Morph V3 Fast
Morph V3 Fast applies code edit suggestions from frontier models to your source files at high throughput. It supports 81.9K tokens input and 16.4K tokens output. On AI Gateway, pay $0.8 per million input tokens and $1.2 per million output tokens.
import { streamText } from 'ai'
const result = streamText({ model: 'morph/morph-v3-fast', prompt: 'Why is the sky blue?'})Playground
Try out Morph V3 Fast by Morph. Usage is billed to your team at API rates. Free users (those who haven't made a payment) get $5 of credits every 30 days.
Providers
Route requests across multiple providers. Copy a provider slug to set your preference. Visit the docs for more info. Using a provider means you agree to their terms, listed under Legal.
P50 throughput on live AI Gateway traffic, in tokens per second (TPS). Visit the docs for more info.
P50 time to first token (TTFT) on live AI Gateway traffic, in milliseconds. View the docs for more info.
Direct request success rate on AI Gateway and per-provider. Visit the docs for more info.
About Morph V3 Fast
You send the original file, an edit snippet with // ... existing code ... markers, and an optional instruction. You get back the merged file.
Live throughput metrics appear on this page. Each edit uses on the order of 700 to 1,400 tokens, compared to 3,500 to 4,500 for a frontier model rewriting the whole file. The context window is 81.9K tokens; max output is 16.4K tokens.
Routine edits merge reliably: parameter additions, function body swaps, line insertions, and deletions. Harder cases, like logic redistribution across scopes or edits buried in duplicated structures, belong to the heavier variant or Morph's auto router.
``
Planning model --> edit snippet --> v3 Fast --> merged file --> disk
``
Any planning model that outputs lazy edit snippets works. Many tools use the same // ... existing code ... pattern. Drop v3 Fast into the file-write step. Your planning model stays the bottleneck, not the merge. Product details and benchmarks appear on https://morphllm.com/.
What To Consider When Choosing a Provider
- Configuration: This is a merge tool, not an assistant. Place it between your planning model and the filesystem.
- Zero Data Retention: AI Gateway does not currently support Zero Data Retention for this model. See the documentation for models that support ZDR.
- Authentication: AI Gateway authenticates requests using an API key or OIDC token. You do not need to manage provider credentials directly.
When to Use Morph V3 Fast
Best For
- Routine edit merges: Single-function changes, parameter additions, body replacements, and line-level insertions or deletions
- Streaming coding UIs: Users watch edits land and expect fast visual feedback
- High-volume batch runs: Per-edit cost and duration directly affect margin
Consider Alternatives When
- Repeated merge failures: Route problematic edit patterns to the heavier variant
- Automatic routing preference: Morph's
automode handles complexity-based triage - General-purpose coding needs: You need a full coding model, not a merge primitive
Conclusion
Default to v3 Fast and escalate the rare failures. The merge step rarely sits on the critical path.
Frequently Asked Questions
What goes in, what comes out?
You get the merged source file. Send the original file in
<code>tags, an edit snippet in<update>tags with// ... existing code ...markers, and an optional<instruction>. The API follows the OpenAI Chat Completions format.How does deletion work?
v3 Fast treats omitted sections as removal. Leave a section out of the edit snippet and don't add a
// ... existing code ...marker there.What planning models pair well?
Any model that emits lazy edit snippets. The marker pattern isn't proprietary, and mainstream code-generation models already produce it.
Will I hit the context limit?
Unlikely for typical files. The window is 81.9K tokens, so even large single files rarely approach it.
How do I know an edit needs the heavier variant?
Route when merges are wrong. Typical triggers include multi-scope refactors, edits inside heavily repeated patterns, and logic redistribution across functions. Keep v3 Fast as the default otherwise.
Where does the merge sit in the coding-agent pipeline?
The merge step usually finishes before your planning model returns its next chunk. The bottleneck stays upstream, not in the merge.
Where are list prices for this model?
Current rates appear on this page. AI Gateway tracks live pricing across each provider that serves the model.