Head to head
Stop guessing which one. Put them side by side.
Up to 4 tools, same rows for each: what it is, what it really costs, the trap, and how to wire it up. The URL carries your picks — send it to anyone.
BraintrustVercel AI SDKAnthropic API / Claude Platform
Quick read
- Free with no card: Vercel AI SDK.
| Field | Braintrustbraintrust.dev | Vercel AI SDKai-sdk.dev | Anthropic API / Claude Platformplatform.claude.com |
|---|---|---|---|
| What it is | An eval-first evaluation platform: datasets, scoring functions, experiment comparison, a prompt playground and production logging in one place. It aims to answer 'did this prompt change make things better or worse' with numbers, rather than only showing traces. | A TypeScript toolkit that gives every model provider one interface — generateText, streamText, structured object generation, tool calling — plus React, Svelte and Vue hooks for streaming UI. It supports 100+ models across 20+ providers; a Python version is in beta. | Anthropic's first-party API for the Claude models, plus the Agent SDK, tool use, MCP connectors, files and batch endpoints. This is a model provider, not a gateway — you get the models Anthropic trains and nothing else, with prompt caching and batch as the main cost levers. |
| Category | Model APIs, routers & observability | Model APIs, routers & observability | Model APIs, routers & observability |
| Cost tier | mixed | free | paid |
| Pricing | Starter free ($10/mo model credits, 1GB data, 10k scores, 14-day retention), Pro $249/mo ($249 credits, 5GB, 50k scores), Enterprise custom. Overage $3-4/GB and $1.50-$2.50 per 1k scores. | Free and open source. No cost beyond the model provider you call; Vercel AI Gateway usage is billed separately if you opt into it. | Per token. Opus 5 $5/$25 per M in/out; Sonnet 5 $2/$10; Haiku 4.5 $1/$5; Fable 5 and Mythos 5 $10/$50. Batch API 50% off; cache reads 0.1x input. |
| Why builders pick it | Turns prompt tweaking from vibes into a regression suite — pin a dataset, run the eval, see which model or prompt scores higher before you ship. Included model credits mean the graders themselves are covered. | Swapping providers is a one-line change, and streaming chat UI that would take a day of SSE plumbing takes about ten lines. It is the default choice for anything Next.js shaped. | Best-in-class coding and agentic tool use, and the only place to get Claude with full feature support. Prompt caching at 0.1x read cost makes long system prompts and big codebase context genuinely affordable. |
| Watch out for | Billing on processed data volume and score counts punishes verbose traces — logging whole documents in every span pushes you past 1GB fast. Free retention is only 14 days. | Major versions have shipped breaking API changes, so older tutorials and AI-generated snippets often will not compile — check which version an example targets before copying it. | Output tokens cost 5x input, and extended thinking bills as output — a reasoning-heavy agent loop can 10x your bill versus the naive estimate. Tier-based rate limits throttle new accounts hard. |
| How to wire it up | npm i braintrust (or pip install braintrust) | npm i ai | npm i @anthropic-ai/sdk (or pip install anthropic) |
| Editor's pick | No | No | No |
Which one did you ship?
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# Tool comparison — Braintrust vs Vercel AI SDK vs Anthropic API / Claude Platform Source: Kbaise, a directory of tools that work with Lovable projects. Pick one and tell me why before writing any integration code. ## Braintrust (braintrust) - URL: https://www.braintrust.dev - Category: Model APIs, routers & observability - Cost: mixed — Starter free ($10/mo model credits, 1GB data, 10k scores, 14-day retention), Pro $249/mo ($249 credits, 5GB, 50k scores), Enterprise custom. Overage $3-4/GB and $1.50-$2.50 per 1k scores. - What it is: An eval-first evaluation platform: datasets, scoring functions, experiment comparison, a prompt playground and production logging in one place. It aims to answer 'did this prompt change make things better or worse' with numbers, rather than only showing traces. - Why builders pick it: Turns prompt tweaking from vibes into a regression suite — pin a dataset, run the eval, see which model or prompt scores higher before you ship. Included model credits mean the graders themselves are covered. - Trap: Billing on processed data volume and score counts punishes verbose traces — logging whole documents in every span pushes you past 1GB fast. Free retention is only 14 days. - Wiring: npm i braintrust (or pip install braintrust) - Full dossier: /api/public/tools/braintrust ## Vercel AI SDK (vercel-ai-sdk) - URL: https://ai-sdk.dev - Category: Model APIs, routers & observability - Cost: free — Free and open source. No cost beyond the model provider you call; Vercel AI Gateway usage is billed separately if you opt into it. - What it is: A TypeScript toolkit that gives every model provider one interface — generateText, streamText, structured object generation, tool calling — plus React, Svelte and Vue hooks for streaming UI. It supports 100+ models across 20+ providers; a Python version is in beta. - Why builders pick it: Swapping providers is a one-line change, and streaming chat UI that would take a day of SSE plumbing takes about ten lines. It is the default choice for anything Next.js shaped. - Trap: Major versions have shipped breaking API changes, so older tutorials and AI-generated snippets often will not compile — check which version an example targets before copying it. - Wiring: npm i ai - Full dossier: /api/public/tools/vercel-ai-sdk ## Anthropic API / Claude Platform (anthropic-api-claude-platform) - URL: https://platform.claude.com - Category: Model APIs, routers & observability - Cost: paid — Per token. Opus 5 $5/$25 per M in/out; Sonnet 5 $2/$10; Haiku 4.5 $1/$5; Fable 5 and Mythos 5 $10/$50. Batch API 50% off; cache reads 0.1x input. - What it is: Anthropic's first-party API for the Claude models, plus the Agent SDK, tool use, MCP connectors, files and batch endpoints. This is a model provider, not a gateway — you get the models Anthropic trains and nothing else, with prompt caching and batch as the main cost levers. - Why builders pick it: Best-in-class coding and agentic tool use, and the only place to get Claude with full feature support. Prompt caching at 0.1x read cost makes long system prompts and big codebase context genuinely affordable. - Trap: Output tokens cost 5x input, and extended thinking bills as output — a reasoning-heavy agent loop can 10x your bill versus the naive estimate. Tier-based rate limits throttle new accounts hard. - Wiring: npm i @anthropic-ai/sdk (or pip install anthropic) - Full dossier: /api/public/tools/anthropic-api-claude-platform ## Quick read - Free with no card: Vercel AI SDK. ## Rules 1. Prefer the free tier when no budget was stated, and say what the ceiling is. 2. Read the full dossier before integrating. 3. Fetch /api/public/models before writing any AI model ID.
Agents can fetch the same thing: GET /api/public/compare?slugs=braintrust,vercel-ai-sdk,anthropic-api-claude-platform