP ? ★ 71k released 2024-04-22 MIT Compare with Bolt.new (StackBlitz) — harness →

  5. 5 v0 (Vercel) Agent IDEs & coding harnesses

    also in Agent IDEs & coding harnesses · same storage (file) · same retrieval (injection) · same conflict handling (llm-arbitrate) · same memory unit (document) · also offered managed

    OSS ? Self-host — Managed ✓ MCP ? ★ 510 Compare with Bolt.new (StackBlitz) — harness →

  6. 6 Windsurf (now Devin Desktop) Agent IDEs & coding harnesses ⚠ acquired — acquired by OpenAI; now Devin Desktop

    also in Agent IDEs & coding harnesses · same storage (file) · same retrieval (injection) · same conflict handling (llm-arbitrate) · same memory unit (document) · also offered managed · also has MCP

    OSS ? Self-host ✓ Managed ✓ MCP ✓ Compare with Bolt.new (StackBlitz) — harness →

  7. 7 Claude Code (Anthropic) Agent IDEs & coding harnesses

    also in Agent IDEs & coding harnesses · same storage (file) · same retrieval (injection) · same memory unit (document) · also offered managed · also has MCP

    OSS — Self-host ✓ Managed ✓ MCP ✓ ★ 153k released 2026-10-23 proprietary — © Anthropic PBC, use subject to… Compare with Bolt.new (StackBlitz) — harness →

  8. 8 OpenHands Agent IDEs & coding harnesses

    also in Agent IDEs & coding harnesses · same storage (kv, file) · same retrieval (injection) · same conflict handling (llm-arbitrate) · also offered managed · also has MCP

    OSS ✓ Self-host ✓ Managed ✓ MCP ✓ ★ 92k released 2026-09-25 MIT Compare with Bolt.new (StackBlitz) — harness →

Ranked by shared memory design (storage, retrieval, conflict handling, memory unit), same section and shared must-haves (open source, self-hosting, MCP), with adoption as a tie-breaker. ✓ confirmed · — no · ? not in the catalog yet. Want picks for your own requirements? Use the chooser. Checking a whole project? Check your stack.